--- a/model/ProvenanceModel.html	Tue Nov 29 09:05:15 2011 +0000
+++ b/model/ProvenanceModel.html	Tue Nov 29 09:38:10 2011 +0000
@@ -349,9 +349,9 @@
     <section id='section-time-event'> 
 <h4>Time and Event</h4>
 
-<p>Time is critical in the context of provenance, since it can help corroborate provenance claims. If an entity is claimed to be obtained by transforming another, then the latter must have existed before the former. If it is not the case, then there is something wrong in such a provenance claim. </p>
-
-<p> Time is critical, but we should also recognize that provenance can be used in many different contexts: in a single system, across the Web, or in spatial applications, to name a few. Hence, it is a design objective of PROV-DM to minimize the assumptions about time, so that PROV-DM can be used in varied contexts.  </p>
+<p>Time is critical in the context of provenance, since it can help corroborate provenance claims. For instance, if an entity is claimed to be obtained by transforming another, then the latter must have existed before the former. If it is not the case, then there is something wrong in such a provenance claim. </p>
+
+<p> Although time is critical, we should also recognize that provenance can be used in many different contexts: in a single system, across the Web, or in spatial data management, to name a few. Hence, it is a design objective of PROV-DM to minimize the assumptions about time, so that PROV-DM can be used in varied contexts.  </p>
 
 <p>Furthermore, consider two activities that started at the same time
 instant. Just by referring to that instant, we cannot distinguish
@@ -371,8 +371,8 @@
 <section>
 <h4>Types of Events</h4>
 
-<p>Four kinds of events underpin the PROV-DM data model. Those events are boundaries of intervals: duration interval of activities and characterization interval for entities. 
- They are defined as follows.
+<p>Four kinds of events underpin the PROV-DM data model. The <strong>activity start</strong> and <strong>activity end</strong>  events demarcate the beginning and the end of activities, respectively. The <strong>entity generation</strong> and <strong>entity usage</strong> events demarcate the characterization interval for entities. More specifically:
+
 </p>
 
 <p>An <dfn id="dfn-usage-event">entity generation event</dfn> is the <a>event</a> that marks the  final instant of an entity's creation timespan, after which it becomes available for use.</p>
@@ -396,8 +396,8 @@
 
 <p>Specifically, <dfn id="dfn-follows">follows</dfn> is a partial
 order between <a title="event">events</a>, indicating that an <a>event</a> occurs after another.
-For convenience, <dfn id="dfn-precedes">precedes</dfn> is defined as
-the symmetric of follows. </p>
+For symmetry, <dfn id="dfn-precedes">precedes</dfn> is defined as
+the inverse of follows. </p>
 
 
 <p> How such partial order is realized in practice is beyond the scope