Approved BLD Test Case demonstrating class membership. This test cases defines a rule that represents an "isFatherOf" relation between male family members. It uses RIF class memberships to test if a family member is of the class "Male". