--- a/model/prov-dm-constraints.html	Mon Apr 02 11:04:31 2012 +0100
+++ b/model/prov-dm-constraints.html	Mon Apr 02 11:04:42 2012 +0100
@@ -680,9 +680,28 @@
 
 <section id="term-Start">
 <h3>Start</h3>
+
+
+<p>An <a>activity start event</a> is the <a title="event">instantaneous event</a> that marks the instant an activity starts. It allows for an optional time attribute.  Activities also allow for an optional start time attribute.  If both are specified, they MUST be the same, as expressed by the following constraint.
+</p>
+
+<div class='constraint' id='unique-startTime'>
+Given an activity <span class="name">activity(a,t1,t2,attrs1)</span> and its start <span class="name">wasStartedBy(id,a,e,t,attrs2)</span>,  then <span class="name">t</span>=<span class="name">t1</span>.
+</div> 
 </section> 
+
 <section id="term-End">
 <h3>End</h3>
+
+
+<p>An <a>activity end event</a> is the <a title="event">instantaneous event</a> that marks the instant an activity ends. It allows for an optional time attribute.  Activities also allow for an optional end time attribute.  If both are specified, they MUST be the same, as expressed by the following constraint.
+</p>
+
+<div class='constraint' id='unique-endTime'>
+Given an activity <span class="name">activity(a,t1,t2,attrs1)</span> and its end <span class="name">wasEndedBy(id,a,e,t,attrs2)</span>,  then <span class="name">t</span>=<span class="name">t2</span>.
+</div> 
+
+
 </section> 
 
 
@@ -691,7 +710,7 @@
 
 
 
-<p> An information flow ordering relation is formally defined as follows.</p>
+<p>Communication is formally defined as follows.</p>
 
 <div class='constraint' id='wasInformedBy-Definition'>Given two activities identified by <span class="name">a1</span> and <span class="name">a2</span>, 
  <span class="name">wasInformedBy(a2,a1)</span>
@@ -701,12 +720,13 @@
 </div>
 
 
+<p>
 <div class="interpretation-forward">
 For the interpretation of an information flow ordering, see <a href="#wasInformedBy-ordering">wasInformedBy-ordering</a>.
 </div>
 
 
-<p>The relationship <span class="name">wasInformedBy</span> is not transitive. Indeed, consider the following fragment.</p>
+<p>The relationship <span class="name">wasInformedBy</span> is not transitive. Indeed, consider the following descriptions.</p>
 <pre class="codeexample">
 wasInformedBy(a2,a1)
 wasInformedBy(a3,a2)
@@ -727,7 +747,17 @@
 </figure>
 </div>
 
-<p>Control ordering between two activities denoted by <span class="name">a2</span> and <span class="name">a1</span> is specified as follows.</p>
+</section>
+
+
+
+
+<section id="term-StartByActivity">
+<h3>Start by Activity</h3>
+</section> 
+
+
+<p>Start of <span class="name">a2</span> by activity <span class="name">a1</span> is specified as follows.</p>
 
 <div class='constraint' id='wasStartedBy'>Given two activities with identifiers <span class="name">a1</span> and <span class="name">a2</span>, 
  <span class="name">wasStartedBy(a2,a1)</span>
@@ -739,22 +769,14 @@
  and <span class="name">wasStartedBy(a2,e,sAttr)</span> hold.
 </div>
 
-<p>We note that an activity start associates an activity with an agent, and is denoted by the name <span class="name">wasStartedBy</span>.  A <a>control ordering</a> relation associates an
-activity with another activity, also denoted by the name <span class="name">wasStartedBy</span>. Effectively, by considering both relation types, the relation <span
-class="name">wasStartedBy</span> has a range formed by the union of agents and activities.</p>
-
-
+
+<p>
 
 <div class="interpretation-forward">
 For the interpretation of a control flow ordering, see <a href="#wasStartedBy-ordering">wasStartedBy-ordering</a>.
 </div>
 
 
-</section>
-
-<section id="term-StartByActivity">
-<h3>Start by Activity</h3>
-</section> 
 
    </section>