--- a/model/prov-n.html Thu Apr 19 23:28:35 2012 +0100
+++ b/model/prov-n.html Thu Apr 19 23:42:34 2012 +0100
@@ -1,4 +1,4 @@
-<!DOCTYPE html>
+ <!DOCTYPE html>
<html><head>
<title>PROV-N: The Provenance Notation</title>
@@ -423,6 +423,7 @@
<br/>
| <span class="nonterminal">startExpression</span>
| <span class="nonterminal">endExpression</span>
+| <span class="nonterminal">invalidationExpression</span>
| <span class="nonterminal">communicationExpression</span>
| <span class="nonterminal">startByActivityExpression</span>
<br/>
@@ -792,6 +793,52 @@
at least one of <span class='attribute'>trigger</span>, <span class='attribute'>time</span>, and <span class='attribute'>attributes</span> MUST be present.</p>
</section>
+<section id="expression-Invalidation">
+<h4>Invalidation</h4>
+
+
+<div class="withPn">
+
+<div class='grammar'>
+<span class="nonterminal">invalidationExpression</span> ::=
+<span class="name">wasInvalidatedBy</span>
+<span class="name">(</span>
+<span class="optional">( <span class="nonterminal">identifier</span> | <span class="name">-</span> ) <span class="name">,</span> </span>
+<span class="nonterminal">eIdentifier</span>
+<span class="name">,</span>
+( <span class="nonterminal">aIdentifier</span> | <span class="name">-</span> )
+<span class="name">,</span> ( <span class="nonterminal">time</span> | <span class="name">-</span> )
+<span class="nonterminal">optional-attribute-values</span>
+<span class="name">)</span><br/>
+</div>
+</div>
+
+<div class="anexample">
+
+<pre class="codeexample">
+wasInvalidatedBy(ex:i1, tr:WD-prov-dm-20111215, ex:edit1, 2011-11-16T16:00:00, [ex:fct="save"])
+</pre>
+<p> Here <span class="name">ex:i1</span> is the optional invalidation identifier, <span class="name">tr:WD-prov-dm-20111215</span> is the identifier of the entity being invalidated,
+ <span class="name">ex:edit1</span> is the optional identifier of the invalidating activity, <span class="name">2011-11-16T16:00:00</span> is the optional invalidation time, and <span class="name"> [ex:fct="save"]</span> are optional attributes. </p>
+The remaining examples show cases where some of the optionals are omitted.
+
+<pre class="codeexample">
+wasInvalidatedBy(tr:WD-prov-dm-20111215, ex:edit1, -)
+wasInvalidatedBy(tr:WD-prov-dm-20111215, ex:edit1, 2011-11-16T16:00:00)
+wasInvalidatedBy(e2, a1, -, [ex:fct="save"])
+wasInvalidatedBy(e2, -, -, [ex:fct="save"])
+wasInvalidatedBy(ex:i1, tr:WD-prov-dm-20111215, ex:edit1, -)
+wasInvalidatedBy(-, tr:WD-prov-dm-20111215, ex:edit1, -)
+</pre>
+</div>
+
+<p>Even though the production <span class="nonterminal">invalidationExpression</span> allows for expressions <span class="name">wasInvalidatedBy(e2, -, -)</span> and <span class="name">wasInvalidatedBy(-, e2, -, -)</span>, these expressions are not valid in PROV-N, since
+at least one of <span class='attribute'>activity</span>, <span class='attribute'>time</span>, or <span class='attribute'>attributes</span> MUST be present.</p>
+
+
+</section>
+
+
<section id="expression-wasInformedBy">
<h4>Communication</h4>