--- a/model/prov-constraints.html	Mon Jul 23 14:12:02 2012 +0100
+++ b/model/prov-constraints.html	Mon Jul 23 14:19:02 2012 +0100
@@ -2906,11 +2906,15 @@
 
 <p id="typing_text">The following rule  establishes types denoted by identifiers from their use within expressions. 
 For this, the function <span class="name">typeOf</span> gives the set of types denoted by an identifier.
-For instance,  <span class="name">typeOf(e)</span> returns the set of types associated with identifier  <span class="name">e</span>. The function <span class="name">typeOf</span> is not a term of PROV, but a construct introduced to validate PROV statements. 
+For example,  <span class="name">typeOf(e)</span> returns the set of types associated with identifier  <span class="name">e</span>. The function <span class="name">typeOf</span> is not a term of PROV, but a construct introduced to validate PROV statements. 
 </p>
 
+
+
+
 <p>
-The following types are recognized: 'entity', 'activity', 'agent', 'prov:Collection', 'prov:EmptyCollection'. For identifiers that do not have a type,  <span class="name">typeOf</span> gives the empty set.
+ For any identifier  <span class="name">id</span>,  <span class="name">typeOf(id)</span>  is a subset of {<span class="name">'entity'</span>, <span class="name">'activity'</span>, <span class="name">'agent'</span>, <span class="name">'prov:Collection'</span>, <span class="name">'prov:EmptyCollection'</span>}.
+For identifiers that do not have a type,  <span class="name">typeOf</span> gives the empty set.
 </p>
 
 <p>To check if a PROV instance satisfies type constraints, one obtains the types of identifiers by application of