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+<!DOCTYPE html>
+
+<html><head>
+ <title>PROV-DM Part II: Constraints of the PROV Data Model</title>
+ <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
+ <!--
+ === NOTA BENE ===
+ For the three scripts below, if your spec resides on dev.w3 you can check them
+ out in the same tree and use relative links so that they'll work offline,
+ -->
+<!-- PM -->
+ <style type="text/css">
+ .note { font-size:small; margin-left:50px }
+ </style>
+
+ <script src="http://dev.w3.org/2009/dap/ReSpec.js/js/respec.js" class="remove"></script>
+ <script src="http://www.w3.org/2007/OWL/toggles.js" class="remove"></script>
+
+ <script class="remove">
+ var addExtraReferences = function() {
+ for (var k in extraReferences)
+ berjon.biblio[k] = extraReferences[k];
+ };
+ var extraReferences = {
+ "CLOCK":
+ "Lamport, L. "+
+ "<a href=\"http://research.microsoft.com/users/lamport/pubs/time-clocks.pdf\"><cite>Time, clocks, and the ordering of events in a distributed system</cite></a>."+
+ "Communications of the ACM 21 (7): 558–565. 1978. "+
+ "URL: <a href=\"http://research.microsoft.com/users/lamport/pubs/time-clocks.pdf\">http://research.microsoft.com/users/lamport/pubs/time-clocks.pdf</a> " +
+ "DOI: doi:10.1145/359545.359563.",
+ "CSP":
+ "Hoare, C. A. R. "+
+ "<a href=\"http://www.usingcsp.com/cspbook.pdf\"><cite>Communicating Sequential Processes</cite></a>."+
+ "Prentice-Hall. 1985"+
+ "URL: <a href=\"http://www.usingcsp.com/cspbook.pdf\">http://www.usingcsp.com/cspbook.pdf</a>",
+ "Logic":
+ "W. E. Johnson"+
+ "<a href=\"http://www.ditext.com/johnson/intro-3.html\"><cite>Logic: Part III</cite></a>."+
+ "1924. "+
+ "URL: <a href=\"http://www.ditext.com/johnson/intro-3.html\">http://www.ditext.com/johnson/intro-3.html</a>",
+ "PROV-SEM":
+ "James Cheney "+
+ "<a href=\"http://www.w3.org/2011/prov/wiki/FormalSemanticsStrawman\"><cite>Formal Semantics Strawman</cite></a>. "+
+ "2011, Work in progress. "+
+ "URL: <a href=\"http://www.w3.org/2011/prov/wiki/FormalSemanticsStrawman\">http://www.w3.org/2011/prov/wiki/FormalSemanticsStrawman</a>",
+
+ "PROV-PRIMER":
+ "Yolanda Gil and Simon Miles (eds.) Khalid Belhajjame, Helena Deus, Daniel Garijo, Graham Klyne, Paolo Missier, Stian Soiland-Reyes, and Stephan Zednik "+
+ "<a href=\"http://www.w3.org/TR/prov-primer/\"><cite>Prov Model Primer</cite></a>. "+
+ "2011, Working Draft. "+
+ "URL: <a href=\"http://www.w3.org/TR/prov-primer/\">http://www.w3.org/TR/prov-primer/</a>",
+
+ "PROV-O":
+ "Satya Sahoo and Deborah McGuinness (eds.) Khalid Belhajjame, James Cheney, Daniel Garijo, Timothy Lebo, Stian Soiland-Reyes, and Stephan Zednik "+
+ "<a href=\"http://www.w3.org/TR/prov-o/\"><cite>Provenance Formal Model</cite></a>. "+
+ "2011, Working Draft. "+
+ "URL: <a href=\"http://www.w3.org/TR/prov-o/\">http://www.w3.org/TR/prov-o/</a>",
+
+ "PROV-AQ":
+ "Graham Klyne and Paul Groth (eds.) Luc Moreau, Olaf Hartig, Yogesh Simmhan, James Meyers, Timothy Lebo, Khalid Belhajjame, and Simon Miles "+
+ "<a href=\"http://www.w3.org/TR/prov-aq/\"><cite>Provenance Access and Query</cite></a>. "+
+ "2011, Working Draft. "+
+ "URL: <a href=\"http://www.w3.org/TR/prov-aq/\">http://www.w3.org/TR/prov-aq/</a>",
+ };
+ var respecConfig = {
+ // specification status (e.g. WD, LCWD, NOTE, etc.). If in doubt use ED.
+ specStatus: "ED",
+
+ // the specification's short name, as in http://www.w3.org/TR/short-name/
+ shortName: "prov-dm-constraints",
+
+ // if your specification has a subtitle that goes below the main
+ // formal title, define it here
+ //subtitle : "Initial draft (WD4) for internal discussion",
+
+ // if you wish the publication date to be other than today, set this
+ //publishDate: "2012-02-01",
+
+ // if the specification's copyright date is a range of years, specify
+ // the start date here:
+ copyrightStart: "2011",
+
+ // if there is a previously published draft, uncomment this and set its YYYY-MM-DD date
+ // and its maturity status
+ previousPublishDate: "2012-02-02",
+ previousMaturity: "WD",
+
+ // if there a publicly available Editor's Draft, this is the link
+ edDraftURI: "http://dvcs.w3.org/hg/prov/raw-file/default/model/working-dir/prov-dm-constraints.html",
+
+ // if this is a LCWD, uncomment and set the end of its review period
+ // lcEnd: "2009-08-05",
+
+ // if you want to have extra CSS, append them to this list
+ // it is recommended that the respec.css stylesheet be kept
+ extraCSS: ["http://dev.w3.org/2009/dap/ReSpec.js/css/respec.css", "./extra.css"],
+
+ // editors, add as many as you like
+ // only "name" is required
+ editors: [
+ { name: "Luc Moreau", url: "http://www.ecs.soton.ac.uk/~lavm/",
+ company: "University of Southampton" },
+ { name: "Paolo Missier", url: "http://www.cs.ncl.ac.uk/people/Paolo.Missier",
+ company: "Newcastle University" },
+ ],
+
+ // authors, add as many as you like.
+ // This is optional, uncomment if you have authors as well as editors.
+ // only "name" is required. Same format as editors.
+
+ //authors: ,
+
+ // name of the WG
+ wg: "Provenance Working Group",
+
+ // URI of the public WG page
+ wgURI: "http://www.w3.org/2011/prov/",
+
+ // name (with the @w3c.org) of the public mailing to which comments are due
+ wgPublicList: "public-prov-wg",
+
+ // URI of the patent status for this WG, for Rec-track documents
+ // !!!! IMPORTANT !!!!
+ // This is important for Rec-track documents, do not copy a patent URI from a random
+ // document unless you know what you're doing. If in doubt ask your friendly neighbourhood
+ // Team Contact.
+ wgPatentURI: "http://www.w3.org/2004/01/pp-impl/46974/status",
+
+ // Add extraReferences to bibliography database
+ preProcess: [addExtraReferences],
+ };
+ </script>
+ </head>
+ <body>
+
+ <section id="abstract">
+<p>
+<b>Editors' working copy can change at any time. </b>
+</p>
+ </section>
+
+<section id="sotd">
+<b>Editors' working copy can change at any time. </b>
+</section>
+
+
+<div class="buttonpanel">
+<form action="#"><p>
+<input id="hide-bnf" onclick="set_display_by_class('div','grammar','none'); set_display_by_id('hide-bnf','none'); set_display_by_id('show-bnf','');" type="button" value="Hide Grammar" />
+<input id="show-bnf" onclick="set_display_by_class('div','grammar',''); set_display_by_id('hide-bnf',''); set_display_by_id('show-bnf','none');" style="display: none" type="button"
+value="Show Grammar" />
+<input id="hide-examples" onclick="set_display_by_class('div','anexample','none'); set_display_by_id('hide-examples','none'); set_display_by_id('show-examples','');" type="button"
+value="Hide Examples" />
+<input id="show-examples" onclick="set_display_by_class('div','anexample',''); set_display_by_id('hide-examples',''); set_display_by_id('show-examples','none');" style="display: none"
+type="button" value="Show Examples" />
+</p>
+</form>
+</div>
+
+
+ <section id="introduction">
+ <h2>Introduction<br>
+</h2>
+
+<p>
+For the purpose of this specification, <dfn>provenance</dfn> is defined as a record that describes the people,
+institutions, entities, and activities, involved in producing,
+influencing, or delivering a piece of data or a thing in the world.
+In particular, the provenance of information is crucial in deciding
+whether information is to be trusted, how it should be integrated with
+other diverse information sources, and how to give credit to its
+originators when reusing it. In an open and inclusive environment
+such as the Web, users find information that is often contradictory or
+questionable: provenance can help those users to make trust judgments.
+</p>
+
+
+<p>
+The idea that a single way of representing and collecting provenance could be adopted internally by all systems does not seem to be realistic today. Instead, a pragmatic approach is to
+consider a core data model for provenance that allows domain and application specific representations of provenance to be translated into such a data model and exchanged between systems.
+Heterogeneous systems can then export their provenance into such a core data model, and applications that need to make sense of provenance in heterogeneous systems can then import it,
+process it, and reason over it.</p>
+
+<p>Thus, the vision is that different provenance-aware systems natively adopt their own model for representing their provenance, but a core provenance data model can be readily adopted as a
+provenance <em>interchange</em> model across such systems.</p>
+
+<p>A set of specifications, referred to as the PROV family of specifications, define the various aspects
+that are necessary to achieve this vision in an inter-operable
+way, the first of which is this document:</p>
+<ul>
+<li>PROV-DM: a data model for provenance, accompanied with a notation to express instances of that data model for human consumption (this document); </li>
+<li>PROV-O: a normative serialization of PROV-DM in RDF [[!PROV-O]], specified by means of a mapping to the OWL2 Web Ontology Language [[!OWL2-SYNTAX]];</li>
+<li>PROV-AQ: the mechanisms for accessing and querying provenance [[!PROV-AQ]];</li>
+<li>PROV-PRIMER: a primer for the PROV approach [[!PROV-PRIMER]];</li>
+<li>PROV-SEM: semantics of the PROV-DM data model [[PROV-SEM]];</li>
+</ul>
+
+
+<p>
+The PROV-DM data model for provenance consists of a set of core
+concepts, and a few common relations, based on these core concepts. PROV-DM is a domain-agnotisc model, but with clear extensibility points allowing further domain-specific and
+application-specific extensions to be defined.</p>
+
+<p>This specification also introduces
+PROV-ASN, an abstract syntax that is primarily aimed at human consumption. PROV-ASN allows
+serializations of PROV-DM instances to be written in a technology independent manner,
+it facilitates its mapping to concrete syntax, and it is used as the basis for a
+formal semantics. This specification uses instances of provenance written in PROV-ASN
+to illustrate the data model.
+</p>
+
+ <section id="structure-of-this-document">
+<h3>Structure of this Document</h3>
+
+<p>In <a href="#preliminaries">section 2</a>, a set of preliminaries are introduced, including concepts that underpin PROV-DM and motivations for the PROV-ASN notation.</p>
+
+<p><a href="#prov-dm-overview">Section 3</a> provides an overview of PROV-DM listing its core types and their relations.</p>
+
+<p>In <a href="#prov-dm-example">section 4</a>, PROV-DM is
+applied to a short scenario, encoded in PROV-ASN, and illustrated
+graphically.</p>
+
+<p><a href="#data-model-concepts">Section 5</a> provides the normative definition of PROV-DM and the notation PROV-ASN.</p>
+
+<p><a href="#common-relations">Section 6</a> introduces further relations offered by PROV-DM, including relations for data collections and domain-independent common relations.</p>
+
+<p><a href="#interpretation">Section 7</a> provides an interpretation of PROV-DM in terms of ordering constraints between events, and also presents a set of structural constraints to be
+satisfied by PROV-DM.</p>
+
+<p><a href="#extensibility-section">Section 8</a> summarizes PROV-DM extensibility points.</p>
+
+<p><a href="#resource-section">Section 9</a> discusses how PROV-DM can be applied to the notion of resource.</p>
+
+
+ </section>
+
+<section id="prov-dm-namespace">
+ <h3>PROV-DM Namespace</h3>
+
+
+<p>The PROV-DM namespace is <span class="name">http://www.w3.org/ns/prov-dm/</span> (TBC).</p>
+
+<p> All the elements, relations, reserved names and attributes introduced in this specification belong to the PROV-DM namespace.</p>
+
+<div class="issue">
+There is a desire to use a single namespace that all specifications of the PROV family can share to refer to common provenance terms. This is <a href="http://www.w3.org/2011/prov/track/issues/224">ISSUE-224</a>.
+</div>
+
+</section>
+
+
+ <section id="conventions">
+<h3>Conventions</h3>
+
+
+
+<p>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
+ NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and
+ "OPTIONAL" in this document are to be interpreted as described in
+ [[!RFC2119]].</p>
+ </section>
+
+</section>
+
+
+<section id='preliminaries'>
+<h2>Preliminaries</h2>
+
+ <section id='conceptualization'>
+<h3>A Conceptualization of the World</h3>
+
+
+
+ <section id='section-entity-activity-agent'>
+<h4>Entity, Activity, Agent</h4>
+
+
+
+
+<p>This specification is based on a conceptualization of the world
+that is described in this section. In the world (whether real or not),
+there are things, which can be physical, digital, conceptual, or
+otherwise, and activities involving things. </p>
+
+<p>When we talk about things in the world in natural language and even when we assign identifiers, we are often imprecise in ways that make it difficult to clearly and unambiguously report
+provenance: a resource with a URL may be understood as referring to a report available at that URL, the version of the report available there today, the report independent of where it is
+hosted over time, etc.</p>
+
+<p>Hence, to accommodate different perspectives on things and their situation in the world as perceived by us, we introduce the idea of a characterized thing, which refers to a thing and its
+situation in the world, as characterized by someone. We then define an <dfn id="concept-entity">entity</dfn> as an identifiable characterized thing. An entity <em>fixes some aspects</em> of
+a thing and its situation in the world, so that it becomes possible to express its provenance, and what causes these specific aspects to be as such. An alternative entity may fix other
+aspects, and its provenance may be different.</p>
+
+<div class="anexample" id="a-report-example">
+Different users may take different perspectives on a resource with
+a URL. These perspectives in this conceptualization of the world are
+referred to as entities. Three such entities may be
+expressed:
+<ul>
+<li>a report available at a URL: fixes the nature of the thing, i.e. a document, and its location; </li>
+<li>the version of the report available there today: fixes its version number, contents, and its date;</li>
+<li>the report independent of where it is hosted and of its content over time: fixes the nature of the thing as a conceptual artifact.</li></ul>
+The provenance of these three entities may differ, and may be along the following lines:
+<ul>
+<li>the provenance of a report available at a URL may include: the act of publishing it and making it available at a given location, possibly under some license and access control;</li>
+<li>the provenance of the version of the report available there today may include: the authorship of the specific content, and reference to imported content;</li>
+<li>the provenance of the report independent of where it is hosted over time may include: the motivation for writing the report, the overall methodology for producing it, and the broad team
+involved in it.</li>
+</ul>
+</div>
+
+<p>We do not assume that any characterization is more important than any other, and in fact, it is possible to describe the processing that occurred for the report to be commissioned, for
+individual versions to be created, for those versions to be published at the given URL, etc., each via a different entity that characterizes the report appropriately.</p>
+
+<p>In the world, <dfn id="concept-activity">activities</dfn> involve
+entities in multiple ways: consuming them, processing them,
+transforming them, modifying them, changing them, relocating
+them, using them, generating them, being associated with them,
+etc.</p>
+
+
+<p>An <dfn id="concept-agent">agent</dfn> is a type of entity that takes an active role in an activity such that it can be assigned some degree of responsibility for the activity taking
+place.
+This definition intentionally stays away from using concepts such as enabling, causing, initiating, affecting, etc, because any entities also enable, cause, initiate, and affect in some way
+the activities. So the notion of having some degree of responsibility is really what makes an agent. </p>
+
+<p> Even software agents can be assigned some responsibility for the effects they have in the world, so for example if one is using a Text Editor and one's laptop crashes, then one would say
+that the Text Editor was responsible for crashing the laptop. If one invokes a service to buy a book, that service can be considered responsible for drawing funds from one's bank to make
+the purchase (the company that runs the service and the web site would also be responsible, but the point here is that we assign some measure of responsibility to software as well). So when
+someone models software as an agent for an activity in our model, they mean the agent has some responsibility for that activity.
+</p>
+
+<p>PROV-DM considers agents as a type of entity so that the model can be
+ used to represent the provenance of the agents themselves. For
+ example, a grammarchecker software may be an agent of a document
+ preparation activity, but itself can have a provenance record that
+ states who its vendor is.</p>
+
+
+<p> In this specification, the qualifier 'identifiable' is implicit whenever a reference is made to an activity, agent, or an entity.</p>
+
+</section>
+
+
+ <section id='section-time-event'>
+<h4>Time and Event</h4>
+
+<p>Time is critical in the context of provenance, since it can help corroborate provenance claims. For instance, if an entity is claimed to be obtained by transforming another, then the
+latter must have existed before the former. If it is not the case, then there is something wrong with such a provenance claim. </p>
+
+<p> Although time is critical, we should also recognize that provenance can be used in many different contexts: in a single system, across the Web, or in spatial data management, to name a
+few. Hence, it is a design objective of PROV-DM to minimize the assumptions about time, so that PROV-DM can be used in varied contexts. </p>
+
+
+<p>Furthermore, consider two activities that started at the same time
+instant. Just by referring to that instant, we cannot distinguish
+which activity start we refer to. This is particularly relevant if we
+try to explain that the start of these activities had different
+reasons. We need to be able to refer to the start of an activity as a
+first class concept, so that we can talk about it and about its
+relation with respect to other similar starts. </p>
+
+
+<p>Hence, in our conceptualization of the world, an <em>instantaneous event</em>, or <dfn id="dfn-event">event</dfn> for short, happens in the world and marks a change in the world, in its
+activities and in its entities.
+The term "event" is commonly used in process algebra with a similar meaning. For instance, in CSP [[CSP]], events represent communications or interactions; they are assumed to be atomic and
+instantaneous.</p>
+
+
+
+
+<section id="types-of-events">
+<h4>Types of Events</h4>
+
+<p>Four kinds of <a title="event">instantaneous events</a> underpin the PROV-DM data model. The <strong>activity start</strong> and <strong>activity end</strong> events demarcate the
+beginning and the end of activities, respectively. The <strong>entity generation</strong> and <strong>entity usage</strong> events demarcate the characterization interval for entities. More
+specifically:
+
+</p>
+
+<p>An <dfn id="dfn-generation-event">entity generation event</dfn> is the <a title="event">instantaneous event</a> that marks the final instant of an entity's creation timespan, after which
+it becomes available for use.</p>
+
+<p>An <dfn id="dfn-usage-event">entity usage event</dfn> is the <a title="event">instantaneous event</a> that marks the first instant of an entity's consumption timespan by an activity.</p>
+
+<p>An <dfn id="dfn-start-event">activity start event</dfn> is the <a title="event">instantaneous event</a> that marks the instant an activity starts.</p>
+
+<p>An <dfn id="dfn-end-event">activity end event</dfn> is the <a title="event">instantaneous event</a> that marks the instant an activity ends.</p>
+
+</section>
+
+<section id="event-ordering">
+<h4>Event Ordering</h4>
+
+<p>To allow for minimalistic clock assumptions, like Lamport
+[[CLOCK]], PROV-DM relies on a notion of relative ordering of <a title="event">instantaneous events</a>,
+without using physical clocks. This specification assumes that a partial order exists between <a title="event">instantaneous events</a>.
+</p>
+
+
+<p>Specifically, <dfn id="dfn-follows">follows</dfn> is a partial
+order between <a title="event">instantaneous events</a>, indicating that an <a title="event">instantaneous event</a> occurs at the same time as or after another.
+For symmetry, <dfn id="dfn-precedes">precedes</dfn> is defined as
+the inverse of follows. (Hence, these relations are reflexive and transitive.)</p>
+
+
+<p> How such partial order is realized in practice is beyond the scope
+of this specification. This specification only assumes that
+each <a title="event">instantaneous event</a> can be mapped to an instant in some form of
+timeline. The actual mapping is not in scope of this
+specification. Likewise, whether this timeline is formed of a single
+global timeline or whether it consists of multiple Lamport's style
+clocks is also beyond this specification. It is anticipated
+that <a>follows</a> and <a>precedes</a> correspond to some ordering
+over this timeline.
+</p>
+
+
+<p>This specification introduces a set of "temporal interpretation"
+rules allowing the derivation of <a title="event">instantaneous event</a> ordering constraints from
+provenance records. According to such temporal interpretation,
+provenance records MUST satisfy such constraints. We note that the
+actual verification of such ordering constraints is outside the
+scope of this specification. </p>
+
+<p>PROV-DM also allows for time observations to be inserted in specific
+provenance records, for each recognized <a title="event">instantaneous event</a> introduced
+in this specification. The presence of a time observation for a
+given <a title="event">instantaneous event</a> fixes the mapping of this <a title="event">instantaneous event</a> to the
+timeline. It can also help with the verification of associated
+ordering constraints (though, again, this verification is outside the
+scope of this specification).
+</p>
+
+
+
+</section>
+
+<div class='issue'> We need to refine the definition of entity and activity, and all the concepts in general. This is <a href="http://www.w3.org/2011/prov/track/issues/223">ISSUE-223</a>.</div>
+ </section>
+
+ </section>
+
+ <section id="prov-asn-intro">
+<h3>PROV-ASN: The Provenance Abstract Syntax Notation</h3>
+
+<p>This specification defines PROV-DM, a data model for provenance, consisting of records describing how people, entities, and activities, were involved in producing,
+influencing, or delivering a piece of data or a thing in the world.</p>
+
+<p>This specification also relies on a language, PROV-ASN, the Provenance Abstract Syntax Notation, to express
+<em>instances</em> of that data model.
+For each construct of PROV-DM, a corresponding ASN expression is introduced, by way of a production in the ASN grammar. </p>
+
+
+
+
+
+<p>PROV-ASN is an abstract syntax, whose goals are:
+<ul>
+<li>to allow serializations of PROV-DM instances in a technology independent manner, which makes it more readable for human consumption;
+<li>to facilitate the mapping of PROV-DM to concrete syntax;
+<li>to provide the basis for a formal semantics.
+</ul>
+
+<p>This specification provides a grammar for PROV-ASN. Each record of the PROV-DM data model is explained
+in terms of the production of this grammar.</p>
+
+
+
+<p>The formal semantics of PROV-DM is defined at
+[[PROV-SEM]] and its encoding in the OWL2 Web Ontology Language at [[!PROV-O]].
+</p>
+
+
+
+
+
+
+ </section>
+
+ <section id="representation-record-assertion-inference">
+<h3>Representation, Record, Assertion, and Inference</h3>
+
+<p>
+PROV-DM is a provenance data model designed to express <em>representations</em> of the world. Such representations are structured according to a set of <em>records</em>.
+</p>
+
+<div class="anexample">
+A file at some point during its lifecycle, which includes multiple edits by multiple people, can be represented by its location in the file system, a creator, and content.
+</div>
+
+
+<p>
+These records are relative to an asserter, and in that sense constitute assertions stating properties of the world, as represented by an asserter. Different asserters will normally
+contribute different records expressive different representations of the world.
+This specification does not define a notion of consistency between different sets of records (whether by the same asserter or different asserters).
