--- a/REC-drafts/NOTE-rdf11-primer-20140225/Overview.html Mon Feb 24 12:26:32 2014 +0100
+++ b/REC-drafts/NOTE-rdf11-primer-20140225/Overview.html Mon Feb 24 12:28:38 2014 +0100
@@ -394,7 +394,10 @@
<h2 aria-level="1" role="heading" id="h2_section-Introduction"><span class="secno">1. </span>Introduction</h2>
<p>The Resource Description Framework (RDF) is a framework for
- expressing information about <strong id="resource">resources</strong>. Resources
+ expressing information about
+ <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#resources-and-statements">
+ resources</a>.
+ Resources
can be anything, including documents, people, physical objects, and abstract
concepts.</p>
@@ -429,7 +432,7 @@
[<cite><a class="bibref" href="#bib-RDF11-CONCEPTS">RDF11-CONCEPTS</a></cite>]</li>
<li>A document describing the formal model-theoretic semantics
of RDF ("RDF Semantics") [<cite><a class="bibref" href="#bib-RDF11-MT">RDF11-MT</a></cite>]</li>
- <li>Specifications of concrete syntaxes for RDF:
+ <li>Specifications of serialization formats for RDF:
<ul>
<li>Turtle [<cite><a class="bibref" href="#bib-TURTLE">TURTLE</a></cite>] and TriG [<cite><a class="bibref" href="#bib-TRIG">TRIG</a></cite>]</li>
<li>JSON-LD [<cite><a class="bibref" href="#bib-JSON-LD">JSON-LD</a></cite>] (JSON based)</li>
@@ -571,7 +574,7 @@
<p>The abbreviation IRI is short for "International Resource
- Identifier". An <a href="http://www.w3.org/TR/rdf11-concepts/#section-IRIs">IRI</a>
+ Identifier". An <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-IRIs">IRI</a>
identifies a resource. The URLs (Uniform Resource Locators) that
people use as Web addresses are one form of IRI. Other forms of IRI
provide an identifier for a resource without implying its location
@@ -612,14 +615,14 @@
<h3 aria-level="2" role="heading" id="h3_section-literal"><span class="secno">3.3 </span>Literals</h3>
<p>
- <a href="http://www.w3.org/TR/rdf11-concepts/#section-Graph-Literal">Literals</a>
+ <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-Graph-Literal">Literals</a>
are basic values that are not IRIs. Examples of literals include
strings such as "La Joconde", dates such as "the 4th of July, 1990"
and numbers such as "3.14159".
- Literals are associated with a <i>datatype</i> enabling such
- values to be parsed and interpreted correctly.
- String literals can optionally be associated with a <i>language
- tag</i>. For example, "Léonard de Vinci" could
+ Literals are associated with a <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-Datatypes">datatype</a>
+ enabling such values to be parsed and interpreted correctly.
+ String literals can optionally be associated with a <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-Graph-Literal">language
+ tag</a>. For example, "Léonard de Vinci" could
be associated with the "fr" language tag and "李奥纳多·达·文西"
with the "zh" language tag.</p>
@@ -628,7 +631,7 @@
<p class="note">The 2004 version of RDF contained the notion of a
"plain literal" with no datatype. This feature has been removed, as the
distinction between "plain" literals and literals with datatype
- <code>string</code> was confusing. RDF syntaxes such as Turtle allow
+ <code>string</code> was confusing. RDF languages such as Turtle allow
writing of literals without an explicit datatype and treat this
as syntactic sugar for a <code>string</code>
datatype. The special datatype
@@ -640,7 +643,7 @@
<p>Literals may only appear in the <strong>object position</strong> of a triple.</p>
<p>The RDF Concepts document provides a (non-exhaustive)
- <a href="http://www.w3.org/TR/rdf11-concepts/#section-Datatypes">list
+ <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-Datatypes">list
of datatypes</a>. This includes many datatypes defined by XML
Schema, such as string, boolean, integer, decimal and date. </p>
@@ -655,9 +658,9 @@
to be able to talk about resources without bothering to use a global
identifier. For example, we might want to state that the Mona
Lisa painting has in its background an unidentified tree which
- we know to be a cypress tree. Resources without identifiers such as the
- painting's cypress tree can be represented by <a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes">"blank
- nodes"</a> in RDF. Blank nodes are like simple
+ we know to be a cypress tree. A resource without a global identifier, such as the
+ painting's cypress tree, can be represented in RDF by a <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-blank-nodes">blank
+ nodes</a>. Blank nodes are like simple
variables in algebra; they represent some thing without saying
what their value is.
