--- a/model/ProvenanceModel.html	Wed Nov 30 14:26:02 2011 +0000
+++ b/model/ProvenanceModel.html	Wed Nov 30 14:59:12 2011 +0000
@@ -1667,7 +1667,7 @@
 <li><em>activity</em>: an identifier <span class="name">a</span> of an activity record, which is a representation of the activity using and generating the above entities;</li>
 <li><em>generation</em>: an identifier  <span class="name">g2</span> of the generation record pertaining to <span class="name">e2</span> and <span class="name">a</span>;</li> 
 <li><em>usage</em>: an identifier  <span class="name">u1</span> of the usage record pertaining to <span class="name">e1</span> and <span class="name">a</span>.</li> 
-<li><em>attributes</em>: a set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation, optionally including the attribute-value pair <span class="name">prov:steps="1"</span>.</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation, optionally including the attribute-value pair <span class="name">prov:steps="1"</span>.</li>
 </ul>
 <p>It is OPTIONAL to include  the attribute <span class="name">prov:steps</span> in a precise-1 derivation since the record already refers to the one and only one activity underpinning the derivation.</p>
 
@@ -1687,7 +1687,7 @@
 <li><em>id</em>:  an OPTIONAL identifier  <span class="name">id</span> identifying the derivation record;</li> 
 <li><em>generatedEntity</em>: the identifier <span class="name">e2</span> of  an entity record, which is a representation of the generated entity;</li>
 <li><em>usedEntity</em>: the identifier <span class="name">e1</span> of  an entity record, which is a representation of the used entity.</li>
-<li><em>attributes</em>: a set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation; it optionally includes the attribute-value pair <span class="name">prov:steps="n"</span>.</li>
+<li><em>attributes</em>: an OPTIONAL set of attribute-value pairs <span class="name">attrs</span> that describe the modalities of this derivation; it optionally includes the attribute-value pair <span class="name">prov:steps="n"</span>.</li>
 </ul>
 <p>It is OPTIONAL to include  the attribute <span class="name">prov:steps</span> in an imprecise-n derivation record. It defaults to <span class="name">prov:steps="n"</span>.</p> 
 
@@ -1716,8 +1716,9 @@
 <span class="nonterminal">gIdentifier</span>
 <span class="name">,</span>
 <span class="nonterminal">uIdentifier</span>
-<span class="name">,</span>
+<span class="optional"><span class="name">,</span>
 <span class="nonterminal">attribute-values</span>
+</span>
 <span class="name">)</span><br/>
 <span class="nonterminal">imprecise-1-derivationRecord</span>::=  
 <span class="name">wasDerivedFrom</span>
@@ -1737,8 +1738,9 @@
 <span class="nonterminal">eIdentifier</span>
 <span class="name">,</span>
 <span class="nonterminal">eIdentifier</span>
-<span class="name">,</span>
+<span class="optional"><span class="name">,</span>
 <span class="nonterminal">attribute-values</span>
+</span>
 <span class="name">)</span>
 </div>
 <div class="note">
@@ -2910,13 +2912,14 @@
 <div class='constraint' id='wasRevision'>
 Given two identifiers <span class="name">old</span> and <span class="name">new</span> identifying two entities, and an identifier <span class="name">ag</span> identifying an agent,
 <span class='conditional'>if</span> a record <span class="name">wasRevisionOf(new,old,ag)</span> is asserted, <span class='conditional'>then</span> 
-there exists an entity record identifier <span class="name">e</span> and attribute-values <span class="name">av</span>, such that the following records hold:
+there exists an entity record identifier <span class="name">e</span> and attribute-values <span class="name">eAttrs</span>, <span class="name">dAttrs</span>, such that the following records hold:
 <ul>
-<li> <span class="name">wasDerivedFrom(new,old)</span>;
-<li> <span class="name">entity(e,av)</span>;
+<li> <span class="name">wasDerivedFrom(new,old,dAttrs)</span>;
+<li> <span class="name">entity(e,eAttrs)</span>;
 <li> <span class="name">wasComplementOf(new,e)</span>;
 <li> <span class="name">wasComplementOf(old,e)</span>.
 </ul>
+Derivation may of the kind imprecise-1 or imprecise-n.
 </div>
 
 <p><span class="name">wasRevisionOf</span> is a strict sub-relation