Hello all, how to denote this rule, which will be fulfilled when for every Integer(this>10) exists at least one Integer, where existing Integer's value is equal to -(this) For example: If in working memory are present only these facts: Integer(5) Integer(20) Integer(-20) then requested condition should be fulfilled because 5 is not above 10 -20 is not above 10 20 is above 10 and exists -20 where -20 =-(20) Peter -- View this message in context: http://drools.46999.n3.nabble.com/first-order-logic-for-every-fact-exists... Sent from the Drools: User forum mailing list archive at Nabble.com.