+The data model provides the means to associate attribution to assertions.
+</p>
+
+<div class="anexample">
+An alternative representation of the above file is a set of blocks in a hard disk.
+</div>
+
+
+<p>The data model is designed to capture activities that happened in the past, as opposed to activities
+that may or will happen.
+However, this distinction is not formally enforced.
+Therefore, all PROV-DM records SHOULD be interpreted as a description of what has happened, as opposed to what may or will happen.</p>
+
+
+
+<p>
+This specification does not prescribe the means by which an asserter arrives at records; for example, records can be composed on the basis of observations, reasoning, or any other means.
+</p>
+
+
+<p>
+Sometimes, inferences about the world can be made from records
+conformant to the PROV-DM data model. When this is the case, this
+specification defines such inferences, allowing new provenance records
+to be inferred from existing ones. Hence, representations of the world
+can result either from direct assertions of records by asserters or from inference of new records
+by application of inference rules defined by this specification.
+</p>
+
+
+
+</section>
+ <section id="grammar-notation">
+<h3>Grammar Notation</h3>
+
+<p>This specification includes a grammar for PROV-ASN expressed using the Extended Backus-Naur Form (EBNF) notation.</p>
+
+<div class="grammar">
+<p> Each production rule (or <dfn>production</dfn>, for short) in the grammar defines one non-terminal symbol, in the form:</p>
+<p>
+<span class="nonterminal">E</span> ::= <em>expression</em>
+</p>
+
+
+Within the expression on the right-hand side of a rule, the following expressions are used to match strings of one or more characters:
+<ul>
+<li>
+<span class="nonterminal">E</span>: matches term satisfying rule for symbol E.
+</li>
+
+<li>
+<span class="name">abc</span>: matches the literal string inside the single quotes.
+</li>
+
+
+<li>
+<span class="optional"><em>expression</em></span>: matches <em>expression</em> or nothing; optional <em>expression</em>.
+</li>
+
+<li>
+<span class="plus"><em>expression</em></span>: matches one or more occurrences of <em>expression</em>.
+</li>
+
+<li>
+<span class="star"><em>expression</em></span>: matches zero or more occurrences of <em>expression</em>.
+</li>
+
+</ul>
+</div>
+
+</section>
+</section>
+
+
+
+
+<section id="data-model-concepts">
+
+<h2>PROV-DM Core</h2>
+
+<p>This section contains the normative specification of PROV-DM core, the core of the PROV data model.</p>
+
+ <section id="PROV-DM-record">
+
+<h3>Record</h3>
+
+<p>This specification introduced <a>provenance</a> as a set of records
+describing the people, institutions, entities, and activities,
+involved in producing, influencing, or delivering a piece of data or a
+thing in the world. PROV-DM is a data model defining the structure and
+meaning of such records.</p>
+
+
+<p>Concretely, PROV-DM consists of a set of constructs to formulate representations of the world and constraints that must be satisfied by them.
+A PROV-DN <dfn id="dfn-Record">record</dfn> is a body of information about something which is of interest from a provenance viewpoint. PROV-DM records may be asserted directly or may be
+inferred from others.
+</p>
+
+<p>
+PROV-DM records are typed and can be among the following types, introduced one by one in this section:
+<a>entity record</a>,
+<a>activity record</a>,
+<a>agent record</a>,
+<a>note record</a>,
+<a>generation record</a>,
+<a>usage record</a>,
+<a>derivation record</a>,
+<a>activity association record</a>,
+<a>responsibility record</a>,
+<a>start record</a>,
+<a>end record</a>,
+<a>alternate record</a>,
+<a>specialization record</a>,
+<a>annotation record</a>, and
+<a>account record</a>.
+</p>
+
+
+<p>
+Furthermore, PROV-DM includes a "house-keeping construct", a record container,
+ used to wrap PROV-DM records and facilitate their interchange.
+Hence, by creating a set of PROV-DM records and packaging them into a record container,
+one forms a provenance record. </p>
+
+<p>In PROV-ASN, such representations of the world MUST be conformant with the toplevel <a>production</a> <span class="nonterminal">record</span> of the grammar. These <span
+class="nonterminal">record</span>s are grouped in three categories:
+<span class="nonterminal">elementRecord</span> (see section <a href="#record-element">Element</a>),
+<span class="nonterminal">relationRecord</span> (see section <a href="#record-relation">Relation</a>), and
+<span class="nonterminal">accountRecord</span> (see section <a href="#record-Account">Account</a>).</p>
+
+
+<div class='grammar'>
+<span class="nonterminal">record</span> ::=
+<span class="nonterminal">elementRecord</span>
+| <span class="nonterminal">relationRecord</span>
+| <span class="nonterminal">accountRecord</span>
+<br/>
+<!-- -->
+<br/>
+<span class="nonterminal">elementRecord</span> ::=
+<span class="nonterminal">entityRecord</span>
+| <span class="nonterminal">activityRecord</span>
+| <span class="nonterminal">agentRecord</span>
+| <span class="nonterminal">noteRecord</span> <br/>
+<!-- -->
+<br/>
+<span class="nonterminal">relationRecord</span> ::=
+<span class="nonterminal">generationRecord</span>
+| <span class="nonterminal">usageRecord</span>
+| <span class="nonterminal">derivationRecord</span>
+| <span class="nonterminal">activityAssociationRecord</span>
+| <span class="nonterminal">responsibilityRecord</span>
+| <span class="nonterminal">startRecord</span>
+| <span class="nonterminal">endRecord</span>
+| <span class="nonterminal">alternateRecord</span>
+| <span class="nonterminal">specializationRecord</span>
+| <span class="nonterminal">annotationRecord</span>
+</div>
+
+
+<p>In PROV-ASN, a record container is compliant with the production <span class="nonterminal">recordContainer</span> (see section <a href="#RecordContainer">Record Container</a>). </p>
+
+</section>
+
+ <section id="record-element">
+<h3>Element</h3>
+
+<p>This section describes all the PROV-DM records referred to as element records. (In PROV-ASN, such records are conformant to the <span class='nonterminal'>elementRecord</span> production
+of the grammar.)</p>
+
+<div class="issue">
+There is still some confusion about what the identifiers really denote. For instance, are they entity identifiers or entity record identifiers. This is <a
+href="http://www.w3.org/2011/prov/track/issues/183">ISSUE-183</a>.
+An example and questions appear in <a href="http://www.w3.org/2011/prov/track/issues/215">ISSUE-215</a>. A related issued is also raised in <a
+href="http://www.w3.org/2011/prov/track/issues/145">ISSUE-145</a>.
+</div>
+
+ <section id="record-Entity">
+
+<h4>Entity Record</h4>
+
+<p>In PROV-DM, an <dfn id="dfn-entity">entity record</dfn> is a representation of an entity.</p>
+
+
+<p>Examples of entities include a car on a road, a linked data set, a sparse-matrix matrix of floating-point numbers, a document in a directory, the same document published on the Web, and
+meta-data embedded in a document.</p>
+
+<p>An entity record, noted <span class="name">entity(id, [ attr1=val1, ...])</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an identifier <span class="name">id</span> identifying an entity; </li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">[ attr1=val1, ...]</span>, representing this entity's situation in the world.</li>
+</ul>
+
+
+<p>
+The assertion of an entity record states, from a given asserter's viewpoint, the existence of an entity, whose situation in the world is represented by the attribute-value pairs, which
+remain unchanged during a characterization interval, i.e. a continuous interval between two <a title="event">instantaneous events</a> in the world.
+</p>
+
+<p>
+In PROV-ASN, an entity record's text matches the <span class="nonterminal">entityRecord</span> production of the grammar defined in this specification document.
+</p>
+
+<div class='grammar'>
+<span class="nonterminal">entityRecord</span> ::=
+<span class="name">entity</span>
+<span class="name">(</span>
+<span class="nonterminal">identifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span><br/><br/>
+<!-- -->
+<span class="nonterminal">optional-attribute-values</span> ::=
+<span class="optional"><span class="name">,</span>
+<span class="name">[</span>
+<span class="nonterminal">attribute-values</span>
+<span class="name">]</span>
+</span><br/>
+<span class="nonterminal">attribute-values</span> ::=
+<span class="nonterminal">attribute-value</span>
+| <span class="nonterminal">attribute-value</span> <span class="name">,</span> <span class="nonterminal">attribute-values</span>
+<br/>
+<span class="nonterminal">attribute-value</span> ::=
+<span class="nonterminal">attribute</span>
+<span class="name">=</span>
+<span class="nonterminal">Literal</span>
+<br/>
+</div>
+
+<div class="anexample">
+<p>
+The following entity record,</p>
+<pre class="codeexample">
+entity(e0, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice" ])
+</pre>
+states the existence of an entity, denoted by identifier <span class="name">e0</span>, with type <span class="name">File</span> and path <span class="name">/shared/crime.txt</span> in the
+file system, and creator alice The attributes <span class="name">path</span> and <span class="name">creator</span> are application specific, whereas the attribute <span
+class="name">type</span> is reserved in the PROV-DM namespace.
+</div>
+
+Further considerations:
+<ul>
+<li>
+The entity identifier <span class="name">id</span> contained in an entity record is expected to be unique among all the identifiers contained in the current account's records.
+This constraint is elaborated upon in <a href="#identifiable-record-in-account">identifiable-record-in-account</a>. It means that the current account does not contain any other record for
+this identifier. Effectively, <span class="name">id</span> acts as a <em>local</em> identifier for this record. In this specification, whenever we write "an entity record identified by ...
+", this identification is to be understood in the context of the account that defines it. </li>
+<li>If an asserter wishes to characterize an entity with the same attribute-value pairs over several intervals, then they are required to create multiple entity records (either by direct
+assertion or by inference), each with its own identifier (so as to allow potential dependencies between the various entity records to be expressed). </li>
+
+<li>There is no assumption that the set of attributes is complete and that the attributes are independent or orthogonal of each other.</li>
+
+<li>A characterization interval may collapse into a single instant.</li>
+
+<li>An entity assertion
+ is about a thing, whose situation in the world may be variant.
+ An entity record is asserted at a particular point and is invariant, in the sense that
+its attributes are given a value as part of that assertion.
+</li>
+
+
+<li id='attribute-occurrence-in-entity-record'>The attributes
+occurring in an entity record MUST be declared in the namespace
+referred to by their prefix according to
+<a href="#record-attribute">Section record-attribute</a>. Furthermore,
+for each attribute, a namespace also declares the number of
+occurrences it may have in a list of attributes. An entity record is
+valid if the number of occurrences of any of its attributes is
+compatible with this attribute's declaration it its namespace. This
+property applies to all types of records, and is referred to
+as <a>attribute occurrence validity</a>.</li>
+
+
+<li>Activities are not represented by entity records, but instead by activity records, as explained below.</li>
+</ul>
+
+<p>Furthermore, section <a href="#record-ActivityAssociation">Activity Association Record</a>, introduces the idea of <em>plans</em> being associated with activities:</p>
+<ul>
+<li><span class="name">Plan</span>: entities of type <a >plan</a> that represent a set of
+actions or steps intended by one or more agents to achieve some goals.</li>
+</ul>
+
+
+
+
+
+<div class='issue'>The characterization interval of an entity record is currently implicit. Making it explicit would allow us to define alternateOf and specializationOf more precisely.
+Beginning and end of characterization interval could be expressed by attributes (similarly to activities).
+How do we define the end of an entity? This is <a href="http://www.w3.org/2011/prov/track/issues/204">ISSUE-204</a>.
+</div>
+
+
+
+
+ </section>
+
+ <section id="record-Activity">
+
+<h3>Activity Record</h3>
+<p>In PROV-DM, an <dfn id="dfn-activity">activity record</dfn> is a representation of an identifiable activity, which performs a piece of work.</p>
+
+
+<p>An activity, represented by an activity record, is delimited by its <a title="activity start event">start</a> and its <a title="activity end event">end</a> events; hence, it occurs over
+an interval delimited by two <a title="event">instantaneous events</a>. However, an activity record need not mention time information, nor duration, because they may not be known.</p>
+
+<p>If start and end times are known, they are expressed as <em>attributes</em> of an activity, where the interpretation of attribute in the context of an activity record is the same as the
+interpretation of attribute for entity record: an activity record's attribute remains constant for the duration of the activity it represents. Further characteristics of the activity in the
+world can be represented by other attribute-value pairs, which MUST also remain unchanged during the activity duration.</p>
+
+<p>
+Examples of activities include driving a car from Boston to Cambridge, assembling a data set based on a set of measurements, performing a statistical analysis over a data set, sorting news
+items according to some criteria, running a sparql query over a triple store, editing a file, and publishing a web page. </p>
+
+<p> An activity record, written <span class="name">activity(id, st, et, [ attr1=val1, ...])</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an identifier <span class="name">id</span> identifying an activity;</li>
+<!--<li><em>recipeLink</em>: an OPTIONAL <a href="#record-RecipeLink">recipe link</a> <span class="name">rl</span>, which consists of a domain specific specification of the activity;</li>-->
+<li><em>startTime</em>: an OPTIONAL time <span class="name">st</span> indicating the start of the activity;</li>
+<li><em>endTime</em>: an OPTIONAL time <span class="name">et</span> indicating the end of the activity;</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">[ attr1=val1, ...]</span>, representing other attributes of this activity that hold for its whole
+duration.</li>
+</ul>
+
+<p>In PROV-ASN, an activity record's text matches the <span class='nonterminal'>activityRecord</span> production of the grammar defined in this specification document.</p>
+
+
+
+<div class='grammar'>
+<span class="nonterminal">activityRecord</span> ::=
+<span class="name">activity</span>
+<span class="name">(</span>
+<span class="nonterminal">identifier</span>
+<span class="name">,</span>
+<span class="optional"><span class="nonterminal">time</span></span>
+<span class="name">,</span>
+<span class="optional"><span class="nonterminal">time</span></span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<div class="anexample">
+<p>
+The following activity record</p>
+<pre class="codeexample">
+activity(a1,2011-11-16T16:05:00,2011-11-16T16:06:00,
+ [ex:host="server.example.org",prov:type="ex:edit" %% xsd:QName])
+</pre>
+<p>states the existence of an activity identified by <span class="name">a1</span>, start time <span class="name">2011-11-16T16:05:00</span>, and end time <span
+class="name">2011-11-16T16:06:00</span>, running on host <span class="name">server.example.org</span>, and of type <span class="name">edit</span> (declared in some namespace with prefix
+<span class="name">ex</span>). The attribute <span class="name">host</span> is application specific, but MUST hold for the duration of activity. The attribute <span
+class="name">type</span> is a reserved attribute of PROV-DM, allowing for subtyping to be expressed.</p>
+</div>
+
+<div class="interpretation-forward">
+For the interpretation of an activity record, see <a href="#start-precedes-end">start-precedes-end</a>.
+</div>
+
+<!--
+<p>The mere existence of an activity assertion entails some <a>event</a> ordering in the world, since an <a>activity start event</a> always <a>precedes</a> the corresponding <a>activity end
+event</a>. This is expressed by constraint <a href="#start-precedes-end">start-precedes-end</a>.</p>
+
+<div class='interpretation' id='start-precedes-end'> The following temporal constraint holds for any activity record: the
+<a title="activity start event">start event</a> <a>precedes</a> the <a title="activity end event">end event</a>.</div>
+-->
+
+<p>Further considerations:</p>
+<ul>
+<li>The activity identifier <span class="name">id</span> contained in an activity record is also expected to be unique among all the identifiers contained in the current account's records.
+This constraint is elaborated upon in <a href="#identifiable-record-in-account">identifiable-record-in-account</a>. It means that the current account does not contain any other record for
+this identifier, and that effectively <span class="name">id</span> acts as a <em>local</em> identifier for this record in the current account.</li>
+
+<li>An activity record is not an entity record.
+Indeed, an entity record represents an entity that exists in full at
+any point in its characterization interval, persists during this
+interval, and preserves the characteristics that makes it
+identifiable. Alternatively, an activity in something that happens,
+unfolds or develops through time, but is typically not identifiable by
+the characteristics it exhibits at any point during its duration.
+This distinction is similar to the distinction between
+'continuant' and 'occurrent' in logic [[Logic]].</li>
+</ul>
+
+
+</section>
+
+<section id="record-Agent">
+<h3>Agent Record</h3>
+
+
+
+<p>An <dfn id="dfn-Agent">agent record</dfn> is a representation of an agent, which is an entity that can be assigned some degree of responsibility for an activity taking place.</p>
+
+<p>Many agents can have an association with a given activity. An agent may do the ordering of the activity, another agent may do its design, another agent may push the button to start it,
+another agent may run it, etc.
+As many agents as one wishes to mention can occur in the provenance record, if it is important to indicate that they were associated with the activity. </p>
+
+<p>
+From an inter-operability perspective, it is useful to define some basic categories of agents since
+it will improve the use of provenance records by applications.
+There should be very few of these basic categories to keep the model simple and accessible.
+There are three types of agents in the model since they are common across most anticipated domain of use:
+<ul>
+<li><span class="name">Person</span>: agents of type Person are people. (This type is equivalent to a "foaf:person" [[FOAF]])</li>
+<li><span class="name">Organization</span>: agents of type Organization are social institutions such as companies, societies etc. (This type is equivalent to a "foaf:organization"
+[[FOAF]])</li>
+<li><span class="name">SoftwareAgent</span>: a software agent is a piece of software. </li>
+</ul>
+<p>These types are mutually exclusive, though they do not cover all kinds of agent. </p>
+
+
+<p>An agent record, noted <span class="name">agent(id, [ attr1=val1, ...])</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an identifier <span class="name">id</span> identifying an agent;</li>
+<li><em>attributes</em>: contains a set of attribute-value pairs <span class="name">[ attr1=val1, ...]</span>, representing this agent's situation in the world.</li>
+</ul>
+
+<p>In PROV-ASN, an agent record's text matches the <span class="nonterminal">agentRecord</span> production of the grammar defined in this specification document.
+</p>
+
+
+<div class='grammar'>
+<span class="nonterminal">agentRecord</span> ::=
+<span class="name">agent</span>
+<span class="name">(</span>
+<span class="nonterminal">identifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+
+
+
+<div class="anexample">
+<p>With the following assertions,</p>
+<pre class="codeexample">
+agent(e1, [ex:employee="1234", ex:name="Alice", prov:type="prov:Person" %% xsd:QName])
+
+entity(e2) and wasStartedBy(a1,e2,[prov:role="author"])
+
+entity(e3) and wasAssociatedWith(a1,e3,[prov:role="sponsor"])
+</pre>
+<p>the agent record represents an explicit agent identified by <span class="name">e1</span> that holds irrespective of activities it may be associated with. On the other hand, from the
+entity records identified by <span class="name">e2</span> and <span class="name">e3</span>, one can infer agent records, as per the following inference.</p>
+</div>
+
+<p>One can assert an agent record or alternatively, one can infer an agent record
+by its association with an activity. </p>
+
+<div class='inference' id='association-agent'>
+<span class='conditional'>If</span> the records <span class="name">entity(e,attrs)</span>
+and
+<span class="name">wasAssociatedWith(a,e)</span> hold for some identifiers
+<span class="name">a</span>, <span class="name">e</span>, and attribute-values <span class="name">attrs</span>, then
+the record <span class="name">agent(e,attrs)</span> also holds.
+</div>
+
+<div class='issue'> Shouldn't we allow for entities (not agent) to be associated with an activity? Should we drop the inference association-agent? <a
+href="http://www.w3.org/2011/prov/track/issues/203">ISSUE-203</a>.</div>
+
+</section>
+
+ <section id="record-note">
+
+<h4>Note Record</h4>
+
+<p>As provenance records are exchanged between systems, it may be useful to add extra-information about such records. For instance, a "trust service" may add value-judgements about the
+trustworthiness of some of the assertions made. Likewise, an interactive visualization component may want to enrich a set of provenance records with information helping reproduce their
+visual representation. To help with inter-operability, PROV-DM introduces a simple annotation mechanism allowing any identifiable record to be associated with notes.</p>
+
+<p>A <dfn id="dfn-note">note record</dfn> is a set of attribute-value pairs, whose meaning is application specific. It may or may not be a representation of something in the world.</p>
+
+<p>In PROV-ASN, a note record's text matches the <span class="nonterminal">noteRecord</span> production of the grammar defined in this specification document.
+</p>
+
+
+<div class='grammar'>
+<span class="nonterminal">noteRecord</span> ::=
+<span class="name">note</span>
+<span class="name">(</span>
+<span class="nonterminal">identifier</span>
+<span class="name">,</span>
+<span class="nonterminal">attribute-values</span>
+<span class="name">)</span><br/>
+<!-- -->
+</div>
+
+<p>A separate PROV-DM record is used to associate a note with an identifiable record (see <a href="#record-annotation">Section on annotation</a>). A given note may be associated with
+multiple records.
+</p>
+
+
+<div class="anexample">
+<p>
+The following note record consists of a set of application-specific attribute-value pairs, intended
+to help the rendering of the record it is associated with, by
+specifying its color and its position on the screen.</p>
+<pre class="codeexample">
+note(ann1,[ex:color="blue", ex:screenX=20, ex:screenY=30])
+hasAnnotation(g1,n1)
+</pre>
+<p>The note record is associated with a record <span class="name">g1</span> previously introduced (<a title="annotation record">hasAnnotation</a> is
+discussed in Section <a href="#record-annotation">Annotation Record</a>). In this example,
+the attribute-value pairs do not constitute a representation of something
+in the world; they are just used to help render provenance.
+</p>
+</div>
+
+<p>
+Attribute-value pairs occurring in notes differ from attribute-value pairs occurring in entity records and activity records. In entity and activity records, attribute-value pairs MUST be a
+representation of something in the world, which remain constant for the duration of the characterization interval (for entity record) or the activity duration (for activity records).
+A note record linked with an entity record consists of
+attribute-value pairs which may or may not represent the entity's
+situation in the world.
+If a note record's attribute-value pair represents an entity's situation
+in the world, no requirement is made on this situation to be unchanged for
+the entitys' characterization interval.
+</p>
+
+<div class='issue'> Comments on notes and their attributes appear in <a href="http://www.w3.org/2011/prov/track/issues/189">ISSUE-189</a>.</div>
+
+ </section>
+
+</section>
+
+
+<section id="record-relation">
+<h3>Relation</h3>
+
+<p>This section describes all the PROV-DM records representing relations between the elements introduced in <a href="#record-element">Section Element</a>. While these relations are not
+binary, they all involve two primary elements. They can be summarized as follows. </p>
+
+
+<div style="text-align: center;">
+<table border="1" style="margin-left: auto; margin-right: auto;">
+<caption>PROV-DM Core Relation Summary</caption>
+<tr><td></td><td>Entity</td><td>Activity</td><td>Agent</td><td>Note</td></tr>
+<tr><td>Entity</td><td><a title="derivation record">wasDerivedFrom</a><br><a title="alternate record">alternateOf</a><br><a title="specialization record">specializationOf</a></td><td><a
+title="generation record">wasGeneratedBy</a></td><td>—</td><td><a title="annotation record">hasAnnotation</a></td></tr>
+<tr><td>Activity</td><td><a title="usage record">used</a></td><td>—</td><td><a title="start record">wasStartedBy</a><br><a title="end record">wasEndedBy</a><br><a title="activity
+association record">wasAssociatedWith</a></td><td><a title="annotation record">hasAnnotation</a></td></tr>
+<tr><td>Agent</td><td>—</td><td>—</td><td><a title="responsibility record">actedOnBehalfOf</a></td><td><a title="annotation record">hasAnnotation</a></td></tr>
+<tr><td>Note</td><td>—</td><td>—</td><td>—</td><td><a title="annotation record">hasAnnotation</a></td></tr>
+</table>
+</div>
+
+
+<p>In PROV-ASN, all these relation records are conformant to the <span class='nonterminal'>relationRecord</span> production of the grammar.</p>
+
+<section id="activity-entity-relation">
+<h3>Activity-Entity Relation</h3>
+
+<section id="record-Generation">
+<h4>Generation Record</h4>
+
+
+<p>In PROV-DM, a <dfn id="dfn-Generation">generation record</dfn> is a representation of an instantaneous world <a title="entity generation event">event</a>, the completed creation of a new
+entity by an activity. This entity become available for usage after this <a title="event">instantaneous
+event</a>. This entity did not exist before creation (though another with a different characterization may have existed before).
