--- a/model/prov-constraints.html	Mon Jul 23 10:04:16 2012 +0100
+++ b/model/prov-constraints.html	Mon Jul 23 10:18:03 2012 +0100
@@ -1531,7 +1531,7 @@
 <p><span class='conditional'>IF</span> <span
   class="name">wasDerivedFrom(id;e2,e1,_act,_gen,_use,attrs)</span>
   holds, <span class='conditional'>THEN</span> <span
-  class="name">wasDerivedFrom(id;e2,e1,attrs)</span> holds.
+  class="name">wasDerivedFrom(id;e2,e1,-,-,-,attrs)</span> holds.
 </p>
 </div>
 
@@ -3070,6 +3070,16 @@
   </div>
 
 
+   <hr />
+   <p id='membership-empty-collection_text'> An empty colleciton cannot contain any member, expressed by
+  the following constraint:
+  </p>
+  <div class='constraint' id='membership-empty-collection'>
+<p> <span class="conditional">IF</span> <span  class="name">entity(c,[prov:type='prov:EmptyCollection'])</span> and <span  class="name">entity(e,_attrs)</span>  and <span
+   class="name">hasMember(c,e)</span> <span class="conditional">THEN</span> <span class="conditional">INVALID</span>.</p>
+  </div>
+
+
 </section> <!--impossibility-constraints -->
 
 </section> <!-- constraints -->