</p>
@@ -681,7 +684,7 @@
<h3 aria-level="2" role="heading" id="h3_section-multiple-graphs"><span class="secno">3.5 </span>Multiple graphs</h3>
<p>RDF provides a mechanism to group RDF statements in multiple
- graphs and associate graphs with an IRI . Multiple graphs are a recent extension of the RDF
+ graphs and associate such graphs with an IRI . Multiple graphs are a recent extension of the RDF
data model. In practice, RDF tool builders and data managers
needed a mechanism to talk about subsets of a collection of
triples. Multiple graphs were first introduced in the RDF query
@@ -690,12 +693,12 @@
<p>Multiple graphs in
an RDF document constitute an
- <a href="http://www.w3.org/TR/rdf11-concepts/#section-dataset">RDF
+ <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-dataset">RDF
dataset</a>. An RDF dataset may have multiple named graphs and
at most one unnamed ("default") graph. </p><p>
</p><p>For example, the
- statements in the <a href="#example1">Example 1</a>
+ statements in <a href="#example1">Example 1</a>
could be grouped in two named
graphs. A first graph could be provided by a social networking
site and identified by <code>http://example.org/bob</code>:</p>
@@ -706,7 +709,8 @@
<Bob> <is interested in> <the Mona Lisa>.</pre></div>
<p>The IRI associated with the graph is
- called the "graph name" [<cite><a class="bibref" href="#bib-RDF11-CONCEPTS">RDF11-CONCEPTS</a></cite>]. </p>
+ called the <a href="http://www.w3.org/TR/2014/REC-rdf11-concepts-20140225/#section-dataset">graph
+ name</a>. </p>
<p>A second graph could be provided by <a href="http://www.wikidata.org/">Wikidata</a>
and identified by
@@ -729,10 +733,11 @@
<code><http://example.org/bob></code> we would get access to the four triples
in that graph.</p>
- <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_1"><span>Note</span></div><p class="">RDF provides no way to convey this semantic
+ <div class="note"><div class="note-title" aria-level="3" role="heading" id="h_note_1"><span>Note</span></div><p class="">RDF provides no standard way to convey this semantic
assumption (i.e., that graph names represent the source of the
RDF data) to other readers of the dataset. Those readers will
- need to rely on out-of-band knowledge to interpret the dataset
+ need to rely on out-of-band knowledge, such as established
+ community practice, to interpret the dataset
in the intended way. Possible semantics of datasets are described in a separate note
[<cite><a class="bibref" href="#bib-RDF11-DATASETS">RDF11-DATASETS</a></cite>]. </p></div>
@@ -762,7 +767,7 @@
resources. </p>
<p>To support the definition of vocabularies RDF provides
- the RDF-Schema language
+ the RDF Schema language
[<cite><a class="bibref" href="#bib-RDF11-SCHEMA">RDF11-SCHEMA</a></cite>]. This language allows one to define semantic
characteristics of
RDF data. For example, one can state that the IRI
@@ -773,13 +778,13 @@
</p><p>RDF Schema uses the notion of <strong>class</strong> to
specify categories that can be used to classify resources. The
relation between an instance and its class is stated through the
- <strong>type</strong> property. One can create create hierarchies
+ <strong>type</strong> property. With RDF Schema one can create hierarchies
of classes and sub-classes and of
properties and sub-properties. Type restrictions on the subjects
and objects of particular triples can be defined through
<strong>domain</strong> and <strong>range</strong>
restrictions. An example of a domain restriction was given above:
- subjects of "friendOf" triples should be ofn class "Person".</p>
+ subjects of "friendOf" triples should be of class "Person".</p>
<p>The main modeling
constructs provided by RDF Schema are summarized in the table below:</p>
@@ -853,13 +858,13 @@
<a href="#example1">Example 1</a>), properties like this are themselves resources that can be
described by triples or provide values in the descriptions of other
resources. In this example, <code><is a friend of></code> is the subject of triples
-that assign type, domain, and range values to it, and it's the object of
+that assign type, domain, and range values to it, and it is the object of
a triple that describes something about the <code><is a good friend of></code>
property.
