--- a/model/ProvenanceModel.html	Tue Jul 26 23:07:33 2011 +0100
+++ b/model/ProvenanceModel.html	Tue Jul 26 23:23:11 2011 +0100
@@ -719,9 +719,8 @@
 
 <p>Use, Generation, and Control assertions MUST contain a role.  Roles
 are mandatory since they allow for uniform data structures.  To facilitate
-the writing of these assertions when roles are unknown by the
-asserter, syntactic notations MAY allow for roles not to be
-expressed. In such a case, a default, uniquely named role from the set
+the writing of these assertions when a role is unknown by the
+asserter, syntactic notations MAY allow these to be written without a role. In such a case, a default, uniquely named role from the set
 'unspecified role' will be assumed; the unspecified roles are
 <b>unspecified0</b>, <b>unspecified1</b>, <b>unspecified2</b>, ....