--- a/model/prov-constraints.html	Mon Jul 23 13:31:09 2012 +0100
+++ b/model/prov-constraints.html	Mon Jul 23 13:58:53 2012 +0100
@@ -2905,7 +2905,7 @@
 <h2>Type Constraints</h2>
 
 <p id="typing_text">The following rule  establishes types denoted by identifiers from their use within expressions. 
-The following types are recognized: 'entity', 'activity', 'agent', 'prov:Collection', 'prov:EmptyCollection'.</p>
+The following types are recognized: 'entity', 'activity', 'agent', 'prov:Collection', 'prov:EmptyCollection'. An identifier may denote multiple types, hence <span class="name">typeOf(id)</span> is the set of types denoted by <span class="name">id</span>. </p>
 
 <div class='constraint' id="typing">