+The representation of this <a title="event">instantaneous event</a> encompasses a description of the modalities of generation of this entity by this activity.</p>
+
+<p>A <a title="entity generation event">generation event</a> may be, for example, the completed creation of a file by a program, the completed creation of a linked data set, the completed
+publication of a new version of a document, and the complete sending of a value on a communication channel. The point at which creation is actually complete is application specific:
+generation of a file may complete when a lock is released by its creator, whereas actual publication of a document may be after the embargo period that was defined for it.</p>
+
+<p>A generation record, written <span class="name">wasGeneratedBy(id,e,a,t,attrs)</span> in PROV-ASN, has the following components:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the generation record;</li>
+<li><em>entity</em>: an identifier <span class="name">e</span> identifying an entity record that represents the entity that is created; </li>
+<li><em>activity</em>: an OPTIONAL identifier <span class="name">a</span> identifying an activity record that represents the activity that creates the entity;</li>
+
+<li><em>time</em>: an OPTIONAL "generation time" <span class="name">t</span>, the time at which the entity was created;</li>
+
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describes the modalities of generation of this entity by this activity.</li>
+
+</ul>
+
+<p>In PROV-ASN, a generation record's text matches the <span class='nonterminal'>generationRecord</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">generationRecord</span> ::=
+<span class="name">wasGeneratedBy</span>
+<span class="name">(</span>
+<span class="optional"> <span class="nonterminal">identifier</span>
+<span class="name">,</span> </span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="optional"><span class="nonterminal">aIdentifier</span></span>
+<span class="optional"><span class="name">,</span>
+<span class="nonterminal">time</span></span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span><br/>
+</div>
+
+
+<p>
+A generation record's id is OPTIONAL. It MUST be used when annotating generation records (see Section <a href="#record-annotation">Annotation Record</a>) or when defining precise-1
+derivations (see <a href="#Derivation-Relation">Derivation Record</a>).
+</p>
+
+
+<div class='anexample'>
+<p>
+The following generation assertions</p>
+<pre class="codeexample">
+ wasGeneratedBy(e1,a1, 2001-10-26T21:32:52, [ex:port="p1", ex:order=1])
+ wasGeneratedBy(e2,a1, 2001-10-26T10:00:00, [ex:port="p1", ex:order=2])
+</pre>
+<p>state the existence of two <a title="event">events</a> in the world (with respective times <span class="name">2001-10-26T21:32:52</span> and <span
+class="name">2001-10-26T10:00:00</span>), at which new entities, represented by entity records identified by <span class="name">e1</span> and <span class="name">e2</span>, are created by an
+activity, itself represented by an activity record identified by <span class="name">a1</span>.
+The first one is available as the first value on port p1, whereas the other is the second value on port p1. The semantics of <span class="name">port</span> and <span
+class="name">order</span> in these records are application specific.
+</p>
+</div>
+
+
+<div class='anexample'>
+<p>
+In some cases, we may want to record the time at which an entity was generated without having to specify the activity that generated it. To support this requirement, the activity component in generation records is optional. Hence, the following record indicates the time at which an entity is generated, without giving the activity that did it.</p>
+<pre class="codeexample">
+ wasGeneratedBy(e,,2001-10-26T21:32:52)
+</pre>
+</div>
+
+<p></p>
+<div class="interpretation-forward">
+For the interpretation of a generation record, see <a href="#generation-within-activity">generation-within-activity</a>.
+</div>
+
+
+
+<!--
+<p>The assertion of a generation record implies ordering of <a title="event">events</a> in the world.</p>
+
+
+<div class='interpretation' id='generation-within-activity'><span class='conditional'>If</span> an assertion <span class="name">wasGeneratedBy(x,a,attrs)</span> or <span
+class="name">wasGeneratedBy(x,a,attrs,t)</span> holds, <span class='conditional'>then</span> the following temporal constraint also holds: the <a title="entity generation
+event">generation</a> of the entity denoted by <span class="name">x</span> <a>precedes</a> the <a title="activity end event">end</a>
+of <span class="name">a</span> and <a>follows</a> the <a title="activity start event">start</a> of <span class="name">a</span>.
+</div>
+-->
+
+<p></p>
+<div class="structural-forward">
+See <a href="#generation-uniqueness">generation-uniqueness</a> for a structural constraint on generation records.
+</div>
+
+
+<!--
+<p>A given entity record can be referred to in a single generation record in the scope of a given <a href="#record-Account">account</a>.
+The rationale for this constraint is as follows.
+If two activities sequentially set different values to some attribute by means of two different <a title="entity generation event">generation events</a>, then they generate distinct
+entities. Alternatively, for two activities to generate an entity simultaneously, they would require some synchronization by which they agree the entity is released for use; the end of this
+synchronization would constitute the actual generation of the entity, but is performed by a single activity. This uniqueness constraint is formalized as follows.
+
+<div class='constraint' id='generation-uniqueness'>Given an entity record denoted by <span class="name">e</span>, two activity records denoted by <span class="name">a1</span> and <span
+class="name">a2</span>, and two sets of attribute-value pairs <span class="name">attrs1</span> and <span class="name">attrs2</span>,
+<span class='conditional'>if</span> the records <span class="name">wasGeneratedBy(e,a1,attrs1)</span> and <span class="name">wasGeneratedBy(e,a2,attrs2)</span> exist in the scope of a given
+account,
+<span class='conditional'>then</span> <span class="name">a1</span>=<span class="name">a2</span> and <span class="name">attrs1</span>=<span class="name">attrs2</span>.
+</div>
+
+<div class='note'>TODO: Introduce the well-formed-ness constraint in a entirely separate section.</div>
+-->
+
+
+<div class='pending'> We may want to assert the time at which an entity is created. The placeholder for such time information is a generation record. But a generation mandates the presence of an activity identifier. But it may not be known.
+It would be nice if the activity identifier was made optional in the generation record.
+This is <a href="http://www.w3.org/2011/prov/track/issues/205">ISSUE-205</a>.
+<em>This is now implemented. See also <a href="http://www.w3.org/2011/prov/track/issues/43">ISSUE-43</a>.</em></div>
+</section>
+
+
+<section id="record-Usage">
+<h3>Usage Record</h3>
+
+
+
+<p>In PROV-DM, a <dfn id="dfn-Use">usage record</dfn> is a representation of an instantaneous world <a title="entity usage event">event</a>: an activity beginning to consume an entity.
+Before this event, the activity had not begun to consume or use to this entity.
+ The representation includes a description of the modalities of usage of this entity by this activity.</p>
+
+<p>
+A <a title="entity usage event">usage event</a> may be a procedure beginning to consume a parameter, a service starting to read a value on a port, a program beginning to read a configuration
+file, or the point at which an ingredient, such as eggs, is being added in a baking activity. Usage may entirely consume an entity (e.g. eggs are not longer available after being added to
+the mix), or leave it as such, ready for further uses (e.g. a file on a file system can be read indefinitely).</p>
+
+
+<p>A usage record, written <span class="name">used(id,a,e,t,attrs)</span> in PROV-ASN, has the following constituent:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the usage record;</li>
+<li><em>activity</em>: an identifier <span class="name">a</span> for an activity record, which represents the consuming activity;</li>
+<li><em>entity</em>: an identifier <span class="name">e</span> for an entity record, which represents the entity that is consumed;</li>
+<li><em>time</em>: an OPTIONAL "usage time" <span class="name">t</span>, the time at which the entity was used;</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of usage of this entity by this activity;</li>
+</ul>
+
+<p>In PROV-ASN, a usage record's text matches the <span class='nonterminal'>usageRecord</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">usageRecord</span> ::=
+<span class="name">used</span>
+<span class="name">(</span>
+<span class="optional">
+<span class="nonterminal">identifier</span>
+<span class="name">,</span>
+</span>
+<span class="nonterminal">aIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="optional">
+<span class="name">,</span>
+ <span class="nonterminal">time</span>
+</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span><br/>
+</div>
+
+
+<p>
+A usage record's id is OPTIONAL, but comes handy when annotating usage records (see Section <a href="#record-annotation">Annotation Record</a>) or when defining derivations.
+</p>
+
+
+<div class='anexample'>
+<p>The following usage records</p>
+<pre class="codeexample">
+ used(a1,e1,2011-11-16T16:00:00,[ex:parameter="p1"])
+ used(a1,e2,2011-11-16T16:00:01,[ex:parameter="p2"])
+</pre>
+<p>state that the activity, represented by the activity record identified by <span class="name">a1</span>, consumed two entities, represented by entity records identified by <span
+class="name">e1</span> and <span class="name">e2</span>, at times <span class="name">2011-11-16T16:00:00</span> and <span class="name">2011-11-16T16:00:01</span>, respectively; the first
+one was found as the value of parameter <span class="name">p1</span>, whereas the second was found as value of parameter <span class="name">p2</span>. The semantics of <span
+class="name">parameter</span> in these records is application specific.</p>
+</div>
+
+
+
+
+
+<p>
+A usage record's id is OPTIONAL. It MUST be present when annotating usage records (see Section <a href="#record-annotation">Annotation Record</a>) or when defining precise-1 derivations (see
+<a href="#Derivation-Relation">Derivation Record</a>).</p>
+
+<p>
+A reference to a given entity record MAY appear in multiple usage records that share
+ a given activity record identifier.
+</p>
+
+
+<div class="interpretation-forward">
+For the interpretation of a usage record, see <a href="#generation-precedes-usage">generation-precedes-usage</a> and <a href="#usage-within-activity">usage-within-activity</a>.
+</div>
+
+
+
+</section>
+</section>
+
+
+
+
+
+<section id="activity-agent-relation">
+<h3>Activity-Agent Relation</h3>
+
+<section id="record-ActivityAssociation">
+<h4>Activity Association Record</h4>
+
+<p>The key purpose of agents in PROV-DM is to assign responsibility
+for activities. It is important to reflect that there is a degree in
+the responsibility of agents, and that is a major reason for
+distinguishing among all the agents that have some association with an
+activity and determine which ones are really the originators of the
+entity. For example, a programmer and a researcher could both be
+associated with running a workflow, but it may not matter what
+programmer clicked the button to start the workflow while it would
+matter a lot what researcher told the programmer to do so. Another
+example: a student publishing a web page describing an academic
+department could result in both the student and the department being
+agents associated with the activity, and it may not matter what
+student published a web page but it matters a lot that the department
+told the student to put up the web page. So there is some notion of
+responsibility that needs to be captured. </p>
+
+<p>Examples of activity association include designing, participation, initiation and termination, timetabling or sponsoring. </p>
+
+
+<p>Provenance reflects activities that have occurred. In some
+cases, those activities reflect the execution of a plan that was
+designed in advance to guide the execution. PROV-DM allows attaching
+a plan to an activity record, which represents what was intended to
+happen. The plan can be useful for various tasks, for example to
+validate the execution as represented in the provenance record, to
+manage expectation failures, or to provide explanations.</p>
+
+
+
+
+<p>In the context of PROV-DM, a <dfn>plan</dfn> should be understood as the description of a set of
+actions or steps intended by one or more agents to achieve some goal. PROV-DM is not
+prescriptive about the nature of plans, their representation, the
+actions and steps they consist of, and their intended goals. Hence,
+for the purpose of this specification, a plan can be a workflow for a
+scientific experiment, a recipe for a cooking activity, or a list of
+instructions for a micro-processor execution. While PROV-DM does not
+specify the representations of plans, it allows for activities to be
+associated with plans. Furthermore, since plans may evolve over time,
+it may become necessary to track their provenance, and hence, plans are
+entities. An activity MAY be associated with multiple plans. This
+allows for descriptions of activities initially associated with a
+plan, which was changed, on the fly, as the activity progresses. Plans
+can be successfully executed or they can fail. We expect applications
+to exploit PROV-DM <a href="#extensibility-section">extensibility
+mechanisms</a> to capture the rich nature of plans and associations
+between activities and plans.</p>
+
+
+<p>Thus, PROV-DM offers two kinds of records. The first, introduced in this section, represents an association between an agent, a plan, and an activity; the second, introduced in <a
+href="#record-responsibility">Section Responsibility record</a>, represents the fact that an agent was acting on behalf of another, in the context of an activity. </p>
+
+
+<p>An <dfn id="dfn-activity-association">activity association record</dfn>, written <span class="name">wasAssociatedWith(id,a,ag2,pl,attrs)</span> in PROV-ASN, has the following
+constituents:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the activity association record;</li>
+<li><em>activity</em>: an identifier <span class="name">a</span> for an activity record;</li>
+<li><em>agent</em>: an identifier <span class="name">ag2</span> for an agent record, which represents the agent associated with the activity;</li>
+<li><em>plan</em>: an OPTIONAL identifier <span class="name">pl</span> for an entity record, which represents a plan adopted by the agent in the context of this activity;
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of association of this activity with this agent.</li>
+</ul>
+
+<p>In PROV-ASN, an activity association record's text matches the <span class="nonterminal">activityAssociationRecord</span> productions of the grammar defined in this specification
+document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">activityAssociationRecord</span> ::=
+<span class="name">wasAssociatedWith</span>
+<span class="name">(</span>
+<span class="optional"><span class="nonterminal">identifier</span>,</span>
+<span class="nonterminal">aIdentifier</span>,
+<span class="nonterminal">agIdentifier</span>
+<span class="optional">,<span class="nonterminal">eIdentifier</span></span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<div class="anexample">
+In the following example, a designer and an operator agents are asserted to be associated with an activity. The designer's goals are achieved by a workflow <span class="name">ex:wf</span>.
+<pre class="codeexample">
+activity(ex:a,[prov:type="workflow execution"])
+agent(ex:ag1,[prov:type="operator"])
+agent(ex:ag2,[prov:type="designer"])
+wasAssociatedWith(ex:a,ex:ag1,[prov:role="loggedInUser", ex:how="webapp"])
+wasAssociatedWith(ex:a,ex:ag2,ex:wf,[prov:role="designer", ex:context="project1"])
+entity(ex:wf,[prov:type="prov:Plan"%% xsd:QName, ex:label="Workflow 1",
+ ex:url="http://example.org/workflow1.bpel" %% xsd:anyURI])
+</pre>
+Since the workflow <span class="name">ex:wf</span> is itself an entity, its provenance can also be expressed in PROV-DM: it can be generated by some activity and derived from other entities,
+for instance.
+</div>
+
+<div class='issue'> The activity association record does not allow for a plan to be asserted without an agent.
+This seems over-restrictive. Discussed in the context of <a href="http://www.w3.org/2011/prov/track/issues/203">ISSUE-203</a>.</div>
+
+
+<div class='issue'> Agents should not be inferred. WasAssociatedWith should also work with entities.
+This is <a href="http://www.w3.org/2011/prov/track/issues/206">ISSUE-206</a>.</div>
+
+
+</section>
+
+<section id="record-Start-End">
+<h4>Start and End Records</h4>
+
+<p> A <dfn id="dfn-Start">start record</dfn> is a representation of an agent starting an activity.
+ An <dfn id="dfn-End">end record</dfn> is a representation of an agent ending an activity. Both relations are specialized forms of <span class="name">wasAssociatedWith</span>. They contain
+attributes describing the modalities of acting/ending activities.</p>
+
+
+
+<p>A start record, written <span class="name">wasStartedBy(id,a,ag,attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the start record;</li>
+<li><em>activity</em>: an identifier <span class="name">a</span> denoting an activity record, representing the started activity;
+<li><em>agent</em>: an identifier <span class="name">ag</span> for an agent record, representing the starting agent;
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span>, describing modalities according to which the agent started the activity.
+</ul>
+
+<p>An end record, written <span class="name">wasEndedBy(id,a,ag,attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the end record;</li>
+<li><em>activity</em>: an identifier <span class="name">a</span> denoting an activity record, representing the ended activity;
+<li><em>agent</em>: an identifier <span class="name">ag</span> for an agent record, representing the ending agent;
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span>, describing modalities according to which the agent ended the activity.
+</ul>
+
+<p>In PROV-ASN, start and end record's texts match the <span class="nonterminal">startRecord</span> and <span class="nonterminal">endRecord</span> productions of the grammar defined in this
+specification document.
+</p>
+
+
+<div class='grammar'>
+<span class="nonterminal">startRecord</span> ::=
+<span class="name">wasStartedBy</span>
+<span class="name">(</span>
+<span class="optional"> <span class="nonterminal">identifier</span>,</span>
+<span class="nonterminal">aIdentifier</span>,
+<span class="nonterminal">agIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span><br/>
+<span class="nonterminal">endRecord</span> ::=
+<span class="name">wasEndedBy</span>
+<span class="name">(</span>
+<span class="optional"> <span class="nonterminal">identifier</span>,</span>
+<span class="nonterminal">aIdentifier</span>,
+<span class="nonterminal">agIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+
+<div class="anexample">
+<p>
+The following assertions</p>
+<pre class="codeexample">
+wasStartedBy(a,ag,[ex:mode="manual"])
+wasEndedby(a,ag,[ex:mode="manual"])
+</pre>
+<p>state that the activity, represented by the activity record denoted by <span class="name">a</span>
+was started and ended by an agent, represented by record denoted by <span class="name">ag</span>, in "manual" mode, an application specific characterization of these relations.
+</p>
+</div>
+
+<div class='issue'>
+Should we define start/end records as representation of activity start/end events.
+Should time be associated with these events rather than with activities. This will be similar to what
+we do for entities. This is issue <a href="http://www.w3.org/2011/prov/track/issues/207">ISSUE-207</a>.</div>
+
+
+</section>
+
+
+
+
+</section>
+
+<section id="entity-entity-agent-agent-relation">
+<h4>Entity-Entity or Agent-Agent Relation</h4>
+
+<section id="record-responsibility">
+
+<h4>Responsibility Record</h4>
+
+<p>To promote take-up, PROV-DM offers a mild version of responsibility
+in the form of a relation to represent when an agent acted on another
+agent's behalf. So in the example of someone running a mail program,
+the program is an agent of that activity and the person is also an
+agent of the activity, but we would also add that the mail software
+agent is running on the person's behalf. In the other example, the
+student acted on behalf of his supervisor, who acted on behalf of the
+department chair, who acts on behalf of the university, and all those
+agents are responsible in some way for the activity to take place but
+we don't say explicitly who bears responsibility and to what
+degree. </p>
+
+<p>We could also say that an agent can act on behalf of several other
+agents (a group of agents). This would also make possible to
+indirectly reflect chains of responsibility. This also indirectly
+reflects control without requiring that control is explicitly
+indicated. In some contexts there will be a need to represent
+responsibility explicitly, for example to indicate legal
+responsibility, and that could be added as an extension to this core
+model. Similarly with control, since in particular contexts there
+might be a need to define specific aspects of control that various
+agents exert over a given activity.</p>
+
+<p>Given an activity association record <span class="name">wasAssociatedWith(a,ag2,attrs)</span>,
+a <dfn id="dfn-responsibility">responsibility record</dfn>, written <span class="name">actedOnBehalfOf(id,ag2,ag1,a,attrs)</span> in PROV-ASN, has the following constituents:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the responsibility record;</li>
+<li><em>subordinate</em>: an identifier <span class="name">ag2</span> for an agent record, which represents an agent associated with an activity, acting on behalf of the responsible
+agent;</li>
+<li><em>responsible</em>: an identifier <span class="name">ag1</span> for an agent record, which represents the agent on behalf of which the subordinate agent <span class="name">ag2</span>
+acts;</li>
+<li><em>activity</em>: an OPTIONAL identifier <span class="name">a</span> of an activity record for which the responsibility record holds;</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this relation.</li>
+</ul>
+
+
+<div class='grammar'>
+<span class="nonterminal">responsibilityRecord</span> ::=
+<span class="name">actedOnBehalfOf</span>
+<span class="name">(</span>
+<span class="optional"> <span class="nonterminal">identifier</span>,</span>
+<span class="nonterminal">agIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">agIdentifier</span>
+<span class="name">,</span>
+<span class="optional"><span class="nonterminal">aIdentifier</span></span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<div class="anexample">
+In the following example, a programmer, a researcher and a funder agents are asserted. The programmer and researcher are associated with a workflow activity. The programmer acts on behalf
+of the researcher (delegation) encoding the commands specified by the researcher; the researcher acts on behalf of the funder, who has an contractual agreement with the researcher. The terms
+'delegation' and 'contact' used in this example are domain specific.
+<pre class="codeexample">
+activity(a,[prov:type="workflow"])
+agent(ag1,[prov:type="programmer"])
+agent(ag2,[prov:type="researcher"])
+agent(ag3,[prov:type="funder"])
+wasAssociatedWith(a,ag1,[prov:role="loggedInUser"])
+wasAssociatedWith(a,ag2)
+actedOnBehalfOf(ag1,ag2,a,[prov:type="delegation"])
+actedOnBehalfOf(ag2,ag3,a,[prov:type="contract"])
+</pre>
+</div>
+
+
+</section>
+
+<section id="Derivation-Relation">
+<h4>Derivation Record</h4>
+
+<p>In PROV-DM, a <dfn id="dfn-Derivation">derivation record</dfn> is a representation that some entity is transformed from, created from, or affected by another entity in the world. </p>
+
+
+<p>Examples of derivation include the transformation of a canvas into a painting, the transportation of a person from London to New York, the transformation of a relational table into a
+linked data set, and the melting of ice into water.</p>
+
+
+<p>According to <a href="#conceptualization">Section Conceptualization</a>, for an entity to be transformed from, created from, or affected by another in some way, there must be some
+underpinning activities performing the necessary actions resulting in such a derivation.
+However, asserters may not assert or have knowledge of these activities and associated details: they may not assert or know their number, they may not assert or know their identity, they may
+not assert or know the attributes characterizing how the relevant entities are used or generated. To accommodate the varying circumstances of the various asserters, PROV-DM allows more or
+less precise records of derivation to be asserted. Hence, PROV-DM uses the terms <em>precise</em> and <em>imprecise</em> to characterize the different kinds of derivation record. We note
+that the derivation itself is exact (i.e., deterministic, non-probabilistic), but it is its description, expressed in a derivation record, that may be imprecise. </p>
+
+<p>The lack of precision may come from two sources:</p>
+<ul>
+<li> the number of activities that underpin a derivation is not asserted or known, or</li>
+<li> any of the other details that are involved in the derivation is not asserted or known; these include activity identities, generation and usage records, and their attributes.</li>
+</ul>
+
+
+<!--
+Furthermore, assuming that an asserter has full knowledge of an activity underpinning a derivation, the same activity can generally be modelled in terms of sub-activities, composed in a such
+a way as to deliver the same behavior. Hence, since activities can be modelled at arbitrary levels of granularity, there is a distinguished case in which a derivation between two entities
+<span class="name">e2</span> and <span class="name">e1</span> corresponds <em>exactly</em> to <em>one</em> activity that used <span class="name">e1</span> and generated <span
+class="name">e2</span>. This is to be contrasted to the case where one derivation corresponds to n activities, where n can be any number greater than 1.
+Hence, PROV-DM uses the terms <em>one-activity</em> and <em>n-activities</em> to distinguish these two cases.</p>
+-->
+
+
+<p>Hence, we can consider two axis. An activity number axis that has values <em>single</em>, <em>multiple</em>, and <em>unknown</em>, respectively representing the case where one activity
+is known to have occurred, more than one activities are known to have occurred, or an unknown number of activities have occurred. Likewise, we can consider another axis to cover other
+details (identities, generation and usage records, attributes), with values <em>asserted</em> and <em>not asserted</em>. We can then form a matrix of possible derivations. Out of the six
+possibilities,
+PROV-DM offers three forms of derivation derivation records to cater for five othem, while the remaining one is not meaningful. The following table summarises names for the three kinds of
+derivation, which we then explain.</p>
+
+<div style="text-align: center;">
+<table border="1" style="margin-left: auto; margin-right: auto;">
+<caption>PROV-DM Derivation Type Summary</caption>
+<tr><td colspan=2 rowspan=2></td><td colspan=2><em>other details</em> axis</td></tr>
+<tr><td>asserted</td><td>not asserted</td></tr>
+<tr><td rowspan=3><em>activity number</em><br>axis</td><td>single</td><td><a>precise-1 derivation record</a></td><td><a>imprecise-1 derivation record</a></td></tr>
+<tr><td>multiple</td><td><a>imprecise-n derivation record</a></td><td rowspan=2><a>imprecise-n derivation record</a></td></tr>
+<tr><td>unknown</td><td>—</td></tr>
+</table>
+</div>
+
+<ul>
+<li> The asserter asserts that derivation is due to exactly one activity, and all the details are asserted. We call this a precise-1 derivation record.</li>
+<li> The asserter asserts that derivation is due to exactly one activity, but other details, whether known or unknown, are not asserted. We call this an imprecise-1 derivation record.</li>
+<li> The following cases are captured by an imprecise-n derivation record.
+<ul>
+<li> The asserter knows that multiple activities are involved or ignores the number of activities involved in the derivation, and other details are not asserted. </li>
+<li> The asserter knows that multiple activities are involved in the derivation, and all their details are asserted. In this case, these activities are connected by means of generated and
+used intermediary entities. Despite all activities and details being known, there is no guarantee that any of these activities plays an active role in the derivation; hence, this case is
+also regarded as imprecise. Instead, precise derivations need to be expressed between these intermediary entities. </li>
+</ul>
+</ul>
+
+<p> We note that the last theoretical cases cannot occur, since
+ asserting the details of an unknown number of activities is a contradiction.
+</p>
+
+<p>In order to represent the number of activities in a derivation, we introduce a PROV-DM attribute <span class="name">steps</span>, which can take two possible values: <span
+class="name">single</span> and <span class="name">any</span>.
+When <span class="name">prov:steps="single"</span>, derivation is due to one activity; when <span class="name">prov:steps="any"</span>, the number of activities is multiple or not known.</p>
+
+
+<p>The three kinds of derivation records are successively introduced. Making use of the attribute <span class="name">steps</span>, we can distinguish the various derivation types.</p>
+
+<p>A <dfn>precise-1 derivation record</dfn>, written <span class="name">wasDerivedFrom(id, e2, e1, a, g2, u1, attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the derivation record;</li>
+<li><em>generatedEntity</em>: the identifier <span class="name">e2</span> of an entity record, which is a representation of the generated entity;</li>
+<li><em>usedEntity</em>: the identifier <span class="name">e1</span> of an entity record, which is a representation of the used entity;</li>
+<li><em>activity</em>: an identifier <span class="name">a</span> of an activity record, which is a representation of the activity using and generating the above entities;</li>
+<li><em>generation</em>: an identifier <span class="name">g2</span> of the generation record pertaining to <span class="name">e2</span> and <span class="name">a</span>;</li>
+<li><em>usage</em>: an identifier <span class="name">u1</span> of the usage record pertaining to <span class="name">e1</span> and <span class="name">a</span>.</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation, optionally including the attribute-value
+pair <span class="name">prov:steps="single"</span>.</li>
+</ul>
+<p>It is OPTIONAL to include the attribute <span class="name">prov:steps</span> in a precise-1 derivation since the record already refers to the one and only one activity underpinning the
+derivation.</p>
+
+
+<p>An <dfn>imprecise-1 derivation record</dfn>, written <span class="name">wasDerivedFrom(id, e2,e1, t, attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the derivation record;</li>
+<li><em>generatedEntity</em>: the identifier <span class="name">e2</span> of an entity record, which is a representation of the generated entity;</li>
+<li><em>usedEntity</em>: the identifier <span class="name">e1</span> of an entity record, which is a representation of the used entity;</li>
+<li><em>time</em>: an OPTIONAL "generation time" <span class="name">t</span>, the time at which the entity denoted by <span class="name">e2</span> was created;</li>
+<li><em>attributes</em>: a set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation; it MUST include the attribute-value pair <span class="name">prov:steps="single"</span>.</li>
+</ul>
+<p>An imprecise-1 derivation MUST include the attribute <span class="name">prov:steps</span>, since it is the only means to distinguish this record from an imprecise-n derivation
+record.</p>
+
+
+<p>An <dfn>imprecise-n derivation record</dfn>, written <span class="name">wasDerivedFrom(id, e2, e1, t, attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the derivation record;</li>
+<li><em>generatedEntity</em>: the identifier <span class="name">e2</span> of an entity record, which is a representation of the generated entity;</li>
+<li><em>usedEntity</em>: the identifier <span class="name">e1</span> of an entity record, which is a representation of the used entity;</li>
+<li><em>time</em>: an OPTIONAL "generation time" <span class="name">t</span>, the time at which the entity denoted by <span class="name">e2</span> was created;</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation; it optionally includes the attribute-value pair <span class="name">prov:steps="any"</span>.</li>
+</ul>
+<p>It is OPTIONAL to include the attribute <span class="name">prov:steps</span> in an imprecise-n derivation record. It defaults to <span class="name">prov:steps="any"</span>.</p>
+
+
+<p>None of the three kinds of derivation is defined to be transitive. Domain-specific specializations of these derivations may be defined in such a way that the transitivity property
+holds.</p>
+
+
+<p>In PROV-ASN, a derivation record's text matches the <span class='nonterminal'>derivationRecord</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">derivationRecord</span> ::=
+<span class="name">wasDerivedFrom</span>
+<span class="name">(</span>
+<span class="optional"> <span class="nonterminal">identifier</span>,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">aIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">gIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">uIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span><br/>
+|
+<span class="name">wasDerivedFrom</span>
+<span class="name">(</span>
+<span class="optional"> <span class="nonterminal">identifier</span>,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="optional"><span class="name">,</span>
+<span class="nonterminal">time</span></span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+<p>
+The first clause of the alternative, where the activity, generation and usage record identifiers are present formalizes a derivation record is precise-1. The second clause of the alternative, with optional time formalizes imprecise records. The distinction between imprecise-1 and imprecise-n is made by the
+attribute <span class="name">prov:steps</span>.
+</p>
+
+<div class="anexample">
+<p>The following assertions state the existence of derivations.</p>
+<pre class="codeexample">
+wasDerivedFrom(e5,e3,a4,g2,u2)
+wasDerivedFrom(e5,e3,a4,g2,u2,[prov:steps="single"])
+
+wasDerivedFrom(e3,e2,[prov:steps="single"])
+
+wasDerivedFrom(e2,e1,[])
+wasDerivedFrom(e2,e1,[prov:steps="any"])
+
+wasDerivedFrom(e2,e1,2012-01-18T16:00:00, [prov:steps="any"])
+</pre>
+<p>
+The first two are precise-1 derivation records expressing that the activity represented by the activity <span class="name">a4</span>, by
+using the entity denoted by <span class="name">e3</span> according to usage record <span class="name">u2</span>
+ derived the
+entity denoted by <span class="name">e5</span> and generated it according to generation record
+ <span class="name">g2</span>.
+
+
+The third record is an imprecise-1 derivation, which is similar for <span class="name">e3</span> and <span class="name">e2</span>, but it leaves the activity record and associated attributes implicit. The fourth and fifth records are imprecise-n derivation records between <span class="name">e2</span> and <span class="name">e1</span>, but no information is provided as to the number and identity of activities underpinning the derivation. The six derivation records extends the fifth with the derivation time of <span class="name">e2</span>.
+</p>
+</div>
+
+
+<p>An precise-1 derivation record is richer than an imprecise-1 derivation record, itself, being more informative that an imprecise-n derivation record. Hence, the following implications
+hold.</p>
+<div class='inference' id='derivation-implications'>
+Given two entity records denoted by <span class="name">e1</span> and <span class="name">e2</span>, <span class='conditional'>if</span> the assertion <span class="name">wasDerivedFrom(e2,
+e1, a, g2, u1, attrs)</span>
+ holds for some generation record identified by <span class="name">g2</span>, and usage record identified by <span class="name">u1</span>, then <span
+class="name">wasDerivedFrom(e2,e1,[prov:steps="single"] ∪ attrs)</span> also holds.<br>
+
+Given two entity records denoted by <span class="name">e1</span> and <span class="name">e2</span>, <span class='conditional'>if</span> the assertion <span class="name">wasDerivedFrom(e2,
+e1, [prov:steps="single"] ∪ attrs)</span>
+ holds, then <span class="name">wasDerivedFrom(e2,e1,attrs)</span> also holds.<br>
+ </div>
+
+<div class="interpretation-forward">
+For the interpretation of a derivation record, see <a href="#derivation-usage-generation-ordering">derivation-usage-generation-ordering</a> and <a
+href="#derivation-generation-generation-ordering">derivation-generation-generation-ordering</a>
+</div>
+
+<!--
+<p>
+<p>If a derivation record holds for <span class="name">e2</span> and <span class="name">e1</span>, then
+this means that the entity represented by entity record identified by <span class="name">e1</span> has an influence on the entity represented entity record identified by <span
+class="name">e2</span>,
+ which at the minimum implies temporal ordering, specified as follows.
+First, we consider one-activity derivations.</p>
+
+<div class='interpretation' id='derivation-usage-generation-ordering'>Given an activity record identified by <span class="name">a</span>, entity records identified by <span
+class="name">e1</span> and <span class="name">e2</span>, generation record identified by <span class="name">g2</span>, and usage record identified by <span class="name">u1</span>, <span
+class='conditional'>if</span> the record <span class="name">wasDerivedFrom(e2,e1,a,g2,u1,attrs)</span>
+or <span class="name">wasDerivedFrom(e2,e1,[prov:steps="single"] ∪ attrs)</span> holds, <span class='conditional'>then</span>
+the following temporal constraint holds:
+the <a title="entity usage event">usage</a>
+of entity denoted by <span class="name">e1</span> <a>precedes</a> the <a title="entity generation event">generation</a> of
+the entity denoted by <span class="name">e2</span>.
+</div>
+
+<p>Then, imprecise-n derivations.</p>
+
+<div class='interpretation' id='derivation-generation-generation-ordering'>
+Given two entity records denoted by <span class="name">e1</span> and <span class="name">e2</span>, <span class='conditional'>if</span> the record <span
+class="name">wasDerivedFrom(e2,e1,[prov:steps="n"] ∪ attrs)</span>
+ holds, <span class='conditional'>then</span> the following temporal constraint holds:
+the <a title="entity generation event">generation event</a> of the entity denoted by <span class="name">e1</span> <a>precedes</a> the <a title="entity generation event">generation event</a>
+of
+the entity denoted by <span class="name">e2</span>.
+ </div>
+
+<p>Note that temporal ordering is between generations of <span class="name">e1</span>
+and <span class="name">e2</span>, as opposed to precise-1 derivation,
+which implies temporal ordering between the usage of <span class="name">e1</span> and
+generation of <span class="name">e2</span>. Indeed, in the case of
+imprecise-n derivation, nothing is known about the usage of <span class="name">e1</span>,
+since there is no associated activity.</p>
+
+-->
+
+
+<p>The imprecise-1 derivation has the same meaning as the precise-1
+ derivation, except that an activity
+ is known to exist, though it does not need to be
+asserted. This is formalized by the following inference rule,
+referred to as <em>activity introduction</em>:</p>
+<div class='inference' id="activity-introduction">
+<span class='conditional'>If</span> <span class="name">wasDerivedFrom(e2,e1)</span> holds, <span class='conditional'>then</span> there exist an activity record identified by <span
+class="name">a</span>, a usage record identified by <span class="name">u</span>, and a generation record identified by <span class="name">g</span>
+such that:
+<pre class="codeexample">
+activity(a,aAttrs)
+wasGeneratedBy(g,e2,a,gAttrs)
+used(u,a,e1,uAttrs)
+</pre>
+for sets of attribute-value pairs <span class="name">gAttrs</span>, <span class="name">uAttrs</span>, and <span class="name">aAttrs</span>.
+</div>
+
+
+
+
+
+<p>
+Note that inferring derivation from usage and generation does not hold
+in general. Indeed, when a generation <span class="name">wasGeneratedBy(g, e2, a, attrs2)</span>
+<a>precedes</a> <span class="name">used(u, a, e1, attrs1)</span>, for
+some <span class="name">e1</span>, <span class="name">e2</span>, <span class="name">attrs1</span>, <span class="name">attrs2</span>, and <span class="name">a</span>, one
+cannot infer derivation <span class="name">wasDerivedFrom(e2, e1, a, g, u)</span>
+or <span class="name">wasDerivedFrom(e2,e1)</span> since
+of <span class="name">e2</span> cannot possibly be derived from
+ <span class="name">e1</span>, given the creation of <span class="name">e2</span> <a>precedes</a> the use
+of <span class="name">e1</span>.
+</p>
+
+
+<p>In PROV-DM, the effective placeholder for an entity generation time is the <a>generation record</a>. The presence of
+time information in imprecise derivation records is merely a convenience notation for a timeless derivation record and a generation record with this generation time information. </p>
+
+<div class='inference' id="derivation-time-elimination">
+<span class='conditional'>If</span> <span class="name">wasDerivedFrom(e2,e1,t,attrs)</span> holds, <span class='conditional'>then</span> the following records also hold:
+<span class="name">wasDerivedFrom(e2,e1,attrs)</span> and <span class="name">wasGeneratedBy(e2,t)</span>.
+</div>
+
+<p></p>
+<div class="structural-forward">
+See <a href="#derivation-use">derivation-use</a> for a structural constraint on derivation records.
+</div>
+
+
+
+
+<div class='pending'>Should derivation have a time? Which time? This is <a href="http://www.w3.org/2011/prov/track/issues/43">ISSUE-43</a>.<em>This is now addressed in this text. Optional time in derivation is generation time. See also <a href="http://www.w3.org/2011/prov/track/issues/205">ISSUE-205</a>.</em></div>
+
+
+<div class='issue'>Several points were raised about the attribute steps.
+Its name, its default value <a href="http://www.w3.org/2011/prov/track/issues/180">ISSUE-180</a>.
+ <a href="http://www.w3.org/2011/prov/track/issues/179">ISSUE-179</a>.</div>
+
+<div class='issue'> Emphasize the notion of 'affected by' <a href="http://www.w3.org/2011/prov/track/issues/133">ISSUE-133</a>.</div>
+
+
+</section>
+
+
+<section id="record-alternate-specialization">
+
+<h4>Alternate and Specialization Records</h4>
+
+<div class="note">This section is currently under revision and in flux</div>
+
+The purpose of the record types defined in this section is to establish a relationship between two entities, which asserts that they provide a different characterization of the same thing.
+Consider for example three entities:
+<ul>
+
+ <li><span class="name">e1</span> denoting "Bob, the holder of facebook account ABC",
+
+ <li><span class="name">e2</span> denoting "Bob, the holder of twitter account XYZ",
+
+ <li><span class="name">e3</span> denoting "Bob, the person".
+</ul>
+
+One may make several assertions to establish that these entities refer to the same the real-world thing Bob, either in different contexts, or at different levels of abstraction. For example:
+
+<ol>
+ <li> Entity denoted by <span class="name">e1</span> provides a <em>more concrete</em> characterization of Bob than <span class="name">e3</span> does;
+ <li> Entity denoted by <span class="name">e2</span> provides a <em>more concrete</em> characterization of Bob than <span class="name">e3</span> does;
+ <li> The entities denoted by <span class="name">e1</span> and <span class="name">e2</span> provide two different characterizations of the same thing, i.e., Bob.
+</ol>
+
+Two relations are introduced to express these assertions:
+
+<ul>
+
+ <li> e2 is a <em>specialization</em> of e1, written <span class="name">specializationOf(e2,e1)</span> captures the intent of assertion (1) and (2);
+ <li> e2 is an <em>alternative characterization</em> of e1, written <span class="name">alternateOf(e2,e1)</span> captures the intent of assertion (3).
+
+ </ul>
+
+In order to further convey the intended meaning, the following properties are associated to these two relations.
+
+ <ul>
+ <li><span class="name">specializationOf(e2,e1)</span> is <strong>transitive</strong>: <span class="name">specializationOf(e3,e2)</span> and <span
+class="name">specializationOf(e2,e1)</span> implies <span class="name">specializationOf(e3,e1)</span>.
+
+ <li><span class="name">specializationOf(e2,e1)</span> is <strong>anti-symmetric</strong>: <span class="name">specializationOf(e2,e1)</span> implies that <span
+class="name">specializationOf(e1,e2)</span> does not hold.
+ <li><span class="name">alternateOf(e2,e1)</span> is <strong>symmetric</strong>: <span class="name">alternateOf(e2,e1)</span> implies <span class="name">alternateOf(e1,e2)</span>.
+ </ul>
+
+ <div class="note">There are proposals to make alternateOf a transitive property. This is still under discussion and the default is for alternateOf <strong>not</strong> to be transitive, and this is what the current text reflects.</div>
+
+<p>A <dfn id="dfn-Alternate">alternate record</dfn>, written alternateOf(alt1, alt2, attrs) in PROV-ASN, has the following constituents:</p>
+
+<ul>
+<li><em>first alternate</em>: an identifier <span class="name">alt1</span> of the first of the two entities</li>
+<li><em>second alternate</em>: an identifier <span class="name">alt2</span> of the second of the two entities</li>
+<li><em>attrs</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+
+<p>A <dfn id="dfn-Specialization">specialization record</dfn> written specializationOf(sub, super, attrs) in PROV-ASN, has the following constituents:</p>
+
+<ul>
+<li><em>specialised entity</em>: an identifier <span class="name">sub</span> of the specialised entity</li>
+<li><em>general entity</em>: an identifier <span class="name">super</span> of the entity that is being specialised</li>
+<li><em>attrs</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+
+
+<p>
+An entity record identifier can optionally be accompanied by an account identifier. When this is the case, it becomes possible to use the <span class="name">alternateOf</span> relation to
+link two entity record identifiers that are appear in different accounts. (In particular, the entity identifiers in two different account are allowed to be the same.). When account
+identifiers are not available, then the linking of entity records through <span class="name">alternateOf</span> can only take place within the scope of a single account.
+</p>
+
+
+
+<p>In PROV-ASN, an alternate record's text matches the <span class="nonterminal">alternateRecord</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+ <span class="nonterminal">alternateRecord</span> ::=
+ <span class="name">alternateOf</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span> <br/>
+|
+ <span class="name">alternateOf</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+ <span class="nonterminal">accIdentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+ <span class="nonterminal">accIdentifier</span>
+<span class="name">,</span>
+ <span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<p>In PROV-ASN, a specialization record's text matches the <span class="nonterminal">specializationRecord</span>production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+ <span class="nonterminal">specializationRecord</span> ::=
+ <span class="name">specializationOf</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span> <br/>
+|
+ <span class="name">specializationOf</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+ <span class="nonterminal">accIdentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+ <span class="nonterminal">accIdentifier</span>
+<span class="name">,</span>
+ <span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span> <br/>
+
+</div>
+
+
+<div class='issue'>A discussion on alternative definition of these relations has not reached a satisfactory conclusion yet. This is <a
+href="http://www.w3.org/2011/prov/track/issues/29">ISSUE-29</a>. Also <a href="http://www.w3.org/2011/prov/track/issues/96">ISSUE-96</a>.</div>
+
+
+</section>
+</section>
+
+
+
+<!--
+<section>
+<h4>Transitive Derivation Record</h4>
+
+
+<p>
+If <span class="name">wasDerivedFrom(e2,e1)</span> holds because attribute <span class="name">a2.1</span> of <span class="name">e2</span> is determined by attribute <span
+class="name">a1.1</span> of <span class="name">e1</span>,
+and if <span class="name">wasDerivedFrom(e3,e2)</span> holds because attribute <span class="name">a3.1</span>of <span class="name">e3</span> is determined by attribute <span
+class="name">a2.2</span> of <span class="name">e1</span>, it is not necessarily the case that an attribute of <span class="name">e3</span> is determined by an attribute of <span
+class="name">e1</span>; so, an asserter may not be able to assert <span class="name">wasDerivedFrom(e3,e1)</span>, since it would fail to satisfy constraint <a
+href="#derivation-attributes">derivation-attributes</a>. Hence, the constraint on attributes as expressed in <a href="#derivation-attributes">derivation-attributes</a> invalidates
+transitivity in the general case.
+</p>
+
+<p>However, there is sense that <span class="name">e3</span> still depends on <span class="name">e1</span>, since <span class="name">e3</span> could not be generated without <span
+class="name">e1</span> existing. Hence, we introduce a weaker notion of derivation record, which is transitive.</p>
+
+A transitive derivation record, written <span class="name">dependedOn(e2, e1)</span> in PROV-ASN:
+<ul>
+<li> contains an identifier <span class="name">e2</span>, denoting an entity record, which represents the entity that is the result of the derivation;
+<li> contains an identifier <span class="name">e1</span>, denoting an entity record, which represents the entity that the derivation relies upon.
+</ul>
+<p>The record <span class="name">dependedOn</span> can only be inferred; in other words, it cannot be asserted. It is
+transitive by definition and relies on the previously defined derivation assertions for its
+base case.</p>
+
+<div class='constraint' id='transitive-derivation'>
+<ul>
+<li><span class='conditional'>If</span> <span class="name">wasDerivedFrom(e2,e1)</span> or <span class="name">wasDerivedFrom(e2,e1,pe,attrs2,attrs1)</span> holds, <span
+class='conditional'>then</span> <span class="name">dependedOn(e2,e1)</span> holds.</li>
+<li><span class='conditional'>If</span> <span class="name">wasEventuallyDerivedFrom(e2,e1)</span> holds, <span class='conditional'>then</span> <span class="name">dependedOn(e2,e1)</span>
+holds.</li>
+<li><span class='conditional'>If</span> <span class="name">dependedOn(e3,e2)</span> and <span class="name">dependedOn(e2,e1)</span> hold, <span class='conditional'>then</span> <span
+class="name">dependedOn(e3,e1)</span> holds.</li>
+</ul>
+</div>
+
+</section>
+-->
+
+
+
+
+
+
+
+<section id="record-annotation">
+<h4>Annotation Record</h4>
+
+
+<p>An <dfn id="dfn-annotation">annotation record</dfn> establishes a link between an identifiable PROV-DM record and a note record referred to by its identifier. Multiple note records can
+be associated with a given PROV-DM record; symmetrically, multiple PROV-DM records can be associated with a given note record. Since note records have identifiers, they can also be
+annotated. The annotation mechanism (with note record and the annotation record) forms a key aspect of the extensibility mechanism of PROV-DM (see <a
+href="#extensibility-section">extensibility section</a>).</p>
+
+<p>An annotation record, written <span class="name">hasAnnotation(r,n,attrs)</span> in PROV-ASN, has the following constituents:</p>
+<ul>
+<li><em>record</em>: an identifier <span class="name">r</span> of the record being annnotated;</li>
+<li><em>note</em>: an identifier <span class="name">n</span> of a note record;</li>
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+
+<p>In PROV-ASN, a note record's text matches the <span class="nonterminal">noteRecord</span> production of the grammar defined in this specification document.
+</p>
+
+<div class='grammar'>
+<span class="nonterminal">annotationRecord</span> ::=
+<span class="name">hasAnnotation</span>
+<span class="name">(</span>
+<span class="nonterminal">identifier</span>
+<span class="name">,</span>
+<span class="nonterminal">nIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<p>The interpretation of notes is application-specific. See Section <a href="#record-note">Note</a> for a discussion of the difference between note attributes and other records attributes.
+We also note the present tense in this term to indicate that it may not denote something in the past.</p>
+
+<div class="anexample">
+<p>
+The following records</p>
+<pre class="codexample">
+entity(e1,[prov:type="document"])
+entity(e2,[prov:type="document"])
+activity(a,t1,t2)
+used(u1,a,e1,[ex:file="stdin"])
+wasGeneratedBy(e2, a, [ex:file="stdout"])
+
+note(n1,[ex:icon="doc.png"])
+hasAnnotation(e1,n1)
+hasAnnotation(e2,n1)
+
+note(n2,[ex:style="dotted"])
+hasAnnotation(u1,n2)
+</pre>
+<p>assert the existence of two documents in the world (attribute-value pair: <span class="name">prov:type="document"</span>) identified by <span class="name">e1</span> and <span
+class="name">e2</span>, and annotate these records with a note indicating that the icon (an application specific way of rendering provenance) is <span class="name">doc.png</span>. It also
+asserts an activity, its usage of the first entity, and its generation of the second entity. The <span class="name">usage</span> record is annotated with a style (an application specific way
+of rendering this edge graphically). To be able to express this annotation, the usage record was provided with an identifier <span class="name">u1</span>, which was then referred to in <span
+class="name">hasAnnotation(u1,n2)</span>.
+</p>
+</div>
+
+
+</section>
+</section>
+
+<section id="bundle">
+<h3>Bundle</h3>
+
+<p>In this section, two constructs are introduced to group
+PROV-DM records. The first
+one, <a>account record</a> is itself a
+record, whereas the second
+one <a>record container</a> is not.
+</p>
+
+
+<section id="record-Account">
+<h3>Account Record</h3>
+
+<p>It is common for multiple provenance records to co-exist. For instance, when emailing
+ a file, there could be a provenance record kept by the mail client,
+ and another by the mail server. Such provenance records may provide different explanations about something happening in the world, because they are created by different parties or observed
+by different witnesses. A given party could also create multiple provenance records about an execution, to capture different levels of details, targeted at different end-users: the
+programmer of an experiment may be interested in a detailed log of execution, while the scientists may focus more on the scientific-level description. Given that multiple provenance
+records can co-exist, it is important to know who asserted these records. </p>
+
+<p>In PROV-DM, an <dfn id="dfn-Account">account record</dfn> is a wrapper of records with the following purposes: </p>
+<ul>
+<li> It is the mechanism by which attribution of provenance can be assserted; it allows asserters to bundle up their assertions, and assert suitable attribution;</li>
+<li> It provides a scoping mechanism for the uniqueness of identifiers (of elements and relations of PROV-DM);</li>
+<li> It provides a scoping mechanism for structural contraints (such as
+ <a href="#generation-uniqueness">generation-uniqueness</a> and <a href="#derivation-use">derivation-use</a> discussed in Section <a
+href="#structural-constraints">structural-constraints</a>).</li>
+</ul>
+
+
+
+<p>An account record, written <span class="name">account(id, assertIRI, recs, attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>id</em>: an identifier <span class="name">id</span> that identifies this account globally;</li>
+<li><em>asserter</em>: an IRI, denoted by <span class="name">assertIRI</span>, to identify an asserter; such IRI has no specific interpretation in the context of PROV-DM;</li>
+<li><em>records</em>: a set <span class="name">recs</span> of provenance records;</li>
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+<p>In PROV-ASN, an account record's text matches the <span class="nonterminal">accountRecord</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">accountRecord</span> ::=
+<span class="name">account</span>
+<span class="name">(</span>
+<span class="nonterminal">identifier</span>
+<span class="name">,</span>
+<span class="nonterminal">asserter</span>
+<span class="name">,</span>
+<span class="plus">
+<span class="nonterminal">record</span> </span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<div class='issue'>
+Currently, the non-terminal <span class="nonterminal">asserter</span> is defined as IRI and its interpretation is outside PROV-DM. We may want the asserter to be an agent instead, and
+therefore use PROV-DM to express the provenance of PROV-DM assertions. The editors seek inputs on how to resolve this issue.
+We seek inputs on how to resolve this issue. This is <a href="http://www.w3.org/2011/prov/track/issues/217">ISSUE-217</a>. </div>
+
+<div class="anexample" id="account-example-1">
+<p>
+The following account record</p>
+<pre class="codeexample">
+account(ex:acc0,
+ http://example.org/asserter,
+ entity(e0, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice" ])
+ ...
+ wasDerivedFrom(e2,e1)
+ ...
+ activity(a0,t,,[prov:type="createFile"])
+ ...
+ wasGeneratedBy(e0,a0)
+ ...
+ wasAssociatedWith(a4, ag5, [prov:role="communicator"]) )
+</pre>
+<p>contains the set of provenance records of section <a href="#example-prov-asn-encoding">example-prov-asn-encoding</a>, is asserted by agent <span
+class="name">http://example.org/asserter</span>, and is identified by identifier <span class="name">ex:acc0</span>.
+</p>
+</div>
+
+<p> An identifier in a record within the scope of an account is intended to denote a single record. However, nothing prevents an asserter from asserting an account containing, for example,
+multiple entity records with a same identifier but different attribute-values. In that case, they should be understood as a single entity record with this identifier and the union of all
+attributes values, as formalized in <a href="#identifiable-record-in-account">identifiable-record-in-account</a>.</p>
+
+<div class='constraint' id='identifiable-record-in-account'>
+<p>Given an entity record identifier <span class="name">e</span>, two sets of attribute-values denoted by <span class="name">av1</span> and <span class="name">av2</span>,
+ two entity records <span class="name">entity(e,av1)</span> and <span class="name">entity(e,av2)</span> occurring in an account are equivalent to the entity record <span
+class="name">entity(e,av)</span> where <span class="name">av</span> is the set of attribute-value pairs formed by the union of <span class="name">av1</span> and <span
+class="name">av2</span>.</p>
+
+<p>This constraint similarly applies to all other types of records. As a result, the identifier that occurs in a record is unique and acts as a local identifier for that record in that
+account.</p>
+</div>
+
+
+<p>Whilst constraint <a href="#identifiable-record-in-account">identifiable-record-in-account</a> specifies how to understand multiple entity records with a same identifier within a given account, it does not guarantee that the entity record formed with the union of all attribute-value pairs satisfies the <a>attribute occurrence validity</a> property, as illustrated by the following example.</p>
+
+
+<div class="anexample">
+<p>
+In the following account record, we find two entity records with a same identifier <span class="name">e</span>.</p>
+<pre class="codeexample">
+account(ex:acc1,
+ http://example.org/id,
+ entity(e,[prov:type="person", ex:age=20])
+ entity(e,[prov:type="person", ex:weight=50, ex:age=30])
+ ...)
+</pre>
+
+<p>Application of <a href="#identifiable-record-in-account">identifiable-record-in-account</a> results in an entity record containing the attribute-value pairs <span class="name">age=20</span>, <span class="name">weight=50</span>, and <span class="name">age=30</span>. The namespace referred to by prefix <span class="name">ex</span> declares the number of occurrences that are permitted for each attribute. The resulting entity record may or may not satisfy the <a>attribute occurrence validity</a>, depending on this namespace. For instance, if the namespace referred to by <span class="name">ex</span> declares that <span class="name">age</span> must have at most one occurrence, then the resulting entity record does not satisfy the <a>attribute occurrence validity</a> property. This document does not specify how to handle such an entity record.
+</p></div>
+
+<p>Account records can be nested since an account record can occur among the records being wrapped by another account. </p>
+
+
+
+<!--
+<p>
+An account is said to be well-formed if
+it satisfies the constraints <a href="#generation-uniqueness">generation-uniqueness</a> and <a href="#derivation-use">derivation-use</a>.</p>
+
+<p> The union of two accounts is another account,
+containing the unions of their respective records, where
+ records with a same identifier should be understood according to constraint <a href="#identifiable-record-in-account">identifiable-record-in-account</a>. Well-formed
+accounts are not
+closed under union because the
+constraint <a href="#generation-uniqueness">generation-uniqueness</a> may no
+longer be satisfied in the resulting union. </p>
+
+<div class="anexample">
+<p>
+Indeed, let us consider another account record</p>
+<pre class="codeexample">
+account(ex:acc2,
+ http://example.org/asserter2,
+ entity(e0, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice" ])
+ ...
+ activity(a1,t1,,[prov:type="createFile"])
+ ...
+ wasGeneratedBy(e0,a1,[ex:fct="create"])
+ ... )
+</pre>
+<p>with identifier <span class="name">ex:acc2</span>, containing assertions by asserter by <span class="name">http://example.org/asserter2</span> stating that the entity represented by
+entity record identified by <span class="name">e0</span> was generated by an activity represented by activity record identified by <span class="name">a1</span> instead of <span
+class="name">a0</span> in the previous account <span class="name">ex:acc0</span>. If accounts <span class="name">ex:acc0</span> and <span class="name">ex:acc2</span> are merged together,
+the resulting set of records violates <a href="#generation-uniqueness">generation-uniqueness</a> if the two activities <span class="name">a0</span> and <span class="name">a1</span> are
+distinct.</p>
+</div>
+
+-->
+
+<p>Account records constitute a scope for identifier uniqueness. Since accounts can be nested, scopes can also be nested; thus, the requirement on uniqueness of identifiers should be
+understood in the context of such nested scopes. When a record with an identifier occurs directly within an account, then its identifier denotes this record in the scope of this account,
+except in sub-accounts where records with the same identifier occur. </p>
+
+<div class="anexample">
+<p>
+The following account record is inspired from section <a href="#example-prov-asn-encoding">example-prov-asn-encoding</a>. This account, identified by <span class="name">ex:acc3</span>,
+declares entity record with identifier <span class="name">e0</span>, which is being referred to in the nested account <span class="name">ex:acc4</span>. Identifier <span
+class="name">e0</span> is uniquely identify a record in account <span class="name">ex:acc3</span>, including subaccount <span class="name">ex:acc4</span>.</p>
+<pre class="codeexample">
+account(ex:acc3,
+ http://example.org/asserter1,
+ entity(e0, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice" ])
+ activity(a0,t,,[prov:type="createFile"])
+ wasGeneratedBy(e0,a0,[])
+ account(ex:acc4,
+ http://example.org/asserter2,
+ entity(e1, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice", ex:content="" ])
+ activity(a0,t,,[prov:type="copyFile"])
+ wasGeneratedBy(e1,a0,[ex:fct="create"])
+ specializationOf(e1,e0)))
+</pre>
+<p>Alternatively, an activity record identified by <span class="name">a0</span> occurs in each of the two accounts. Therefore, each activity record is asserted in a separate scope, and
+therefore may represent different activities in the world.
+</p>
+</div>
+
+<p>The identifier of an account record is expected to be globally unique, whereas identifiers for other records are expected to be unique within the scope of the account in which their
+record occurs. </p>
+
+
+<p>The account record is the hook by which further meta information can be expressed about provenance, such as asserter, time of creation, signatures. The annotation mechanism can be used
+for this purpose, but how general meta-information is expressed is beyond the scope of this specification, except for asserters.</p>
+
+<div class="structural-forward">
+See Section <a href="#structural-constraints">structural-constraints</a> for a structural constraint on account records.
+</div>
+
+
+</section>
+
+<section id="RecordContainer">
+<h4>Record Container</h4>
+
+<p>A <dfn id="dfn-RecordContainer">record container</dfn> is a house-keeping construct of PROV-DM, also capable of bundling PROV-DM <a title="record">records</a>. A record container is the
+root of a provenance record and can be exploited to package up PROV-DM <a title="record">records</a> in response to a request for the provenance of something ([[!PROV-AQ]]). Given that a
+record container is the root of a provenance record, it is not defined as a PROV-DM record (production <span class="nonterminal">record</span>), since otherwise it could appear arbitrarily
+nested inside accounts.</p>
+
+
+<p>A record container, written <span class="name">container decls recs endContainer</span> in PROV-ASN, contains:
+<ul>
+<li><em>namespaceDeclarations</em>: a set <span class="name">decls</span> of namespace declarations, declaring namespaces and associated prefixes, which can be used in <a
+title="attribute">attributes</a> and <a title="identifier">identifiers</a> occurring inside <span class="name">recs</span>;</li>
+<li><em>records</em>: a non-empty set of records <span class="name">recs</span>.</li>
+</ul>
+<p>All the records in <span class="name">recs</span> are implictly wrapped in a default account, scoping all the record identifiers they declare directly, and constituting a toplevel
+account, in the hierarchy of accounts. Consequently, every provenance record is always expressed in the context of an account, either explicitly in an asserted account, or implicitly in a
+container's default account.</p>
+
+<p>In PROV-ASN, a record container's text matches the <span class="nonterminal">recordContainer</span> production of the grammar defined in this specification document.</p>
+
+
+<div class='grammar'>
+<span class="nonterminal">recordContainer</span> ::=
+<span class="name">container</span>
+<span class="nonterminal">namespaceDeclarations</span>
+<span class="plus"> <span class="nonterminal">record</span> </span>
+<span class="name">endContainer</span>
+</div>
+
+
+<div class="anexample">
+<p>
+The following container contains records related to the provenance of entity
+<span class="name">e2</span>.
+</p>
+<pre class="codeexample">
+container
+ prefix ex: http://example.org/,
+ entity(e2, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice",
+ ex:content="There was a lot of crime in London last month."])
+ activity(a1, 2011-11-16T16:05:00,,[prov:type="edit"])
+ wasGeneratedBy(e2, a1, [ex:fct="save"])
+ wasAssociatedWith(a1, ag2, [prov:role="author"])
+ agent(ag2, [ prov:type="prov:Person" %% xsd:QName, ex:name="Bob" ])
+endContainer
+</pre>
+<p>This container could for instance be returned by querying a provenance store for the provenance of entity <span class="name">e2</span> [[!PROV-AQ]]. All these assertions are implicitly
+wrapped in a default account. In the absence of an explicit account, such provenance records remain unattributed.
+</p>
+</div>
+
+<div class="anexample">
+<p>
+The following container </p>
+<pre class="codeexample">
+container
+ prefix ex: http://example.org/,
+
+ account(ex:acc1,http://example.org/asserter1,...)
+ account(ex:acc2,http://example.org/asserter1,...)
+endContainer
+</pre>
+<p> illustrates how two accounts with identifiers <span class="name">ex:acc1</span> and <span class="name">ex:acc2</span> can be returned in a PROV-ASN serialization of the provenance of
+something.
+</p>
+</div>
+
+
+<div class='issue'>
+Clarify what records are. This is <a href="http://www.w3.org/2011/prov/track/issues/208">ISSUE-208</a>. </div>
+</section>
+</section>
+
+
+<section id="sub-record">
+<h3>Further Terms in Records</h3>
+
+This section further terms in PROV-DM records.
+
+
+
+<section id="record-attribute">
+<h4>Attribute</h4>
+
+<p>An <dfn id="dfn-attribute">attribute</dfn> is a <em>qualified name</em>.
+An <dfn id="dfn-qualified-name">qualified name</dfn> is a name subject to namespace interpretation. It consists of namespace, denoted by an optional prefix, and a local name. The namespace
+is denoted by an IRI [[!IRI]].</p>
+
+
+<p>PROV-DM stipulates that a qualified name can be mapped into an IRI
+ by concatenating the IRI associated with the prefix and the local part (see detailed rule in [[!RDF-SPARQL-QUERY]], Section <a
+href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115/#QSynIRI">4.1.1</a>).</p>
+
+<p>A qualified name's prefix is OPTIONAL. If a prefix occurs in a
+ qualified name, it refers to a <a>namespace</a> declared in the
+ record container. In the absence of prefix, the qualified name
+ refers to the default namespace declared in the container.</p>
+
+<p>In PROV-ASN, an attribute's text matches the <span class="nonterminal">attribute</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">attribute</span> ::= <span class="nonterminal">qualifiedName</span><br/>
+<span class="nonterminal">qualifiedName</span> ::= <span class="nonterminal">prefixedName</span> | <span class="nonterminal">unprefixedName</span><br/>
+<span class="nonterminal">prefixedName</span> ::= <span class="nonterminal">prefix</span> <span class="name">:</span> <span class="nonterminal">localPart</span><br/>
+<span class="nonterminal">unprefixedName</span> ::= <span class="nonterminal">localPart</span><br/>
+<span class="nonterminal">prefix</span> ::= <em>a name without colon compatible with the <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName">NC_NAME</a> production
+[[!XML-NAMES]]</em><br/>
+<span class="nonterminal">localPart</span> ::= <em>a name without colon compatible with the <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName">NC_NAME</a> production
+[[!XML-NAMES]]</em>
+</div>
+
+
+<div class="note">Note that XML NC_NAME don't allow local identifiers to start with a number. Instead, should we use the productions used in SPARQL or TURTLE?</div>
+
+
+<p>
+For each attribute in a record, its namespace also declares the number of occurrences it
+may have in a list of attributes. The
+property <dfn>attribute occurrence validity</dfn> holds for a record
+if the actual number of occurrences of each attribute in this record is compatible with
+this attribute's declaration it its namespace. How to handle records
+that do not satisfy the <a>attribute occurrence validity</a> property
+is beyond the scope of this specification.</p>
+
+
+<p>From this specification's viewpoint, the interpretation of an attribute declared in a namespace other than prov-dm is out of
+scope.</p>
+
+<p>The PROV data model introduces a fixed set of attributes in the <a href="#prov-dm-namespace">PROV-DM namespace</a>:</p>
+<ul>
+<li> The attribute <dfn id="dfn-role"><span class="name">prov:role</span></dfn> denotes the function of an entity with respect to an activity, in the context of a usage, generation,
+activity association, start, end record. The attribute <span class="name">prov:role</span> is allowed to occur multiple times in such records. The value associated with a <span
+class="name">prov:role</span> attribute MUST be conformant with <span class="nonterminal">Literal</span>.
+<div class="anexample">
+<p>The following start record describes the role of the agent identified by <span class="name">ag</span> in this start relation with activity <span class="name">a</span>. </p>
+<pre class="codeexample">
+ wasStartedBy(a,ag, [prov:role="program-operator"])
+</pre>
+</div>
+ </li>
+
+<li> The attribute <dfn id="dfn-type"><span class="name">prov:type</span></dfn> provides further typing information for the element or relation asserted in the record. PROV-DM liberally
+defines a type as a category of things having common characteristics. PROV-DM is agnostic about the representation of types, and only states that
+the value associated with a <span class="name">prov:type</span> attribute MUST be conformant with <span class="nonterminal">Literal</span>. The attribute <span class="name">prov:type</span>
+is allowed to occur multiple times in a record.
+
+<div class="anexample">
+<p>The following record declares an agent of type software agent</p>
+<pre class="codeexample">
+ agent(ag, [prov:type="prov:SoftwareAgent" %% xsd:QName])
+</pre>
+</div>
+</li>
+
+<li> The attribute <dfn id="dfn-steps"><span class="name">prov:steps</span></dfn> defines the level of precision associated with a derivation record. The value associated with a <span
+class="name">prov:steps</span> attribute MUST be <span class="name">"single"</span> or <span class="name">"any"</span>. The attribute <span class="name">prov:step</span> occurs at most
+once in a derivation record. A derivation record without attribute <span class="name">prov:step</span> is considered to be equivalent to the same record extended with an extra attribute
+<span class="name">prov:step</span> and associated value <span class="name">"any"</span>.
+
+<div class="anexample">
+<p>The following record declares an imprecise-1 derivation, which is known to involve one activity, though its identity, usage details of <span class="name">ex:e1</span>, and generation
+details of <span class="name">ex:e2</span> are not asserted.</p>
+<pre class="codeexample">
+ wasDerivedFrom(ex:e2, ex:e1, [prov:steps="single"])
+</pre>
+</div>
+ </li>
+
+<li> The attribute <dfn id="dfn-label"><span class="name">prov:label</span></dfn> provides a human-readable representation of a PROV-DM element or relation.
+
+<div class='issue'>
+ This is <a href="http://www.w3.org/2011/prov/track/issues/219">ISSUE-219</a>. </div>
+</li>
+
+</ul>
+</section>
+
+
+
+<section id="record-identifier">
+<h4>Identifier</h4>
+
+
+<p>An <dfn id="dfn-identifier">identifier</dfn> is a <em>qualified name</em>. A qualified name can be mapped into an IRI
+ by concatenating the IRI associated with the prefix and the local part (see detailed rule in [[!RDF-SPARQL-QUERY]], Section <a
+href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115/#QSynIRI">4.1.1</a>).</p>
+
+<div class='grammar'>
+<span class="nonterminal">identifier</span> ::= <span class="nonterminal">qualifiedName</span><br/>
+<span class="nonterminal">eIdentifier</span> ::= <span class="nonterminal">identifier</span> <em>(intended to denote an entity record)</em><br/>
+<span class="nonterminal">aIdentifier</span> ::= <span class="nonterminal">identifier</span> <em>(intended to denote an activity record)</em><br/>
+<span class="nonterminal">agIdentifier</span> ::= <span class="nonterminal">identifier</span> <em>(intended to denote an agent record)</em><br/>
+<span class="nonterminal">gIdentifier</span>::= <span class="nonterminal">identifier</span> <em>(intended to denote a generation record)</em><br/>
+<span class="nonterminal">uIdentifier</span>::= <span class="nonterminal">identifier</span> <em>(intended to denote a usage record)</em><br/>
+<span class="nonterminal">nIdentifier</span>::= <span class="nonterminal">identifier</span> <em>(intended to denote a note record)</em><br/>
+<span class="nonterminal">accIdentifier</span>::= <span class="nonterminal">identifier</span> <em>(intended to denote an account record)</em>
+</div>
+
+
+</section>
+
+<section id="record-literal">
+<h4>Literal</h4>
+
+<p>
+A PROV-DM Literal represents a data value such as a particular string
+or number. A PROV-DM Literal represents a value whose interpretation is outside the scope of PROV-DM.
+</p>
+
+<p>In PROV-ASN, a Literal's text matches the <span class="nonterminal">Literal</span> production of the grammar defined in this specification document.</p>
+
+<div class='grammar'>
+<span class="nonterminal">Literal</span> ::= <span class="nonterminal">typedLiteral</span> | <span class="nonterminal">convenienceNotation</span> <br/>
+<span class="nonterminal">typedLiteral</span> ::= <span class="nonterminal">quotedString</span> <span class="name">%%</span> <span class="nonterminal">datatype</span><br/>
+<span class="nonterminal">datatype</span> ::= <span class="nonterminal">qualifiedName</span><br/>
+<span class="nonterminal">convenienceNotation</span> ::= <span class="nonterminal">stringLiteral</span> | <span class="nonterminal">intLiteral</span><br/>
+<span class="nonterminal">stringLiteral</span> ::= <span class="nonterminal">quotedString</span><br/>
+<span class="nonterminal">quotedString</span> ::= <em>a finite sequence of characters in which " (U+22) and \ (U+5C) occur only in pairs of the form \" (U+5C, U+22) and \\ (U+5C,
+U+5C), enclosed in a pair of " (U+22) characters</em><br/>
+<span class="nonterminal">intLiteral</span> ::= <em>a finite-length sequence of decimal digits (#x30-#x39) with an optional leading negative sign (-)</em>
+</div>
+
+<p>The non terminals <span class="nonterminal">stringLiteral</span> and
+<span class="nonterminal">intLiteral</span>
+are syntactic sugar for quoted strings with datatype <span class="name">xsd:string</span> and <span class="name">xsd:int</span>, respectively.
+</p>
+
+<p> In particular, a PROV-DM Literal may be an IRI-typed string (with datatype <span class="name">xsd:anyURI</span>); such IRI has no specific interpretation in the context of PROV-DM.</p>
+
+
+<div class="anexample">
+<p>
+The following examples respectively are the string "abc" (expressed using the convenience notation), the string "abc", the integer number 1, the integer number 1 (expressed using the
+convenience notation) and the IRI "http://example.org/foo".
+<pre class="codeexample">
+ "abc"
+ "abc" %% xsd:string
+ "1" %% xsd:int
+ 1
+ "http://example.org/foo" %% xsd:anyURI
+</pre>
+The following example shows a literal of type <span class="name">xsd:QName</span> (see
+<a href="http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/#QName">QName</a> [[!XMLSCHEMA-2]]).
+The prefix <span class="name">ex</span> MUST be bound to a <a>namespace</a> declared in the
+ record container.
+<pre class="codeexample">
+ "ex:value" %% xsd:QName
+</pre>
+</div>
+
+
+
+<div class='note'>Should we define structural equivalence of literals as in OWL2? [[!OWL2-SYNTAX]]
+(see section <a href="http://www.w3.org/TR/2009/REC-owl2-syntax-20091027/#Literals">Literals</a>).
+</div>
+
+</section>
+
+
+
+
+<section id="record-Time">
+<h4>Time</h4>
+
+<p><dfn id="dfn-time">Time instants</dfn> are defined according to xsd:dateTime [[!XMLSCHEMA-2]].</p>
+
+
+
+<p>It is OPTIONAL to assert time in usage, generation, and activity records.</p>
+
+
+
+
+</section>
+
+<section id="record-Asserter">
+<h3>Asserter</h3>
+
+<p>An <dfn id="dfn-asserter">asserter</dfn> is a creator of PROV-DM records. An asserter is denoted by an IRI. Such IRI has no specific interpretation in the context of PROV-DM.</p>
+
+<div class='grammar'>
+<span class="nonterminal">asserter</span> ::= <span class="nonterminal">IRI</span><br/>
+<span class="nonterminal">IRI</span> ::= <em>an IRI compatible with production IRI in [[!IRI]], enclosed in a pair of < (U+3C) and > (U+3E) characters </em>
+</div>
+
+<div class='issue'>
+Currently, the non-terminal <span class="nonterminal">asserter</span> is defined as IRI. We may want the asserter to be an agent instead, and therefore use PROV-DM to express the provenance
+of PROV-DM. We seek inputs on how to resolve this issue. This is <a href="http://www.w3.org/2011/prov/track/issues/217">ISSUE-217</a></div>
+
+</section>
+
+<section id="record-NamespaceDeclaration">
+<h3>Namespace Declaration</h3>
+
+<p>A PROV-DM <dfn id="dfn-namespace">namespace</dfn> is identified by an IRI reference [[!IRI]]. In PROV-DM, attributes, identifiers, and literals of with datatype <span
+class="name">xsd:QName</span> can be placed in a namespace using the mechanisms described in this specification. </p>
+
+
+<p>A <dfn id="dfn-namespaceDeclaration">namespace declaration</dfn> consists of a binding between a prefix and a namespace. Every qualified name with this prefix in the scope of this
+declaration refers to this namespace.
+A <dfn id="dfn-defaultNamespaceDeclaration">default namespace declaration</dfn> consists of a namespace. Every unprefixed qualified name in the scope of this default namespace declaration
+refers to this namespace.</p>
+
+<div class='grammar'>
+<span class="nonterminal">namespaceDeclarations</span> ::=
+ | <span class="group"><span class="nonterminal">defaultNamespaceDeclaration</span> | <span class="nonterminal">namespaceDeclaration</span></span> <span class="star"> <span
+class="nonterminal">namespaceDeclaration</span></span><br>
+<span class="nonterminal">namespaceDeclaration</span> ::=
+<span class="name">prefix</span> <span class="nonterminal">prefix</span> <span class="nonterminal">IRI</span><br/>
+<span class="nonterminal">defaultNamespaceDeclaration</span> ::=
+ <span class="name">default</span> <span class="nonterminal">IRI</span> <br/>
+</div>
+</section>
+
+
+
+
+
+
+<section id="record-Location">
+<h3>Location</h3>
+
+<p><dfn id="dfn-Location">Location</dfn> is an identifiable geographic place (ISO 19112). As such, there are numerous ways in which location can be expressed, such as by a coordinate,
+address, landmark, row, column, and so forth. This document does not specify how to concretely express locations, but instead provide a mechanism to introduce locations in assertions. </p>
+
+
+<p>
+Location is an OPTIONAL attribute of entity records and activity records. The value associated with a attribute <span class="name">location</span> MUST be a <span
+class="nonterminal">Literal</span>, expected to denote a location.
+</p>
+
+
+
+
+</section>
+
+</section>
+
+</section>
+
+
+ <section id="common-relations">
+<h2>PROV-DM Common Relations</h2>
+
+<p>This section contains the normative specification of common relations of PROV-DM.</p>
+
+
+
+
+<p>The following figure summarizes the additional relations described in subsections 6.1 to 6.7.</p>
+
+<div style="text-align: center;">
+<figure>
+<img src="sec6-summary.png" alt="common relations"/>
+<figcaption>PROV-DM Common Relations</figcaption>
+</figure>
+</div>
+
+<section id="record-traceability">
+<h3>Traceability Record</h3>
+
+<p> It is common that we may want to know who or what may have some influence, whether direct or indirect, on a given entity, or who may, directly or not, have some responsibility for a
+given outcome. Hence, we may want to infer such a notion from an existing set of PROV-DM records. Vice-versa, we may have knowledge of this influence and responsibility, but without
+knowing its actual details. Thus, we may also want to assert such a notion. </p>
+
+<p> A <dfn id="dfn-Traceability">traceability record</dfn> states the existence of a "dependency path" between two entities, indicating that one entity can be shown to be in the lineage of
+another, and may have influenced it, or may bear some responsibility for it, in some way. The traceability relation subsumes derivation, activity association, and responsibility, and is
+defined to be transitive. </p>
+
+<p> A traceability record, written <span class="name">tracedTo(id,e2,e1,attrs)</span> in PROV-ASN, contains the following components:</p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the traceability record;</li>
+<li><em>entity</em>: an identifier <span class="name">e2</span> identifying an entity;
+<li><em>ancestor</em>: an identifier <span class="name">e1</span> identifying an ancestor entity in the lineage of <span class="name">e2</span>;
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+<p>In PROV-ASN, a traceability record's text matches the <span class="nonterminal">traceabilityRecord</span> production of the grammar defined in this specification document.</p>
+
+
+<div class='grammar'>
+<span class="nonterminal">traceabilityRecord</span> ::=
+<span class="name">tracedTo</span>
+<span class="name">(</span>
+<span class="optional"><span class="nonterminal">identifier</span>
+<span class="name">,</span></span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<p>A traceability record can be inferred from existing records, or can be asserted stating that such a dependency path exists without the asserter knowing its individual steps, as expressed
+by the following inference and constraint, respectively.
+
+<div class='inference' id='traceability-inference'>
+Given two identifiers <span class="name">e2</span> and <span class="name">e1</span> identifying entity records,
+the following statements hold:
+
+<ol>
+<li><span class='conditional'>If</span> <span class="name">wasDerivedFrom(e2,e1,a,g2,u1)</span> holds, for some <span class="name">a</span>, <span class="name">g2</span>, <span
+class="name">u1</span>, <span class='conditional'>then</span> <span class="name">tracedTo(e2,e1)</span> also holds.</li>
+<li><span class='conditional'>If</span> <span class="name">wasDerivedFrom(e2,e1)</span> holds, <span class='conditional'>then</span> <span class="name">tracedTo(e2,e1)</span> also
+holds.</li>
+<li><span class='conditional'>If</span> <span class="name">wasGeneratedBy(e2,a,gAttr) and wasAssociatedWith(a,e1)</span> hold, for some <span class="name">a</span> and <span
+class="name">gAttr</span>, <span class='conditional'>then</span> <span class="name">tracedTo(e2,e1)</span> also holds.</li>
+<li><span class='conditional'>If</span> <span class="name">wasGeneratedBy(e2,a,gAttr)</span>, <span class="name">wasAssociatedWith(a,e)</span> and <span
+class="name">actedOnBehalfOf(e,e1)</span> hold, for some <span class="name">a</span>, <span class="name">e</span>, and <span class="name">gAttr</span>, <span
+class='conditional'>then</span> <span class="name">tracedTo(e2,e1)</span> also holds.</li>
+<li><span class='conditional'>If</span> <span class="name">wasGeneratedBy(e2,a,gAttr) and wasStartedBy(a,e1,sAttr)</span> hold, for some <span class="name">a</span>, <span
+class="name">e</span>, and <span class="name">gAttr</span>, and <span class="name">sAttr</span>, <span class='conditional'>then</span> <span class="name">tracedTo(e2,e1)</span> also
+holds.</li>
+<li><span class='conditional'>If</span> <span class="name">tracedTo(e2,e)</span> and <span class="name">tracedTo(e,e1)</span> hold for some <span class="name">e</span>, <span
+class='conditional'>then</span> <span class="name">tracedTo(e2,e1)</span> also holds.</li>
+</ol>
+</div>
+
+<p>We note that the inference rule <a href="#traceability-inference">traceability-inference</a> does not allow us to infer attributes, which are record and application specific. </p>
+
+<div class='constraint' id='traceability-assertion'>
+<span class='conditional'>If</span> the record <span class="name">tracedTo(r2,r1,attrs)</span> holds for two identifiers <span class="name">r2</span> and <span class="name">r1</span>
+identifying entity records, and attribute-value pairs <span class="name">attrs</span>,
+ <span class='conditional'>then</span> there exist
+<span class="name">e<sup>0</sup></span>, <span class="name">e<sup>1</sup></span>, ..., <span class="name">e<sup>n</sup></span> for <span class="name">n≥1</span>, with <span
+class="name">e<sup>0</sup></span>=<span class="name">r2</span> and <span class="name">e<sup>n</sup></span>=<span class="name">r1</span>, and
+for any i such that <span class="name">0≤i≤n-1</span>, at least of the following statements holds:
+<ul>
+<li> <span class="name">wasDerivedFrom(e<sup>i</sup>,e<sup>i+1</sup>,a,g2,u1)</span> holds, for some <span class="name">a</span>, <span class="name">g2</span>, <span class="name">u1</span>,
+or</li>
+<li> <span class="name">wasDerivedFrom(e<sup>i</sup>,e<sup>i+1</sup>)</span> holds, or</li>
+<li> <span class="name">wasBasedOn(e<sup>i</sup>,e<sup>i+1</sup>)</span> holds, or</li>
+<li> <span class="name">wasGeneratedBy(e<sup>i</sup>,a,gAttr) and wasAssociatedWith(a,e<sup>i+1</sup>)</span> hold, for some <span class="name">a</span> and <span
+class="name">gAttr</span>, or</li>
+<li> <span class="name">wasGeneratedBy(e<sup>i</sup>,a,gAttr)</span>, <span class="name">wasAssociatedWith(a,e)</span> and <span class="name">actedOnBehalfOf(e,e<sup>i+1</sup>)</span> hold,
+for some <span class="name">a</span>, <span class="name">e</span> and <span class="name">gAttr</span>, or</li>
+<li> <span class="name">wasGeneratedBy(e<sup>i</sup>,a,gAttr) and wasStartedBy(a,e<sup>i+1</sup>,sAttr)</span> hold, for some <span class="name">a</span>, <span class="name">e</span>, and
+<span class="name">gAttr</span>, and <span class="name">sAttr</span>.</li>
+</ul>
+</div>
+
+<p>We note that the previous constraint is not really an inference <em>rule</em>, since there is nothing that we can actually infer. Instead, this constraint should simply be seen as part
+of the definition of the traceability record. </p>
+
+
+</section>
+
+<section id="record-OrderingOfActivities">
+<h3>Activity Ordering Record</h3>
+
+
+
+<p>PROV-DM allows dependencies amongst activities to be expressed.
+An <dfn id="InformationFlowOrdering">information flow ordering record</dfn> is a representation that an entity was generated by an activity, before it was used by another activity.
+A <dfn id="ControlOrdering">control ordering record</dfn> is a representation that an activity was initiated by another activity.
+</p>
+
+<p>In PROV-ASN, an activity ordering record's text matches the <span class="nonterminal">activityOrderingRecord</span> production of the grammar defined in this specification document.
+</p>
+
+<div class='grammar'>
+<span class="nonterminal">activityOrderingRecord</span> ::=
+<span class="nonterminal">informationFlowOrderingRecord</span> |
+<span class="nonterminal">controlOrderingRecord</span>
+<br/>
+
+<span class="nonterminal">informationFlowOrderingRecord</span> ::=
+<span class="name">wasInformedBy</span>
+<span class="name">(</span>
+<span class="optional"><span class="nonterminal">identifier</span>
+<span class="name">,</span>
+</span>
+<span class="nonterminal">aIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">aIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+<br/>
+
+<span class="nonterminal">controlOrderingRecord</span> ::=
+<span class="name">wasStartedBy</span>
+<span class="name">(</span>
+<span class="optional"><span class="nonterminal">identifier</span>
+<span class="name">,</span>
+</span>
+<span class="nonterminal">aIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">aIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+<br/>
+</div>
+
+
+<p>
+An information flow ordering record, written as
+<span class="name">wasInformedBy(id,a2,a1,attrs)</span> in PROV-ASN, contains:
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span> identifying the record;</li>
+<li><em>informed</em>: the identifier <span class="name">a2</span> of an activity record representing the informed activity;
+<li><em>informant</em>: the identifier <span class="name">a1</span> of an activity record representing the informant activity;
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+<p> An information flow ordering record is formally defined as follows.</p>
+
+<div class='constraint' id='wasInformedBy-Definition'>Given two activity records identified by <span class="name">a1</span> and <span class="name">a2</span>,
+ the record <span class="name">wasInformedBy(a2,a1)</span>
+holds, <span class='conditional'>if and only if</span>
+ there is an entity record identified by <span class="name">e</span> and sets of attribute-value pairs <span class="name">attrs1</span> and <span class="name">attrs2</span>,
+such that <span class="name">wasGeneratedBy(e,a1,attrs1)</span> and <span class="name">used(a2,e,attrs2)</span> hold.
+</div>
+
+
+<div class="interpretation-forward">
+For the interpretation of an information flow ordering record, see <a href="#wasInformedBy-ordering">wasInformedBy-ordering</a>.
+</div>
+
+<!--
+<div class='interpretation' id='wasInformedBy-ordering'>
+Given two activity records denoted by <span class="name">a1</span> and <span class="name">a2</span>, <span class='conditional'>if</span> the record <span
+class="name">wasInformedBy(a2,a1)</span>
+ holds, <span class='conditional'>then</span> the following temporal constraint holds:
+the <a title="activity start event">start event</a> of the activity record denoted by <span class="name">a1</span> <a>precedes</a> the <a title="activity end event">end event</a> of
+the activity record denoted by <span class="name">a2</span>.
+</div>
+-->
+
+<p>The relationship <span class="name">wasInformedBy</span> is not transitive. Indeed, consider the following records.</p>
+<pre class="codeexample">
+wasInformedBy(a2,a1)
+wasInformedBy(a3,a2)
+</pre>
+<p> We cannot infer <span class="name">wasInformedBy(a3,a1)</span> from them. Indeed,
+from
+<span class="name">wasInformedBy(a2,a1)</span>, we know that there exists <span class="name">e1</span> such that <span class="name">e1</span> was generated by <span class="name">a1</span>
+and used by <span class="name">a2</span>. Likewise, from <span class="name">wasInformedBy(a3,a2)</span>, we know that there exists <span class="name">e2</span> such that <span
+class="name">e2</span> was generated by <span class="name">a2</span> and used by <span class="name">a3</span>. The following illustration shows a case for which transitivity cannot hold. The
+horizontal axis represents the event line. We see that <span class="name">e1</span> was generated after <span class="name">e2</span> was used. Furthermore, the illustration also shows that
+<span class="name">a3</span> completes before <span class="name">a1</span>. So it is impossible for <span class="name">a3</span> to have used an entity generated by <span
+class="name">a1</span>.</p>
+
+<div style="text-align: center;">
+<figure>
+<img src="informedByNonTransitive.png" alt="non transitivity of wasInformedBy" />
+<figcaption>Counter-example for transitivity of wasInformedBy</figcaption>
+</figure>
+</div>
+
+<p>
+A control ordering record, written as
+<span class="name">wasStartedBy(a2,a1, attrs)</span> in PROV-ASN, contains: </p>
+<ul>
+<li><em>id</em>: an OPTIONAL identifier <span class="name">id</span>;</li>
+<li><em>started</em>: refers to an activity record identified by <span class="name">a2</span>, representing the started activity;
+<li><em>starter</em>: refers to an activity record identified by <span class="name">a1</span>, representing the activity that started <span class="name">a1</span>;</li>
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+<p>Such a record states control ordering between <span class="name">a2</span> and <span class="name">a1</span>, specified as follows.</p>
+
+<div class='constraint' id='wasStartedBy'>Given two activity records identified by <span class="name">a1</span> and <span class="name">a2</span>,
+ the record <span class="name">wasStartedBy(a2,a1)</span>
+holds <span class='conditional'>if and only if</span>
+ there exist an entity record identified by <span class="name">e</span>
+and some attributes <span class="name">gAttr</span> and <span class="name">sAttr</span>,
+such that
+ <span class="name">wasGeneratedBy(e,a1,gAttr)</span>
+ and <span class="name">wasStartedBy(a2,e,sAttr)</span> hold.
+</div>
+
+<p>We note that a <a>start record</a> associates an activity with an agent, and is denoted by the name <span class="name">wasStartedBy</span>. A <a>control ordering record</a> associates an
+activity with another activity, also denoted by the name <span class="name">wasStartedBy</span>. Effectively, by considering both record types, the relation <span
+class="name">wasStartedBy</span> has a range formed by the union of agents and activities.</p>
+
+
+<div class="anexample">
+<p>
+In the following assertions, we find two activity records, identified by <span class="name">a1</span> and <span class="name">a2</span>, representing two activities, which took place on two
+separate hosts. The third record indicates that the latter activity was started by the former.</p>
+<pre class="codeexample">
+activity(a1,t1,t2,[ex:host="server1.example.org",prov:type="workflow"])
+activity(a2,t3,t4,[ex:host="server2.example.org",prov:type="subworkflow"])
+wasStartedBy(a2,a1)
+</pre>
+
+<p>Alternatively, we could have asserted the existence of an entity, representing a request to create a sub-workflow. This request, issued by <span class="name">a1</span>, triggered the
+start of <span class="name">a2</span>.
+</p>
+<pre class="codeexample">
+entity(e,[prov:type="creation-request"])
+wasGeneratedBy(e,a1)
+wasStartedBy(a2,e)
+</pre>
+</div>
+
+
+<div class="interpretation-forward">
+For the interpretation of a control flow ordering record, see <a href="#wasStartedBy-ordering">wasStartedBy-ordering</a>.
+</div>
+
+
+</section>
+
+<section id="record-Revision">
+<h3>Revision Record</h3>
+
+<p> A <dfn id="dfn-Revision">revision record</dfn> is a representation of the creation of an entity considered to be a variant of another. Deciding whether something is made available as a
+revision of something else usually involves an agent who represents someone in the world who takes responsibility for approving that the former is a due variant of the latter. </p>
+
+<p> A revision record, written <span class="name">wasRevisionOf(e2,e1,ag,attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>newer</em>: an identifier <span class="name">e2</span> identifying an entity that represents a newer version of an entity;
+<li><em>older</em>: an identifier <span class="name">e1</span> identifying an entity that represents an older version of an entity;
+<li><em>responsibility</em>: an OPTIONAL identifier <span class="name">ag</span> for the agent who approved that <span class="name">e2</span> is a variant of <span class="name">e1</span>;
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+
+<p>In PROV-ASN, a revision record's text matches the <span class="nonterminal">revisionRecord</span> production of the grammar defined in this specification document.
+</p>
+
+<div class='grammar'>
+<span class="nonterminal">revisionRecord</span> ::=
+<span class="name">wasRevisionOf</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="optional"><span class="name">,</span>
+<span class="nonterminal">agIdentifier</span></span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+
+
+
+
+<p>A revision record needs to satisfy the following constraint, linking the two entity records by a derivation, and stating them to be a complement of a third entity record.</p>
+
+<div class='inference' id='wasRevision'>
+Given two identifiers <span class="name">old</span> and <span class="name">new</span> identifying two entities, and an identifier <span class="name">ag</span> identifying an agent,
+<span class='conditional'>if</span> a record <span class="name">wasRevisionOf(new,old,ag)</span> is asserted, <span class='conditional'>then</span>
+there exists an entity record identifier <span class="name">e</span> and attribute-values <span class="name">eAttrs</span>, <span class="name">dAttrs</span>, such that the following records
+hold:
+<ul>
+<li> <span class="name">wasDerivedFrom(new,old,dAttrs)</span>;
+<li> <span class="name">entity(e,eAttrs)</span>;
+<li> <span class="name">specializationOf(new,e)</span>;
+<li> <span class="name">specializationOf(old,e)</span>.
+</ul>
+The derivation record may be imprecise-1 or imprecise-n.
+</div>
+
+<p><span class="name">wasRevisionOf</span> is a strict sub-relation
+ of <span class="name">wasDerivedFrom</span> since two entities <span class="name">e2</span> and <span class="name">e1</span>
+ may satisfy <span class="name">wasDerivedFrom(e2,e1)</span> without being a variant of
+ each other.
+</p>
+
+<div class="anexample">
+<p>
+The following revision assertion</p>
+<pre class="codeexample">
+agent(ag,[prov:type="QualityController"])
+entity(e1,[prov:type="document"])
+entity(e2,[prov:type="document"])
+wasRevisionOf(e2,e1,ag)
+</pre>
+<p>states that the document represented by entity record identified by <span class="name">e2</span> is a revision of document represented by entity record identified by <span
+class="name">e1</span>; agent denoted by <span class="name">ag</span> is responsible for this new versioning of the document.
