--- a/model/working-copy/towards-wd4.html	Fri Feb 10 21:12:09 2012 +0000
+++ b/model/working-copy/towards-wd4.html	Mon Feb 13 08:53:59 2012 +0000
@@ -294,14 +294,16 @@
     <section id='conceptualization'> 
 <h1>Overview</h1>
 
-PROV-DM is a data model for describing the provenance of <em>Entities</em>, that is, of things in the world. The term "Things" encompasses a broad diversity of concepts, including digital objects such as a file or web page, physical things such as a building or a printed book, or a car as well as abstract concepts and ideas. One can regard any Web resource as an example of Entity in this context. This section provides an overview of the main elements of the PROV data model. 
+This section provides an overview of the main elements and relations of the PROV data model. 
+
 
   
     <section id='section-entity-activity-agent'> 
 <h2>Entity, Activity, Agent</h2>
 
 
-
+<p>PROV-DM is a data model for describing the provenance of <em>Entities</em>, that is, of things in the world. The term "Things" encompasses a broad diversity of concepts, including digital objects such as a file or web page, 
+physical things such as a building or a printed book, or a car as well as abstract concepts and ideas. One can regard any Web resource as an example of Entity in this context. </p>
 
 <p><dfn title="concept-entity">Entities</dfn> are things in the world one
  wants to provide provenance for.  For the purpose of this
@@ -310,22 +312,27 @@
 </p>
 
 
-<!--
 <div class="anexample" id="entity-example">
-An entity may be a web page at a URI, a file in a file system, a car or an idea.
+An entity may be the document at URI <a href="http://www.w3.org/TR/prov-dm/">http://www.w3.org/TR/prov-dm/</a>, a file in a file system, a car or an idea.
 </div>
--->
-
-<p>An <dfn title="concept-activity">Activity</dfn> is anything that can operate on entities. In particular, activities may produce, consume, or transform an entity. Activities that operate on digital entities may for example move, copy, or duplicate them.
+
+
+
+<p>An <dfn id="concept-activity">activity</dfn> is anything that involves
+entities; this involvement can take multiple forms:  consuming them,  processing them, 
+transforming them,  modifying them,  changing them,  relocating
+them,  using them,  generating them, being associated with them,
+etc. Activities that operate on digital entities may for example move, copy, or duplicate them.</p>
 
 
 
 <div class="anexample" id="activity-example">
-An activity may be the publishing of a document on the web, sending a tweet, extracting metadata embedded in a file, or driving a car from Boston to Cambridge, assembling a data set based on a set of measurements, performing a statistical analysis over a data set, sorting news items according to some criteria, running a sparql query over a triple store, and editing a file.
+<p>An activity may be the publishing of a document on the web, sending a twitter message, extracting metadata embedded in a file, or driving a car from Boston to Cambridge, assembling a data set based on a set of measurements, performing a statistical analysis over a data set, sorting news items according to some criteria, running a sparql query over a triple store, and editing a file.</p>
 </div>
 
-<p>An <dfn title="concept-agent">agent</dfn> is a type of entity that can be associated to an activity, to indicate that it bears some form of responsibility for the activity taking
-place.
+
+<p>An <dfn id="concept-agent">agent</dfn> is a type of entity that takes an active role in an activity such that it can be assigned some degree of responsibility for the activity taking.</p>
+
 
 <p>The key purpose of agents is to assign responsibility
 for activities.