--- a/model/prov-constraints.html	Thu Jan 31 19:19:07 2013 +0000
+++ b/model/prov-constraints.html	Mon Feb 04 13:12:32 2013 +0100
@@ -944,7 +944,7 @@
 <p> This document defines a subset of PROV instances called
 <i><a>valid</a></i> PROV instances, by analogy with notions of
 validity for other Web standards.
-The intent of validation is ensure that a PROV instance represents a
+The intent of validation is to ensure that a PROV instance represents a
 consistent history of objects and their interactions that is safe to
 use for the purpose of logical reasoning and other kinds of analysis.
 Valid PROV instances satisfy