+</p>
+</div>
+
+
+
+</section>
+
+
+<section id="recod-attribution">
+<h3>Attribution Record</h3>
+
+<p>An <dfn>attribution record</dfn> represents that an entity is ascribed to an agent.</p>
+
+
+<p> An attribution record, written <span class="name"> wasAttributedTo(e,ag,attr)</span> in PROV-ASN, contains the following components:</p>
+<ul>
+<li><em>entity</em>: an identifier <span class="name">e</span> of an entity record;</li>
+<li><em>agent</em>: an identifier <span class="name">ag</span> of an agent whom the entity is attributed to;</li>
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+<p>Attribution models the notion of an activity generating an entity identified by <span class="name">e</span> being associated with an agent <span class="name">ag</span>, which takes
+responsibility for generating <span class="name">e</span>. Formally, this is expressed as the following necessary condition.</p>
+
+
+<div class='inference' id='attribution-implication'>
+<span class='conditional'>If</span>
+<span class="name">wasAttributedTo(e,ag)</span> holds for some identifiers
+<span class="name">e</span> and <span class="name">ag</span>,
+<span class='conditional'>then</span> there exists an activity identified by <span class="name">a</span> such that the following statements hold:
+<pre>
+activity(a,t1,t2,attr1)
+wasGenerateBy(e,a)
+wasAssociatedWith(a,ag,attr2)
+</pre>
+for some sets of attribute-value pairs <span class="name">attr1</span> and <span class="name">attr2</span>, time <span class="name">t1</span>, and <span class="name">t2</span>.
+</div>
+
+<p>In PROV-ASN, an attribution record's text matches the <span class="nonterminal">attributionRecord</span> production of the grammar.</p>
+
+<div class='grammar'>
+<span class="nonterminal">attributionRecord</span> ::=
+<span class="name">wasAttributedTo</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">agIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+</section>
+
+
+<section id="record-quotation">
+<h3>Quotation Record</h3>
+
+
+<p> A <dfn>quotation record</dfn> is a representation of the repeating or copying of some part of an entity.</p>
+
+
+<p> A quotation record, written <span class="name"> wasQuotedFrom(e2,e1,ag2,ag1,attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>quote</em>: an identifier <span class="name">e2</span>, identifying an entity record that represents the quote;
+<li><em>quoted</em>: an identifier <span class="name">e1</span>, identifying an entity record representing what is being quoted;
+<li><em>quoterAgent</em>: an OPTIONAL identifier <span class="name">ag2</span> of the agent who is doing the quoting;
+<li><em>quotedAgent</em>: an OPTIONAL identifier <span class="name">ag1</span> of the agent that is quoted;
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+
+</ul>
+
+<p>In PROV-ASN, a quotation record's text matches the <span class="nonterminal">quotationRecord</span> production of the grammar.</p>
+
+<div class='grammar'>
+<span class="nonterminal">quotationRecord</span> ::=
+<span class="name">wasQuotedFrom</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">agIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">agIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+
+
+<div class='inference' id='quotation-implication'>
+<span class='conditional'>If</span>
+<span class="name">wasQuotedFrom(e2,e1,ag2,ag1,attrs)</span> holds for some identifiers
+<span class="name">e2</span>, <span class="name">e1</span>, <span class="name">ag2</span>, <span class="name">ag1</span>,
+<span class='conditional'>then</span> the following records hold:
+<pre>
+wasDerivedFrom(e2,e1)
+wasAttributedTo(e2,ag2)
+wasAttributedTo(e1,ag1)
+</pre>
+</div>
+
+</section>
+
+
+<section id="record-summary">
+<h3>Summary Record</h3>
+<p>A <dfn>summary record</dfn> represents that an entity (expected to be a document) is a synopsis or abbreviation of another entity (also expected to be a document). </p>
+
+
+
+<p> A summary record, written <span class="name"> wasSummaryOf(e2,e1,attrs)</span> in PROV-ASN, contains:</p>
+<ul>
+<li><em>summarizedEntity</em>: an identifier <span class="name">e2</span> for the entity record that represents the summary;
+<li><em>fullEntity</em>: an identifier <span class="name">e1</span> for the entity record that represents what is being summarized;
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+<p>
+<span class="name">wasSummaryOf</span> is a strict sub-relation of <span class="name">wasDerivedFrom</span>.
+</p>
+
+
+<p>In PROV-ASN, a summary record's text matches the <span class="nonterminal">summaryRecord</span> production of the grammar.</p>
+
+<div class='grammar'>
+<span class="nonterminal">summaryRecord</span> ::=
+<span class="name">wasSummaryOf</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+<div class='issue'>Drop this relation <a href="http://www.w3.org/2011/prov/track/issues/220">ISSUE-220</a>.</div>
+
+
+
+</section>
+
+<section id="record-orignal-source">
+<h3>Original Source Record</h3>
+
+<p>An <dfn>original source record</dfn> represents an entity in
+which another entity first appeared. </p>
+
+
+<p> An assertion hadOriginalSource, written <span class="name"> hadOriginalSource(e2,e1,attrs)</span>, contains:</p>
+<ul>
+<li><em>entity</em>: an identifier <span class="name">e1</span> for the entity record representing the original entity; </li>
+<li><em>source</em>: an identifier <span class="name">e2</span> for an entity record, representing an entity that had appeared previously;</li>
+<li><em>attributes</em>: an OPTIONAL set <span class="name">attrs</span> of attribute-value pairs to further describe this record.</li>
+</ul>
+
+<p>
+ <span class="name">hasOriginalSource</span> is a strict sub-relation of <span class="name">wasDerivedFrom</span>.
+</p>
+
+<p>In PROV-ASN, an original source record's text matches the <span class="nonterminal">originalSourceRecord</span> production of the grammar.</p>
+
+<div class='grammar'>
+<span class="nonterminal">originalSourceRecord</span> ::=
+<span class="name">hadOriginalSource</span>
+<span class="name">(</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+<span class="nonterminal">eIdentifier</span>
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span>
+</div>
+
+</section>
+
+
+
+<section id="record-Collection">
+<h3>Collections</h3>
+
+<div class='issue'>
+Section in flux to address
+various comments about collections:
+<a href="http://www.w3.org/2011/prov/track/issues/135">ISSUE-135</a>,
+<a href="http://www.w3.org/2011/prov/track/issues/135">ISSUE-136</a>,
+<a href="http://www.w3.org/2011/prov/track/issues/135">ISSUE-137</a>,
+<a href="http://www.w3.org/2011/prov/track/issues/135">ISSUE-138</a>
+<a href="http://www.w3.org/2011/prov/track/issues/135">ISSUE-139</a>
+</div>
+
+The intent of the <em>collection</em> record types relations introduced in this section is to account for <strong>part-of</strong> relationships that may exist amongst entities. Specifically, this section:
+
+<ul>
+ <li>introduces a new built-in type <span class="name">collection</span>, and </li>
+ <li>introduces relations that let asserters describe how the content of entities of type collection changes over time, as a consequence of insertion and deletion operations.</li>
+ </ul>
+
+<p>We adopt a very generic form of collection for the purpose, namely an abstract data types consisting of <strong>set of key-value pairs</strong>, often referred to as a <strong>map</strong>. This provides a generic indexing structure that can be used to model commonly used data structures, including associative lists (also known as "dictionaries" or maps in some programming languages), relational tables, ordered lists, and more (the specification of such specialized structures in terms of key-value pairs is out of the scope of this document).</p>
+
+<p>Keys and values used in collections are literals. This allows expressing nested collections, that is, collections whose values include entities of type collection.</p>
+
+<p>The following relations and corresponding record types are introduced to model (a) insertion of a new key-value pair into a collection and (b) removal of a key-value pair from a collection.</p>
+
+<ul>
+ <li>Record: <span class="name">CollectionAfterInsertion(c2,c1, k, v)</span> denotes that collection <span class="name">c2</span> represents the new state of collection <span class="name">c1</span>,
+following the insertion of pair <span class="name">(k,v)</span> into <span class="name">c1</span></li>
+
+<li> Record: <span class="name">CollectionAfterRemoval(c2,c1, k)</span> denotes that collection <span class="name">c2</span> represents the removal of pair <span class="name">(k,v)</span> from <span class="name">c1</span>, where <span class="name">v</span> is the value
+corresponding to key <span class="name">k</span> in <span class="name">c1</span>. </li>
+
+</ul>
+
+<p>
+Because these relations state the derivation of a collection from another, formally they are specializations of the precise-1 <a
+href="#Derivation-Relation"><strong>wasDerivedFrom</strong></a> relation.</p>
+
+The following entity types are introduced:
+
+<ul>
+ <li> <span class="name">prov:type="Collection"%%xsd:QName</span> denotes that the entity is a collection, that is, it can participate in <span class="name">CollectionAfterInsertion</span> and <span class="name">CollectionAfterDeletion</span> relations;
+
+ <li><span class="name">prov:type="emptyCollection"%%xsd:QName</span> denotes that the entity is a collection, and furthermore that it does not contain any key-value pairs.
+</ul>
+
+<div class="note">Given the specific nature of the derivation, the intervening activity that accounts for imprecise-1 derivation should have an equally specific type, such as"
+collection-insertion" and "collection-rmoval". This is left for a future version.</div>
+
+<p>The intent of these relations and entity types is to capture the <em>history of changes that occurred to a collection</em>. </p>
+
+<p>The following examples illustrate how these assertions are expected to be used in practice.</p>
+
+<div class="anexample">
+<pre class="codeexample">
+ entity(c, [prov:type="EmptyCollection"]) // e is an empty collection
+ entity(k1)
+ entity(v1)
+ entity(k2)
+ entity(v2)
+ entity(c1, [prov:type="Collection"])
+ entity(c2, [prov:type="Collection"])
+
+ CollectionAfterInsertion(c1, c, k1, v1) // c1 = { (k1,v1) }
+ CollectionAfterInsertion(c2, c1, k2, v2) // c2 = { (k1,v1), (k2 v2) }
+ CollectionAfterRemoval(c3, c2, k1) // c3 = { (k2,v2) }
+</pre>
+</div>
+
+<p>This representation of a collection's evolution makes no assumption regarding the underlying data structure used to store and manage collections. In particular, no assumptions are needed regarding the mutability of a data structure that is subject to updates. In fact, the state of a collection (i.e., the set of key-value pairs it contains) at a given point in a sequence of operations is never stated explicitly. Rather, it can be obtained by querying the chain of derivation assertions involving insertions and removals. Entity type <span class="name">prov:type="emptyCollection"</span> can be used in this context as it marks the start of a sequence of collection operations.</p>
+
+<p>Observations:</p>
+<ul>
+
+ <li> One can have multiple assertions regarding the state of a collection following a <em>set</em> of insertions, for example:<br/>
+<span class="name">CollectionAfterInsertion(c2,c1, k1, v1)</span><br/>
+<span class="name">CollectionAfterInsertion(c2,c1, k2, v2)</span><br/>
+ <span class="name">...</span><br/>
+This is interpreted as <em>" <span class="name">c2</span> is the state that results from inserting <span class="name">(k1, v1)</span>, <span class="name">(k2, v2)</span> etc. into <span class="name">c1</span></em></li>
+
+<li> It is possible to have multiple derivations from a single root collection, possibly by different asserters, as shown in the following example.
+
+<div class="anexample">
+<pre class="codeexample">
+ entity(c, [prov:type="EmptyCollection"]) // e is an empty collection
+ entity(k1)
+ entity(v1)
+ entity(k2)
+ entity(v2)
+ entity(k3)
+ entity(v3)
+ entity(c1, [prov:type="Collection"])
+ entity(c2, [prov:type="Collection"])
+ entity(c3, [prov:type="Collection"])
+
+ CollectionAfterInsertion(c1, c, k1, v1) // c1 = { (k1,v1) }
+ CollectionAfterInsertion(c2, c, k2, v2) // c2 = { (k2 v2) }
+ CollectionAfterInsertion(c3, c1, k3,v3) // c3 = { (k1,v1), (k3,v3) }
+</pre>
+</div>
+</li>
+
+<li>Both relations are functional, in the sense that they represent a state change following a unique insertion/removal operation (or a unique set of them). Thus, from the pair of assertions:
+
+<span class="name">CollectionAfterInsertion(c, c1, k1, v1)</span><br/>
+<span class="name">CollectionAfterInsertion(c, c2, k2, v2)</span><br/>
+
+one can infer: <span class="name">c1==c2, k1==k2, v1==v2</span>, because one cannot have two different derivations for the same final collection state.</li>
+
+<li>The following set of insertions:<br/>
+
+<span class="name">CollectionAfterInsertion(c1, c, k, v1)</span><br/>
+<span class="name">CollectionAfterInsertion(c1, c, k, v2)</span><br/>
+
+entails <span class="name">v1==v2</span>.</li>
+
+
+<li> The state of a collection is only known to the extent that a chain of derivations starting from an empty collection can be found. It is understood that a set of assertions regarding a collection's evolution may be incomplete, and therefore so is the reconstructed state obtained by querying those assertions. In general, all assertions reflect the asserter's partial knowledge of a sequence of data transformation events. In the particular case of collection evolution, in which the asserter <em>knows</em> that some of the state changes may have been missed, then the more generic <span class="name">wasDerivedFrom</span> relation should be used to signal that some updates may have occurred, which cannot be precisely asserted as insertions or removals. The following two examples illustrate this.
+
+<div class="anexample">
+<pre class="codeexample">
+ entity(c, [prov:type="collection"]) // e is a collection, possibly not empty
+ entity(k1)
+ entity(v1)
+ entity(k2)
+ entity(v2, [prov:type="collection"]) // v2 is a collection
+
+ CollectionAfterInsertion(c1, c, k1, v1) // c1 <em>includes</em> { (k1,v1) } but may contain additional unknown pairs
+ CollectionAfterInsertion(c2, c1, k2, v2) // c2 includes { (k1,v1), (k2 v2) } where v2 is a collection with unknown state
+</pre>
+</div>
+ In the example, the state of <span class="name">c2</span> is only partially known because the collection is constructed from partially known other collections.
+
+<div class="anexample">
+<pre class="codeexample">
+ entity(c, [prov:type="emptyCollection"]) // e is an empty collection
+ entity(k1)
+ entity(v1)
+ entity(k2)
+ entity(v2)
+
+ CollectionAfterInsertion(c1, c, k1, v1) // c1 = { (k1,v1) }
+ wasDerivedFrom(c2, c1) // the asserted knows that c2 is somehow derived from c1, but cannot assert the precise sequence of updates
+ CollectionAfterInsertion(c3, c2, k2, v2)
+</pre>
+</div>
+Here <span class="name">c3</span> includes <span class="name">{ (k2 v2) }</span> but the earlier "gap" leaves uncertainty regarding <span class="name">(k1,v1)</span> (it may have been removed) or any other pair that may have been added as part of the derivation activities.
+
+</ul>
+
+<p> An assertion CollectionAfterInsertion, written <span class="name"> CollectionAfterInsertion(collAfter, collBefore, key, value)</span>, contains:</p>
+<ul>
+<li><em>entity</em>: an identifier <span class="name">collAfter</span> for the collection record representing the collection <em>after</em> the insertion; </li>
+<li><em>source</em>: an identifier <span class="name">collBefore</span> for the collection record representing the collection <em>before</em> the insertion;</li>
+<li><em>source</em>: an identifier <span class="name">key</span> for the key that has been inserted into <span class="name">collBefore</span></li>
+<li><em>source</em>: an identifier <span class="name">value</span> for the value corresponding to the key that has been inserted into <span class="name">collBefore</span></li>
+</ul>
+
+<p> An assertion CollectionAfterDeletion, written <span class="name"> CollectionAfterDeletion(collAfter, collBefore, key)</span>, contains:</p>
+<ul>
+<li><em>entity</em>: an identifier <span class="name">collAfter</span> for the collection record representing the collection <em>after</em> the deletion; </li>
+<li><em>source</em>: an identifier <span class="name">collBefore</span> for the collection record representing the collection <em>before</em> the deletion;</li>
+<li><em>source</em>: an identifier <span class="name">key</span> for the key corresponding to the (key, value) pair that has been deleted from <span class="name">collBefore</span></li>
+</ul>
+
+
+<p>In PROV-ASN, an collection record's text matches the <span class="nonterminal">collectionRecord</span> production of the grammar:</p>
+<div class='grammar'>
+ <span class="nonterminal">collectionRecord</span> ::=
+<span class="nonterminal">collectionInsertionRecord</span>
+| <span class="nonterminal">collectionRemovalRecord</span>
+<br/>
+
+ <span class="nonterminal">collectionInsertionRecord</span> ::=
+<span class="name">CollectionAfterInsertion</span>
+ <span class="name">(</span>
+ <span class="nonterminal">cidentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">cidentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">kidentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">videntifier</span>
+ <span class="name">)</span>
+ <br/>
+
+ <span class="nonterminal">collectionRemovalRecord</span> ::=
+ <span class="name">CollectionAfterRemoval</span>
+ <span class="name">(</span>
+ <span class="nonterminal">cidentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">cidentifier</span>
+ <span class="name">,</span>
+<span class="nonterminal">kidentifier</span>
+ <span class="name">)</span>
+
+ </div>
+
+
+ </section>
+
+</section>
+
+ <section id="constraints">
+<h2>PROV-DM Constraints</h2>
+
+<p>The previous two sections have introduced a data model for provenance, without introducing any constraint that this data model has to satisfy. In this section, we explore the constraints
+that this data model has to satisfy. </p>
+
+ <section id="interpretation">
+<h3>PROV-DM Interpretation</h3>
+
+<p>Section <a href="#section-time-event">section-time-event</a>
+introduces a notion of <a title="event">instantaneous event</a>
+marking changes in the world, in its activities and entities. PROV-DM
+identifies four kinds of <a title="event">instantaneous events</a>, namely <a>entity generation
+event</a>, <a>entity usage event</a>, <a>activity start event</a>
+and <a>activity end event</a>. PROV-DM adopts Lamport's clock
+assumptions [[CLOCK]] in the form of a reflexive, transitive partial order <a>follows</a>
+(and its inverse <a>precedes</a>) between <a title="event">instantaneous events</a>. Furthermore,
+PROV-DM assumes the existence of a mapping from <a title="event">instantaneous events</a> to time clocks,
+though the actual mapping is not in scope of this specification.</p>
+
+<p>Given that provenance records offer a description of past entities
+and activities, to be meaningful provenance records MUST
+satisfy <em>instantaneous event ordering constraints</em>, which we introduce in
+this section. For instance, an entity can only be used after it was
+generated; hence, we say that an entity's <a title="entity generation
+event">generation event</a> precedes any of this
+entity's <a title="entity usage event">usage event</a>. Should this
+ordering constraint be proven invalid, the associated generation and
+usage records could not be credible. The rest of this section defines
+the <dfn>temporal interpretation</dfn> of provenance records as the
+set of instantaneous event ordering constraints associated with provenance
+records. </p>
+
+
+<p>PROV-DM also allows for time observations to be inserted in
+specific provenance records, for each of the four kinds
+of <a title="event">instantaneous events</a> introduced in this specification. The
+presence of a time observation for a given <a>instantaneous event</a> fixes the
+mapping of this <a>instantaneous event</a> to the timeline. The presence of time
+information in a provenance record instantiates the ordering constraint with
+that time information. It is expected that such instantiated
+constraint can help corroborate provenance information. We anticipate
+that verification algorithms could be developed though this
+verification is outside the scope of this specification.
+</p>
+
+<p>The following figure summarizes the ordering constraints in a
+graphical manner. For each subfigure, an event time line points to the
+right. Activities are represented by rectangles, whereas entities are
+represented by circles. Usage, generation and derivation records are
+represented by the corresponding edges between entities and
+activities. The four kind of <a title="event">instantaneous events</a> are represented by vertical
+dotted lines (adjacent to the vertical sides of an activity's
+rectangle, or intersecting usage and generation edges). The ordering
+constraints are represented by triangles: an occurrence of a triangle between two <a title="event">instantaneous event</a> vertical dotted lines represents that the event denoted by the left
+line precedes the event denoted by the right line.</p>
+
+<div style="text-align: center;">
+<figure>
+<img src="constraints.png" alt="constraints between events" />
+<figcaption id="constraint-summary">Summary of <a title="event">instantaneous event</a> ordering constraints</figcaption>
+</figure>
+</div>
+
+
+<p>The mere existence of an activity assertion entails some <a>event</a> ordering in the world, since an <a>activity start event</a> always <a>precedes</a> the corresponding <a>activity end
+event</a>. This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (a) and expressed by constraint <a href="#start-precedes-end">start-precedes-end</a>.</p>
+
+<div class='interpretation' id='start-precedes-end'> The following ordering constraint holds for any activity record: the
+<a title="activity start event">start event</a> <a>precedes</a> the <a title="activity end event">end event</a>.</div>
+
+<p> Assertion of a usage record and a generation record for a given entity implies ordering of <a title="event">events</a> in the world, since the <a title="entity generation
+event">generation event</a> had to precede the <a title="entity usage event">usage event</a>. This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (b) and expressed by constraint <a href="#generation-precedes-usage">generation-precedes-usage</a>.</p>
+
+<div class='interpretation' id='generation-precedes-usage'>For any entity, the following ordering constraint holds: the <a title="entity generation event">generation</a> of an entity always
+<a>precedes</a> any of its <a title="entity usage event">usages</a>.
+</div>
+
+<p>The assertion of a usage record implies ordering of <a title="event">events</a> in the world, since the corresponding event had to occur during the associated activity. This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (c) and expressed by constraint <a href="#usage-within-activity">usage-within-activity</a>.</p>
+
+<div class='interpretation' id='usage-within-activity'>Given an activity record identified by <span class="name">a</span>, an entity record identified by <span class="name">e</span>, a set
+of attribute-value pairs <span class="name">attrs</span>, and optional time <span class="name">t</span>, <span class='conditional'>if</span>
+ assertion <span class="name">used(a,e,attrs)</span> or <span class="name">used(a,e,attrs,t)</span> holds, <span class='conditional'>then</span> the following ordering constraint holds:
+ the <a title="entity usage event">usage</a> of the entity represented by entity record identified by <span class="name">e</span> <a>precedes</a> the <a title="activity end event">end</a> of
+activity represented by record identified by <span class="name">a</span> and <a>follows</a> its <a title="activity start event">start</a>.
+</div>
+
+
+
+<p>The assertion of a generation record implies ordering of <a title="event">events</a> in the world, since the corresponding event had to occur during the associated activity. This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (d) and expressed by constraint <a href="#generation-within-activity">generation-within-activity</a>.</p>
+
+<div class='interpretation' id='generation-within-activity'><span class='conditional'>If</span> an assertion <span class="name">wasGeneratedBy(x,a,attrs)</span> or <span
+class="name">wasGeneratedBy(x,a,attrs,t)</span> holds, <span class='conditional'>then</span> the following ordering constraint also holds: the <a title="entity generation
+event">generation</a> of the entity denoted by <span class="name">x</span> <a>precedes</a> the <a title="activity end event">end</a>
+of <span class="name">a</span> and <a>follows</a> the <a title="activity start event">start</a> of <span class="name">a</span>.