-</p><p>One of first RDF vocabularies used worldwide was the
+</p><p>One of the first RDF vocabularies used worldwide was the
<a href="http://www.foaf-project.org/">"Friend of a Friend"</a> (FOAF)
-vocabulary for describing social networks. Other typical examples of RDF
+vocabulary for describing social networks. Other examples of RDF
vocabularies are:</p>
<dl>
@@ -902,11 +907,11 @@
<!--OddPage-->
<h2 aria-level="1" role="heading" id="h2_section-graph-syntax"><span class="secno">5. </span>Writing RDF graphs</h2>
- <p>Many different concrete syntaxes exist for writing down RDF
+ <p>A number of different serialization formats exist for writing down RDF
graphs. However, different ways of writing down the same graph lead
to exactly the same triples, and are thus logically equivalent. </p>
- <p>In this section we briefly introduce, through annotated examples, the following syntaxes:</p>
+ <p>In this section we briefly introduce, through annotated examples, the following formats:</p>
<ol>
<li>Turtle family of RDF languages
(<a href="#section-n-triples">N-Triples</a>,
@@ -919,14 +924,15 @@
</ol>
<div class="note"><div class="note-title" aria-level="2" role="heading" id="h_note_3"><span>Note</span></div><p class="">
-Tip: we suggest to read Sec. 5.1 on the Turtle-related syntaxes and to read
-the sections on JSON-LD, RDFa and RDF/XML only when you are
+Reading tip: Sec. 5.1 (Turtle <em>et al.</em>) discusses all
+basic concepts for serializing RDF. We suggest you
+read the sections on JSON-LD, RDFa and RDF/XML only if you are
interested in that particular usage of RDF. </p></div>
<section id="section-turtle-family" typeof="bibo:Chapter" resource="#ref" rel="bibo:Chapter">
<h3 aria-level="2" role="heading" id="h3_section-turtle-family"><span class="secno">5.1 </span>Turtle family of RDF languages</h3>
-<p>In this subsection we introduce four concrete syntaxes for RDF
+<p>In this subsection we introduce four RDF languages
which are closely related. We start with N-Triples, as it provides
basic syntax for writing down RDF triples. The Turtle syntax
extends this basic syntax with various forms of syntactic sugar to improve
@@ -973,7 +979,7 @@
<p>The figure below shows the triples resulting from the example:</p>
<figure id="fig4">
- <img alt="Graph of the sample triples" src="example-graph-iris.jpg" class="graph" />
+ <img alt="Graph of the sample triples" src="example-graph-iris.jpg" style="width: 75%" />
<figcaption>Fig. <span class="figno">4</span> <span class="fig-title">RDF graph resulting from the N-Triples example</span></figcaption>
</figure>
@@ -1021,7 +1027,7 @@
<p>The Turtle example is logically equivalent to the <a href="#n-triples-example">N-Triples</a>
example. Lines 1-6 contain a number of directives which provide shorthands for
writing down IRIs. Relative IRIs (such as <code>bob#me</code> on line 8) are
-resolved agains a base IRI, specified here in line 1.
+resolved against a base IRI, specified here in line 1.
Lines 2-6 define IRI prefixes (such as <code>foaf:</code>), which can
be use for prefixed names (such as <code>foaf:Person</code>) instead of full IRIs.
