--- a/model/prov-n.html	Wed Jul 11 14:36:29 2012 +0100
+++ b/model/prov-n.html	Wed Jul 11 16:10:38 2012 +0100
@@ -2096,6 +2096,26 @@
 </section>
 
 -->
+<section id="exceptions-summary">
+<h3>Summary of additional validity rules for grammar productions</h3>
+
+<div style="text-align: left;">
+<table border="1" style="margin-left: auto; margin-right: auto;">
+<caption id="validity-rules-table">Summary of additonal rules for grammar productions</caption>
+<tr><td><a><b>Production</b></a></td>
+     <td><b>Syntactically correct forms</b></td>
+     <td><b>Additional semantic rule</b></td>
+</tr>
+<tr><td><a class="grammarRef" href="#prod-generationExpression">Generation expression</a></td>
+    <td><span class="name">wasGeneratedBy(e2, -, -)</span><p/><span class="name">wasGeneratedBy(-; e2, -, -)</span></td>
+    <td>At least one  of <a href="http://www.w3.org/TR/prov-dm/#generation.id"><span class='attribute'>id</span></a>, <a href="http://www.w3.org/TR/prov-dm/#generation.activity"><span class='attribute'>activity</span></a>, <a href="http://www.w3.org/TR/prov-dm/#generation.time"><span class='attribute'>time</span></a>, and  <a href="http://www.w3.org/TR/prov-dm/#generation.attributes"><span class='attribute'>attributes</span></a> MUST be present.</td>  
+</tr>
+</table>
+</div>
+
+
+
+</section>
 
 <section  id="subexpressions">
 <h3>Further Expressions</h3>
@@ -2103,8 +2123,6 @@
 This section defines further expressions of PROV-N.
 
 
-
-
 <section id="expression-identifier">
 <h4>Identifier</h4>