+</div>
+
+
+
+
+<p>If a derivation record holds for <span class="name">e2</span> and <span class="name">e1</span>, then
+this means that the entity <span class="name">e1</span> had some form of influence on the entity <span class="name">e2</span>; for this to be possible, some event ordering must be satisfied.
+First, we consider one-activity derivations. In that case, the <a title="entity usage event">usage</a> of <span class="name">e1</span> has to precede the <a title="entity generation
+event">generation</a> of <span class="name">e2</span>.
+This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (e) and expressed by constraint <a
+href="#derivation-usage-generation-ordering">derivation-usage-generation-ordering</a>.</p>
+
+
+<div class='interpretation' id='derivation-usage-generation-ordering'>Given an activity record identified by <span class="name">a</span>, entity records identified by <span
+class="name">e1</span> and <span class="name">e2</span>, generation record identified by <span class="name">g2</span>, and usage record identified by <span class="name">u1</span>, <span
+class='conditional'>if</span> the record <span class="name">wasDerivedFrom(e2,e1,a,g2,u1,attrs)</span>
+or <span class="name">wasDerivedFrom(e2,e1,[prov:steps="single"] ∪ attrs)</span> holds, <span class='conditional'>then</span>
+the following ordering constraint holds:
+the <a title="entity usage event">usage</a>
+of entity denoted by <span class="name">e1</span> <a>precedes</a> the <a title="entity generation event">generation</a> of
+the entity denoted by <span class="name">e2</span>.
+</div>
+
+<p>For imprecise-n derivations, a similar constraint exists, but in this case, no usage record can be inferred for <span class="name">e1</span>. Instead, the constraint refers to its
+generation event, as
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (f) and expressed by constraint <a
+href="#derivation-generation-generation-ordering">derivation-generation-generation-ordering</a>.</p>
+
+<div class='interpretation' id='derivation-generation-generation-ordering'>
+Given two entity records denoted by <span class="name">e1</span> and <span class="name">e2</span>, <span class='conditional'>if</span> the record <span
+class="name">wasDerivedFrom(e2,e1,[prov:steps="any"] ∪ attrs)</span>
+ holds, <span class='conditional'>then</span> the following ordering constraint holds:
+the <a title="entity generation event">generation event</a> of the entity denoted by <span class="name">e1</span> <a>precedes</a> the <a title="entity generation event">generation event</a>
+of
+the entity denoted by <span class="name">e2</span>.
+ </div>
+
+<p>Note that event ordering is between generations of <span class="name">e1</span>
+and <span class="name">e2</span>, as opposed to precise-1 derivation,
+which implies ordering ordering between the usage of <span class="name">e1</span> and
+generation of <span class="name">e2</span>. Indeed, in the case of
+imprecise-n derivation, nothing is known about the usage of <span class="name">e1</span>,
+since there is no associated activity.</p>
+
+<p>The assertion of an information flow ordering record between two activities of <span class="name">a1</span> and <span class="name">a2</span> also implies ordering of <a
+title="event">events</a> in the world, since some entity must have been generated by the former and used by the later, which implies that the start event of <span class="name">a1</span>
+cannot follow the end event of <span class="name">a2</span>. This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (g) and expressed by constraint <a href="#wasInformedBy-ordering">wasInformedBy-ordering</a>.</p>
+
+<div class='interpretation' id='wasInformedBy-ordering'>
+Given two activity records denoted by <span class="name">a1</span> and <span class="name">a2</span>, <span class='conditional'>if</span> the record <span
+class="name">wasInformedBy(a2,a1)</span>
+ holds, <span class='conditional'>then</span> the following ordering constraint holds:
+the <a title="activity start event">start event</a> of the activity record denoted by <span class="name">a1</span> <a>precedes</a> the <a title="activity end event">end event</a> of
+the activity record denoted by <span class="name">a2</span>.
+</div>
+
+<p>The assertion of a control flow ordering record between two activities of <span class="name">a1</span> and <span class="name">a2</span> also implies ordering of <a
+title="event">events</a> in the world, since <span class="name">a1</span> must have been active before <span class="name">a2</span> started. This is
+illustrated by Subfigure <a href="#constraint-summary">constraint-summary</a> (h) and expressed by constraint <a href="#wasStartedBy-ordering">wasStartedBy-ordering</a>.</p>
+
+
+<div class='interpretation' id='wasStartedBy-ordering'>
+Given two activity records denoted by <span class="name">a1</span> and <span class="name">a2</span>, <span class='conditional'>if</span> the record <span
+class="name">wasStartedBy(a2,a1)</span>
+ holds, <span class='conditional'>then</span> the following ordering constraint holds: the
+<a title="activity start event">start</a> event of the activity record denoted by <span class="name">a1</span> <a>precedes</a> the <a title="activity start event">start event</a> of
+the activity record denoted by <span class="name">a2</span>.
+</div>
+
+<div class='issue'>In the following, we assume that we can talk about the end of an entity (or agent)
+For this, we use the term 'destruction' This is <a href="http://www.w3.org/2011/prov/track/issues/204">ISSUE-204</a>.
+</div>
+
+
+<p>Further constraints appear in Figure <a href="#constraint-summary2">constraint-summary2</a> and are discussed below.</p>
+
+<div style="text-align: center;">
+<figure>
+<img src="constraints2.png" alt="further constraints between events" />
+<figcaption id="constraint-summary2">Summary of <a title="event">instantaneous event</a> ordering constraints (continued)</figcaption>
+</figure>
+</div>
+
+
+<p>An agent that started an activity must exist when the activity starts.
+This is
+illustrated by Subfigure <a href="#constraint-summary2">constraint-summary2</a> (a) and expressed by constraint <a href="#wasStartedByAgent-ordering">wasStartedByAgent-ordering</a>.</p>
+
+
+<div class='interpretation' id='wasStartedByAgent-ordering'>
+Given an activity denoted by <span class="name">a</span> and an agent denoted by <span class="name">ag</span>, <span class='conditional'>if</span> the record <span
+class="name">wasStartedBy(a,ag)</span>
+ holds, <span class='conditional'>then</span> the following ordering constraints hold: the
+<a title="activity start event">start</a> event of the activity denoted by <span class="name">a</span> <a>follows</a> the <a title="entity generation event">generation event</a> for agent denoted by <span class="name">ag</span>, and
+<a>precedes</a> the destruction event of
+the same agent.
+</div>
+
+
+<p>An activity that was associated with an agent must have some overlap with the agent. The agent may be generated, or may only become associated with the activity, after its start: so, the agent is required to exist before the activity end. Likewise, the agent may be destructed, or may terminate its association with the activity, before the activity end: hence, the agent destruction is required to happen after the activity start.
+This is
+illustrated by Subfigure <a href="#constraint-summary2">constraint-summary2</a> (b) and expressed by constraint <a href="#wasAssociatedWith-ordering">wasAssociatedWith-ordering</a>.</p>
+
+
+<div class='interpretation' id='wasAssociatedWith-ordering'>
+Given an activity denoted by <span class="name">a</span> and an agent denoted by <span class="name">ag</span>, <span class='conditional'>if</span> the record <span
+class="name">wasAssociatedWith(a,ag)</span>
+ holds, <span class='conditional'>then</span> the following ordering constraints hold: the
+<a title="activity start event">start</a> event of the activity denoted by <span class="name">a</span>
+precedes the destruction event of
+the agent denoted by <span class="name">ag</span>, and
+ the <a title="entity generation event">generation event</a> for agent denoted by <span class="name">ag</span>
+<a>precedes</a> the activity <a title="activity end event">end</a> event.
+</div>
+
+
+<div class="issue">
+For completeness, we should define ordering constraint for wasAssociatedWith and actedOnBehalfOf.
+For wasAssociatedWith(a,ag), it feels that ag must have some overlap with a.
+For actedOnBehalfOf(ag1,ag2,a), it seem that ag2 should have existed before the overlap between ag1 and a. This is <a href="http://www.w3.org/2011/prov/track/issues/221">ISSUE-221</a>.
+</div>
+
+
+<div class="issue">
+It is suggested that a stronger name for wasAssociatedWith should be adopted.
+This is <a href="http://www.w3.org/2011/prov/track/issues/182">ISSUE-182</a>.
+</div>
+
+</section>
+
+<section id="structural-constraints">
+<h3>PROV-DM Structural Constraints</h3>
+
+
+
+<p>Sections 5 and 6 define a data model for provenance, which, for the most part, is unconstrained. Section 7.1 defines an interpretation of this data model, in terms of event ordering
+constraints. This section introduces further constraints on the structure of PROV-DM records. Records that satisfy these constraints are said to be <dfn>structurally well-formed</dfn>. A
+benefit of structurally well-formed provenance records is that further inferences can be made, because records are more precise, and therefore, richer. </p>
+
+<p>According to the definition of a <a>generation record</a>, an entity becomes available after this entity's generation event, and does not exist before this event. From this definition,
+we conclude that PROV-DM does not allow for an entity to have two generation records occurring at two different instants.
+The rationale for this constraint is as follows.
+ Two distinct <a title="entity generation event">generation events</a> (by a same activity or by two distinct activities), occurring one after the other, necessarily create two distinct
+entities; otherwise, the second <a title="entity generation event">generation event</a> would have resulted in an entity that existed before its creation, which contradicts the definition of
+<a>generation record</a>.</p>
+
+<p>So, PROV-DM allows for two distinct <a>generation records</a> <span class="name">g1</span> and <span class="name">g2</span> referencing a same entity record provided they occur
+<em>simultaneously</em>.
+<!-- (This means that <span class="name">g1</span> <a>precedes</a> <span class="name">g2</span> and <span class="name">g2</span> <a>precedes</a> <span class="name">g1</span>.) -->
+ In practice, for such a simultaneous generation to occur, the generation event has to be unique and caused by a <em>single world activity</em>, though the provenance records may contain
+different activity records providing alternative descriptions of that same world activity.
+</p>
+
+<div class="anexample">
+<p>
+In the following assertions, a workflow execution <span class="name">a0</span> consists of two sub-workflow executions <span class="name">a1</span> and <span class="name">a2</span>.
+Sub-workflow execution <span class="name">a2</span> generates entity <span class="name">e</span>, so does <span class="name">a0</span>.</p>
+<pre class="codeexample">
+activity(a0,,,[prov:type="workflow execution"])
+activity(a1,,,[prov:type="workflow execution"])
+activity(a2,,,[prov:type="workflow execution"])
+wasInformedBy(a2,a1)
+
+wasGeneratedBy(e,a0)
+wasGeneratedBy(e,a2)
+</pre>
+This example is permitted in PROV-DM if the two activity records <span class="name">a0</span> and <span class="name">a2</span> provide alternate descriptions of what happens in the world
+with respect to this generation event.
+</div>
+
+<p>While this example is permitted in PROV-DM, it does not expose the hierarchical organization of executions and it mixes records providing two descriptions of a same execution. This issue
+is highlighted by two different <a title="generation record">generation records</a> for entity <span class="name">e</span>, which makes reasoning about this kind of provenance records
+unnecessarily difficult. Such assertions are said not be structurally well-formed.</p>
+
+<p>Structurally well-formed provenance records can be obtained by partitioning the generation records into different accounts. This makes it clear that these records provide alternative
+descriptions of the same real-world generation event, rather than describing two generation events for the same entity. When accounts are used, the example can be encoded as follows.</p>
+
+
+<div class="anexample">
+<p>
+The same example is now revisited, with the following assertions that are structurally well-formed. Two accounts are introduced, and there is a single generation record for entity <span
+class="name">e</span> per account.</p>
+<pre class="codeexample">
+account(ex:summary,
+ http://example.org/asserter,
+ activity(a0,t1,t2,[prov:type="workflow execution"])
+ wasGeneratedBy(e,a0))
+
+account(ex:detailed,
+ http://example.org/asserter,
+ activity(a1,t1,t3,[prov:type="workflow execution"])
+ activity(a2,t3,t2,[prov:type="workflow execution"])
+ wasInformedBy(a2,a1)
+ wasGeneratedBy(e,a2))
+</pre>
+</div>
+
+
+
+<!--
+<p>A given entity record can be referred to in a single generation record in the scope of a given <a href="#record-Account">account</a>.
+The rationale for this constraint is as follows.
+If two activities sequentially set different values to some attribute by means of two different <a title="entity generation event">generation events</a>, then they generate distinct
+entities. Alternatively, for two activities to generate an entity simultaneously, they would require some synchronization by which they agree the entity is released for use; the end of this
+synchronization would constitute the actual generation of the entity, but is performed by a single activity. This uniqueness constraint is formalized as follows.
+-->
+
+
+<p>Structurally well-formed records satisfy some constraints, which force the structure of descriptions to be exposed by means of accounts. With these constraints satisfied, further
+inferences can be made about structurally well-formed records.
+The uniqueness of generation records in accounts is formulated as follows.
+</p>
+
+<div class='constraint' id='generation-uniqueness'>Given an entity record denoted by <span class="name">e</span>, two activity records denoted by <span class="name">a1</span> and <span
+class="name">a2</span>, and two sets of attribute-value pairs <span class="name">attrs1</span> and <span class="name">attrs2</span>,
+<span class='conditional'>if</span> the records <span class="name">wasGeneratedBy(e,a1,attrs1)</span> and <span class="name">wasGeneratedBy(e,a2,attrs2)</span> exist in the scope of a given
+account,
+<span class='conditional'>then</span> <span class="name">a1</span>=<span class="name">a2</span> and <span class="name">attrs1</span>=<span class="name">attrs2</span>.
+</div>
+
+
+
+<p>A further inference is permitted from the imprecise-1 derivation record: </p>
+<div class='inference' id='derivation-use'>
+<p>Given an activity record identified by <span class="name">a</span>, entity records identified by <span class="name">e1</span> and <span class="name">e2</span>, and set of attribute-value
+pairs <span class="name">attrs2</span>,
+<span class='conditional'>if</span> <span class="name">wasDerivedFrom(e2,e1, [prov:steps="single"])</span> and <span class="name">wasGeneratedBy(e2,a,attrs2)</span> hold, <span
+class='conditional'>then</span> <span class="name">used(a,e1,attrs1)</span> also holds
+for some set of attribute-value pairs <span class="name">attrs1</span>.
+</div>
+<p>This inference is justified by the fact that the entity represented by entity record identified by <span class="name">e2</span> is generated by at most one activity in a given account
+(see <a href="#generation-uniqueness">generation-uniqueness</a>). Hence, this activity record is also the one referred to in the usage record of <span class="name">e1</span>.
+</p>
+
+
+
+<p>We note that the converse inference, does not hold.
+From <span class="name">wasDerivedFrom(e2,e1)</span> and <span class="name">used(a,e1)</span>, one cannot
+derive <span class="name">wasGeneratedBy(e2,a,attrs2)</span> because identifier <span class="name">e1</span> may occur in usage records referring to
+many activity records, but they may not be referred to in generation records containing identifier <span class="name">e2</span>.</p>
+
+
+<p>
+An account is said to be structurally well-formed if
+it satisfies the constraint <a href="#generation-uniqueness">generation-uniqueness</a>. If an account is structurally well-formed, it support the inference <a
+href="#derivation-use">derivation-use</a>.</p>
+
+<p> The union of two accounts is another account,
+containing the unions of their respective records, where
+ records with a same identifier should be understood according to constraint <a href="#identifiable-record-in-account">identifiable-record-in-account</a>. Structurally well-formed
+accounts are not
+closed under union because the
+constraint <a href="#generation-uniqueness">generation-uniqueness</a> may no
+longer be satisfied in the resulting union. </p>
+
+<p>
+Indeed, let us reconsider example <a href="#account-example-1">account-example-1</a>, and let us define another account record as follows.</p>
+
+<div class="anexample">
+<pre class="codeexample">
+account(ex:acc2,
+ http://example.org/asserter2,
+ entity(e0, [ prov:type="File", ex:path="/shared/crime.txt", ex:creator="Alice" ])
+ ...
+ activity(a1,t1,,[prov:type="createFile"])
+ ...
+ wasGeneratedBy(e0,a1,[ex:fct="create"])
+ ... )
+</pre>
+<p>with identifier <span class="name">ex:acc2</span>, containing assertions by asserter by <span class="name">http://example.org/asserter2</span> stating that the entity represented by
+entity record identified by <span class="name">e0</span> was generated by an activity represented by activity record identified by <span class="name">a1</span> instead of <span
+class="name">a0</span> in the previous account <span class="name">ex:acc0</span>. If accounts <span class="name">ex:acc0</span> and <span class="name">ex:acc2</span> are merged together,
+the resulting set of records violates <a href="#generation-uniqueness">generation-uniqueness</a> if the two activities <span class="name">a0</span> and <span class="name">a1</span> are
+distinct.</p>
+</div>
+
+
+<div class="note">
+Can the semantics characterize better what can be achieved with structurally well-formed accounts?
+</div>
+
+
+<div class="note" id="note-related-to-issue-105">
+Satya discussed the example of a sculpture, whose hand and leg are sculpted independently by two different sculptors. He suggested that the sculpture is generated by two distinct activities.
+This section explains that it is not the case. The example can be formulated as follows.
+
+<p><a href="examples/sculpture.prov-asn">Sculpture example in ASN</a></p>
+
+<p><a href="examples/sculpture.png">Sculpture example image</a></p>
+
+<p>
+We see that ex:s_3 (the sculpture in its final state) was derived from ex:l_2 (containment) which was generated by ex:a2. However, ex:s_3 is not directly generated by ex:a2. We may want to
+consider an abbreviation for this: wasGeneratedBy*(ex:s_3,ex:a2).</p>
+</div>
+
+
+</section>
+
+
+
+</section>
+
+
+
+<section id="resource-section">
+<h2>Resources, URIs, Entities, Identifiers, and Scope</h2>
+
+<p>This specification introduces the notion of an identifiable entity in the world. In PROV-DM, an entity record is a representation of such an identifiable entity. An entity record
+includes an identifier identifying this entity. Identifiers are qualified names, which can be mapped to IRIs. </p>
+
+<p>The term 'resource' is used in a general sense
+ for whatever might be identified by a URI [[!RFC3986]]. On the Web, a URI denotes a resource, without any expectation that the resource is accessed. </p>
+
+<p>The purpose of this section is to clarify the relationship between resource and the notions of entity and entity record. </p>
+
+<p>In the context of PROV-DM, a resource is just a thing in the world. One may take multiple perspectives on such a thing and its situation in the world, fixing some its aspects.</p>
+
+<p> We refer to the <a href="#a-report-example">example</a> of section <a href="#conceptualization">2.1</a> for a resource (at some URL) and three different perspectives, referred to as
+entities. Three different entity records can be expressed for this report, which in the PROV-ASN sample below, are expressed within a same account.
+</p>
+
+<pre>
+container
+prefix app http://example.org/app/
+prefix cr http://example.org/crime/
+
+ account(acc1,
+ http://example.org/asserter1,
+
+ entity(app:0, [ prov:type="Document", cr:path="http://example.org/crime.txt" ])
+ entity(app:1, [ prov:type="Document", cr:path="http://example.org/crime.txt", cr:version="2.1", cr:content="...", cr:date="2011-10-07" ])
+ entity(app:2, [ prov:type="Document", cr:author="John" ])
+ ...)
+endContainer
+</pre>
+
+<p>Each entity record contains an identifier that is unique in
+account <span class="name">acc1</span>, and therefore locally
+identifies the entity record it is contained in. In this example,
+three identifiers were minted.</p>
+
+<p>Given that the report is a resource denoted by the URI <span class="name">http://example.org/crime.txt</span>, we could simply use this URI as the identifier of an entity. This would
+avoid us minting new URIs. Hence, the report URI would play a double role: as a URI it denotes a resource accessible at that URI, and as an identifier in a PROV-DM record, it helps identify
+a specific characterization of this report. A given identifier occurring in an entity record must be unique within the scope of an account. Hence, below, all entities records have been given
+the same identifier but appear in the scope of different accounts, so as to satisfy <a href="#identifiable-record-in-account">identifiable-record-in-account</a>.</p>
+
+<pre>
+container
+prefix app http://example.org/
+prefix cr http://example.org/crime/
+
+ account(acc2,
+ http://example.org/asserter1,
+
+ entity(app:crime.txt, [ prov:type="Document", cr:path="http://example.org/crime.txt" ])
+ ...)
+
+ account(acc3,
+ http://example.org/asserter1,
+
+ entity(app:crime.txt, [ prov:type="Document", cr:path="http://example.org/crime.txt", cr:version="2.1", cr:content="...", cr:date="2011-10-07" ])
+ ...)
+
+ account(acc4,
+ http://example.org/asserter1,
+ entity(app:crime.txt, [ prov:type="Document", cr:author="John" ])
+ ...)
+endContainer
+</pre>
+
+<p>In this case, the qualified name <span class="name">app:crime.txt</span> maps to URI <span class="name">http://example.org/crime.txt</span> still denotes the same resource; however, the
+perspectives we take about that resource are expressed by multiple entity records, happening to all contain the same identifier but in different accounts. </p>
+
+<p> Alternatively, if we need to assert the existence of two different perspectives on the report within the same account, then alternate identifiers MUST be used, one of them being allowed
+to be the resource URI.</p>
+
+<pre>
+container
+ prefix app http://example.org/
+ prefix app2 http://example.org/app/
+ prefix cr http://example.org/crime/
+
+ account(acc5,
+ http://example.org/asserter1,
+
+ entity(app:crime.txt, [ prov:type="Document", cr:path="http://example.org/crime.txt" ])
+ entity(app2:1, [ prov:type="Document", cr:path="http://example.org/crime.txt", cr:version="2.1", cr:content="...", cr:date="2011-10-07" ])
+
+ ...)
+endContainer
+
+</pre>
+
+
+</section>
+
+
+<!--
+<li>For use, generation, and derivation event, the first argument is the 'effect' (i.e. most recent item) and the second argument is the 'cause' (i.e. least recent item). This order is
+compatible with the temporal layout of the graphical notation.
+-->
+
+
+<section class="appendix">
+ <h2>Changes Since Second Public Working Draft</h2>
+<ul>
+<li>01/19/11: Replaced wasComplementOf with alternateOf and specializationOf</li>
+<li>01/16/12: updated derivation, simplified derivation record, prov:strep can be single/any. </li>
+<li>01/02/12: revision of collections </li>
+<li>01/02/12: definition alternate and specialization </li>
+<li>12/21/11: updated example with new relations. </li>
+<li>12/21/11: definition alternate and specialization (5.3.3.3). </li>
+<li>12/21/11: Specified permitted occurrences of prov attributes. </li>
+<li>12/21/11: Introduced the attribute occurrence validity property. </li>
+<li>12/21/11: Clarified the issues with identifier in entity record. </li>
+<li>12/21/11: Explained overloading of wasStartedBy. </li>
+<li>12/21/11: Moved Collections from 6.1 to 6.8. </li>
+<li>12/20/11: Created a section on structural constraints. </li>
+<li>12/19/11: Made plan entity and added extra parameter to wasAssociatedWith. </li>
+<li>12/17/11: Replaced wasComplementOf with viewOf and [foobar] </li>
+<li>12/13/11: Introduced hadPlan as a specialization of wasAssociatedWith. </li>
+<li>12/12/11: Section 7 on interpretation. </li>
+<li>12/08/11: Restructuring of Constraints. </li>
+</ul>
+ </section>
+
+<section class="appendix">
+ <h2>Acknowledgements</h2>
+ <p>
+ WG membership to be listed here.
+ </p>
+ </section>
+
+ </body></html>