--- a/model/constraints-blog.html Sat Sep 08 13:48:40 2012 +0100
+++ b/model/constraints-blog.html Sat Sep 08 14:01:05 2012 +0100
@@ -4,13 +4,12 @@
<h2>Last Call: Constraints of the Provenance Data Model</h2>
-<p>On Sept. XX, 2012 the Provenance Working Group has announced Last Call on a new document in the suite that defines the core of the PROV family of specifications: <a href="http://www.w3.org/TR/prov-constraints/">PROV-CONSTRAINTS</a>.</p>
+<p>On Sept. XX, 2012 the Provenance Working Group has announced Last Call on a new document: <a href="http://www.w3.org/TR/prov-constraints/">PROV-CONSTRAINTS</a> in the suite that defines the core of the PROV family of specifications.</p>
<p>This follows the recent <a href="http://www.w3.org/blog/SW/2012/07/24/last-call-3-working-drafts-for-provenance-interchange/">Last Call announcement for 3 other documents</a>, namely <a href="http://www.w3.org/TR/prov-dm/">PROV-DM<a>, <a href="http://www.w3.org/TR/prov-o/">PROV-O<a>, <a href="http://www.w3.org/TR/prov-n/">PROV-N<a>. The meaning of <em>Last Call</em> is clarified in the earlier announcement. Essentially, it means that the specification document is open to public comments for a set period of time, at the end of which the editors commit to produce the final version of the document, where all such comments are accounted for following internal group discussions.</p>
<p> The <a href="http://www.w3.org/TR/prov-constraints/">PROV-CONSTRAINTS</a> document complements the first three, and is focused on the notion of <em>valid</em> provenance. The intent of provenance validation is to ensure that a set of PROV statements, called a <strong>PROV instance</strong>, represents a history of objects and their interactions which is consistent, and thus safe to use for the purpose of logical reasoning and other kinds of analysis.
- Valid PROV statements satisfy the all definitions, inferences, and constraints found in the The <a href="http://www.w3.org/TR/prov-constraints/">PROV-CONSTRAINTS</a> document. </p>
-<p>
+ Valid PROV statements satisfy all the definitions, inferences, and constraints found in the The <a href="http://www.w3.org/TR/prov-constraints/">PROV-CONSTRAINTS</a> document.
Thus, the document can be used for two main purposes:
@@ -52,7 +51,7 @@
<code>IF wasGeneratedBy(gen; e,_a1,_t1,_attrs1) and used(use; _a2,e,_t2,_attrs2) THEN gen precedes use.</code></p>
-<li><strong>Impossibiliy constraints</strong>. These are used to state for example that the same identifier cannot be used in two different relation types (i.e. <code>entity(foo)</code> and <code>activity(foo)</code> is an illegal combination), but also to state property of relations, for example "specialization is irreflexive" (<a href="http://www.w3.org/TR/prov-constraints#impossible-specialization-reflexive">Constraint 54</a>): </p>
+<li><strong>Impossibility constraints</strong>. These are used to state for example that the same identifier cannot be used in two different relation types (i.e. <code>entity(foo)</code> and <code>activity(foo)</code> is an illegal combination), but also to state property of relations, for example "specialization is irreflexive" (<a href="http://www.w3.org/TR/prov-constraints#impossible-specialization-reflexive">Constraint 54</a>): </p>
<code> IF specializationOf(e,e) THEN INVALID.</code></p>
and "the set of entities and activities are disjoint" (<a href="http://www.w3.org/TR/prov-constraints#entity-activity-disjoint">Constraint 57</a>):</p>
<code>IF 'entity' ∈ typeOf(id) AND 'activity' ∈ typeOf(id) THEN INVALID.</code></p>