The corresponding IRI is constructed by replacing the prefix with its
@@ -1046,7 +1052,7 @@
<h4 id="representation-of-blank-nodes">Representation of blank nodes</h4>
-<p>Below is syntactic variants for writing down blank nodes, using the
+<p>Below we see two syntactic variants for writing down blank nodes, using the
earlier cypress tree example:</p>
<div class="example"><div class="example-title"><span>Example 8</span>: Blank node</div><pre class="example">PREFIX lio: <http://purl.org/net/lio#>
@@ -1061,7 +1067,7 @@
for the informal graph in <a href="#fig2" class="fig-ref">Fig. 2</a>.</p>
<p>Turtle also has an alternative notation for blank nodes, which
-does not require the use of the syntax like <code>_:x</code>: </p>
+does not require the use of syntax like <code>_:x</code>: </p>
<div class="example"><div class="example-title"><span>Example 9</span>: Blank nodes (alternative notation)</div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
@@ -1072,7 +1078,7 @@
dcterms:title "Mona Lisa" ;
dcterms:creator <http://dbpedia.org/resource/Leonardo_da_Vinci> ] .</pre></div>
-<p>Square brackets represent a blank node. Predicate-object pairs within
+<p>Square brackets represent here a blank node. Predicate-object pairs within
the square brackets are interpreted as triples with the blank node as
subject. Lines starting with '#' represent
comments. </p>
@@ -1144,7 +1150,7 @@
<p>The figure below shows the triples resulting from this example.</p>
<figure id="fig5">
- <img alt="Triples resulting from the TriG example" src="example-multiple-graphs-iris.jpg" class="graph" />
+ <img alt="Triples resulting from the TriG example" src="example-multiple-graphs-iris.jpg" style="width: 75%" />
<figcaption>Fig. <span class="figno">5</span> <span class="fig-title">Triples resulting from the TriG example</span></figcaption>
</figure>
</section>
@@ -1221,7 +1227,7 @@
<code>http://example.org/bob#me</code>, as
specified on line 3, through the use of the <code>@id</code> keyword.
The <code>@id</code> keyword, when used as a key in a JSON-LD document, points
- to an IRI identifying the resource corresponding to the parent JSON object.
+ to an IRI identifying the resource corresponding to the current JSON object.
We describe the type of this resource on line 4, its birth date
on line 5 and one of its friends on line 6. From line 7 to 12 we describe
one of its interests, the Mona Lisa painting.</p>
@@ -1260,7 +1266,7 @@
<span class="linenum">25</span> }</pre></div>
<p>This context describes how a JSON-LD document can be mapped
- to an RDF graph. On lines 4 to 9 it will describe how to map
+ to an RDF graph. Lines 4 to 9 specify how to map
<code>Person</code>, <code>interest</code> and <code>knows</code>
to types and properties in the FOAF namespace defined
on line 3. We also specify on line 8 that the <code>knows</code>
@@ -1273,10 +1279,10 @@
<p>From line 16 to line 23 we describe how to map
<code>title</code>, <code>creator</code> and <code>subject_of</code>
- to Dublin Core property IRIs. In particular the <code>@reverse</code>
- keyword on line 21 means that whenever we
+ to Dublin Core property IRIs. The <code>@reverse</code>
+ keyword on line 21 is used to specify that, whenever we
encounter <code>"subject_of": "x"</code> in a JSON-LD document using this
- context we will map it to an RDF triple which subject is the <code>x</code>
+ context, we should map it to an RDF triple which subject is the <code>x</code>
IRI, which property is <code>dcterms:subject</code> and
which object is the resource corresponding to the parent JSON object.</p>
@@ -1382,10 +1388,10 @@
<h3 aria-level="2" role="heading" id="h3_section-rdfxml"><span class="secno">5.4 </span>RDF/XML</h3>
<p>RDF/XML [<cite><a class="bibref" href="#bib-RDF-SYNTAX-GRAMMAR">RDF-SYNTAX-GRAMMAR</a></cite>] provides an XML syntax for RDF
-graphs. When RDF was original developed in the late 1990s, this was its
+graphs. When RDF was originally developed in the late 1990s, this was its
only syntax, and some people still call this syntax "RDF". In 2001, a
precursor to Turtle called "N3" was proposed, and gradually the other
-syntaxes listed here have been adopted and standardized. </p>
+languages listed here have been adopted and standardized. </p>
<p>The RDF/XML example below encodes the
RDF graph depicted in <a href="#fig4" class="fig-ref">Fig. 4</a>:</p>
@@ -1469,7 +1475,7 @@
<li>The IRIs used to name the subject, predicate, and object are "global" in scope,
naming the same thing each time they are used.</li>
<li>Each triple is "true" exactly when the predicate relation actually exists between
- the subject and the predicate.</li>
+ the subject and the object.</li>
<li>An RDF graph is "true" exactly when all the triples in it are "true".</li>
</ol>
<p>These notions,
@@ -1481,7 +1487,7 @@
certain set of input triples which they accept as true, systems
can in some circumstances deduce that other triples must,
logically, also be true. We say the first set of triples "entails"
- the additional triples. These systems, called Reasoners, can also
+ the additional triples. These systems, called "reasoners", can also
sometimes deduce that the given input triples contradict each
other. </p>
@@ -1489,13 +1495,13 @@
created when people want to use new concepts, there are many
different kinds of reasoning one might want to do. When a
specific kind of reasoning seems to be useful in many different
- applications, it can be documented as an <a href="http://www.w3.org/TR/rdf11-mt/#semantic-extensions-and-entailment-regimes">"entailment regime"</a>.
