Are the two following statements not equivalent? forall($msg:Message() Message(this==$msg, sent==true, status!=State._INITIALIZED) ) not( Message(sent==false, status==State._INITIALIZED) ) My understanding is that they both ensure that there are no Message objects in WM with property 'sent' set to false and property 'status' set to State._INITIALIZED. In my situation, the 'forall' approach is working as expected, the 'not' approach fires once (when there are no Message objects in WM) and never again. Appreciate if anyone could shed light on this. -- View this message in context: http://drools.46999.n3.nabble.com/Not-and-forall-operator-behaviour-tp402... Sent from the Drools: User forum mailing list archive at Nabble.com. _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users