--- a/model/ProvenanceModel.html	Wed Sep 14 11:59:15 2011 +0100
+++ b/model/ProvenanceModel.html	Wed Sep 14 12:05:44 2011 +0100
@@ -793,6 +793,10 @@
 in the world; they are just used to help render provenance.
 </p>
 
+<p>
+Name-value pairs occurring in annotations differ from attribute-value pairs (occurring in entity expressions and process execution expressions).  Attribute-value pairs MUST be a representation of something in the world, which remain constant for the duration of the characterization interval (for entity expression) or the activity duration (for process execution expressions). It is OPTIONAL for name-value pairs to be representations  of something in the world. If they are a representation of something in the world, then it MAY change value for the corresponding duration. 
+</p>
+
 
    </section>