+ applications, it can be documented as an <a href="http://www.w3.org/TR/rdf11-mt/#semantic-extensions-and-entailment-regimes">entailment regime</a>.
Several entailment regimes are specified in RDF Semantics. For
- technical description of some other entailment regimes and how to
- use them with SPARQL, see [<cite><a class="bibref" href="#bib-SPARQL11-ENTAILMENT">SPARQL11-ENTAILMENT</a></cite>].
+ technical descriptions of some other entailment regimes and how to
+ use these with SPARQL, see [<cite><a class="bibref" href="#bib-SPARQL11-ENTAILMENT">SPARQL11-ENTAILMENT</a></cite>].
Note that some
entailment regimes are fairly easy to implement and reasoning can
- be done quickly, while others require a very sophistical
+ be done quickly, while others require sophisticated
techniques to implement efficiently. </p>
<p>As a sample entailment, consider the following two statements:</p>
@@ -1547,8 +1553,8 @@
<p>RDF allows you to combine triples from any source into a graph
and process it as legal RDF. A large amount of RDF data is
- available as part of the Linked
- Data [<cite><a class="bibref" href="#bib-LINKED-DATA">LINKED-DATA</a></cite>] cloud. Datasets are being published and
+ available as Linked
+ Data [<cite><a class="bibref" href="#bib-LINKED-DATA">LINKED-DATA</a></cite>]. Datasets are being published and
interlinked on the Web using RDF, and many of them offer a
querying facility through SPARQL [<cite><a class="bibref" href="#bib-SPARQL11-OVERVIEW">SPARQL11-OVERVIEW</a></cite>]. Examples
of such datasets used in the examples above include:</p>
@@ -1563,7 +1569,7 @@
<li><a href="http://www.w3.org/2006/03/wn/wn20/">WordNet</a>,
a lexical database of English terms, grouped in sets
- of synonyms, with a range of semantic interrelations.Similar
+ of synonyms, with a range of semantic interrelations. Similar
databases exist for other languages.</li>
<li><a href="http://www.europeana.eu/">Europeana</a>, publishing
@@ -1575,7 +1581,7 @@
libraries and other agencies.</li>
</ul>
- <p>A list of datasets available within the Linked Data cloud is maintained at
+ <p>A list of datasets available as Linked Data is maintained at
<a href="http://datahub.io/dataset">datahub.io</a>.</p>
<p>A number of vocabulary terms have become popular for
@@ -1624,7 +1630,7 @@
Hayes, Ivan Herman, Kingsley Idehen, Antoine Isaac, Markus Lanthaler, and David Wood. </p>
-<p>The introduction contains a number of sentences from the
+<p>The introduction of this document contains a number of sentences from the
2004 Primer [<cite><a class="bibref" href="#bib-RDF-PRIMER">RDF-PRIMER</a></cite>]. For the rest the RDF 1.1 Primer is a completely
new document.</p>