--- a/model/working-copy/towards-wd4.html	Fri Feb 10 07:54:00 2012 +0000
+++ b/model/working-copy/towards-wd4.html	Fri Feb 10 08:16:11 2012 +0000
@@ -312,6 +312,11 @@
 <p>An <dfn id="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>The key purpose of agents is to assign responsibility
+for activities. 
+The definition of agent intentionally stays away from using concepts such as enabling, causing, initiating, affecting, etc, because many entities also enable, cause, initiate, and affect in some way
+the activities.  So the notion of having some degree of responsibility is really what makes an agent.</p>
+
 
 <p>An agents is a particular type of Entity. This means that the model can be
  used to express provenance of the agents themselves.  </p>
@@ -345,12 +350,8 @@
 
 
 <p>Usage examples include a procedure beginning to consume a parameter, a service starting to read a value on a port, a program beginning to read a configuration
-file, or the point at which an ingredient, such as eggs, is being added in a baking activity. Usage may entirely consume an entity (e.g. eggs are not longer available after being added to
-the mix), or leave it as such, ready for further uses (e.g. a file on a file system can be read indefinitely).</p>
-
-    <div class="note"> PM The egg example may be confusing: one expects to have some construct to distinguish between use-and-consume and use-without-consuming. Consider replacing with:<br/>
-in general the same entity may be used multiple times, possibly by different activities
-    </div>
+file, or the point at which an ingredient, such as eggs, is being added in a baking activity. Usage may entirely consume an entity (e.g. eggs are no longer available after being added to
+the mix); alternatively, a same entity may be used multiple times, possibly by different activities (e.g. a file on a file system can be read indefinitely).</p>
 
     
 </div>
@@ -421,36 +422,23 @@
 </section>
 
     <section id="section-responsibility"> 
-<h2>Responsibility</h2>
+<h2>Activity Association and Responsibility Chain</h2>
 
   
 
 
-<p>The key purpose of agents is to assign responsibility
-for activities. 
-The definition of agent intentionally stays away from using concepts such as enabling, causing, initiating, affecting, etc, because many entities also enable, cause, initiate, and affect in some way
-the activities.  So the notion of having some degree of responsibility is really what makes an agent.</p>
-
-<p>It is important to reflect that there is a degree in
-the responsibility of agents, and that is a major reason for
+
+<p>It is important to reflect that there is a degree in the
+responsibility of agents, and that is a major reason for
 distinguishing among all the agents that have some association with an
 activity and determine which ones are really the originators of the
 entity.  For example, a programmer and a researcher could both be
 associated with running a workflow, but it may not matter what
 programmer clicked the button to start the workflow while it would
-matter a lot what researcher told the programmer to do so.  Another
-example: a student publishing a web page describing an academic
-department could result in both the student and the department being
-agents associated with the activity, and it may not matter what
-student published a web page but it matters a lot that the department
-told the student to put up the web page.  So there is some notion of
-responsibility that needs to be captured. </p>
-
-<div class="anexample" id="association-example">
-<p>Examples of association between an activity and agent include designing, participation, initiation and termination, timetabling or sponsoring. </p>
-</div>
-
-<div class="note">paragraph below to be moved above, where plans are first mentioned?</div>
+matter a lot what researcher told the programmer to do so.  So there
+is some notion of responsibility that needs to be captured. </p>
+
+
 <p>Provenance reflects activities that have occurred.  In some  
 cases, those activities reflect the execution of a plan that was  
 designed in advance to guide the execution.  PROV-DM allows attaching  
@@ -458,11 +446,33 @@
 happen.  The plan can be useful for various tasks, for example to  
 validate the execution as represented in the provenance record, to  
 manage expectation failures, or to provide explanations.</p>
-<p>While PROV-DM does not
-specify the representations of plans, it allows for activities to be
-associated with plans. </p>
+
+
+
+
+<p>An <dfn id="concept-activityAssociation">activity association</dfn> is a relation between an activity and an agent, indicating that the agent had an active role in the activity. It further allow an activity to be associated with a plan, which a set of
+actions or steps intended by the agent to achieve some goals in the context of this activity.</p>
+
+<div class="anexample" id="association-example">
+<p>Examples of association between an activity and agent include designing, participation, initiation and termination, timetabling or sponsoring. </p>
+</div>
+
+<p>An <dfn id="concept-responsibilityChain">responsibility chain</dfn> is a relation between two agents,
+indicating that a "subordinate" agent acted on behalf of a "responsible" agent, in the context of an activity.</p>
+
+
+
+<div class="anexample" id="responsibilityChain-example">
+<p>A student publishing a web page describing an academic
+department could result in both the student and the department being
+agents associated with the activity, and it may not matter what
+student published a web page but it matters a lot that the department
+told the student to put up the web page.  
+</p>
+</div>
 </section>
 
+
     <section id="section-UML"> 
 <h2>Overview Diagram</h2>