--- a/model/prov-constraints.html	Mon Jul 16 20:10:33 2012 +0100
+++ b/model/prov-constraints.html	Mon Jul 16 20:13:02 2012 +0100
@@ -581,6 +581,19 @@
 assumptions about time.  Instead, PROV talks about (identified)
 events. </p>
 
+<p>The PROV data model is implicitly based on a notion of <dfn
+  id="dfn-event">instantaneous event</dfn>s (or just <a
+  title="instantaneous event">event</a>s), that mark
+transitions in the world.  Events include generation, usage, or
+invalidation of entities, as well as starting or ending of activities.  This
+notion of event is not first-class in the data model, but it is useful
+for explaining its other concepts and its semantics [[PROV-SEM]].
+Thus, events help justify  <i>inferences</i> on provenance as well as
+<i>validity</i> constraints indicating when provenance is
+  self-consistent.
+
+
+
 <p>Five kinds of <a title="instantaneous event">instantaneous
 events</a> are used in PROV-DM. The <strong>activity start</strong>
 and <strong>activity end</strong> events delimit the beginning and the
@@ -1218,26 +1231,6 @@
     Uniqueness constraints are checked through <a>merging</a> pairs of
     statements.  
 
-<p>The PROV data model is implicitly based on a notion of <dfn
-  id="dfn-event">instantaneous event</dfn>s (or just <a
-  title="instantaneous event">event</a>s), that mark
-transitions in the world.  Events include generation, usage, or
-invalidation of entities, as well as starting or ending of activities.  This
-notion of event is not first-class in the data model, but it is useful
-for explaining its other concepts and its semantics [[PROV-SEM]].
-Thus, events help justify  <i>inferences</i> on provenance as well as
-<i>validity</i> constraints indicating when provenance is
-  self-consistent.
-
-<div class="note">Merge in event descriptions from sec. 8.4</div>
-    
-
-<p>  PROV-DM
-identifies five kinds of <a title="instantaneous event">instantaneous events</a>, namely <a>entity generation
-event</a>, <a>entity usage event</a>, <a>entity invalidation event</a>, <a>activity start event</a>
-and <a>activity end event</a>.  PROV-DM adopts Lamport's clock
-assumptions [[CLOCK]] in the form of a reflexive, transitive partial order <a>precedes</a>
-between <a title="instantaneous event">instantaneous events</a>.  </p>
 
 <div class="note">
   TODO: More about what it means for constraints to be satisfied;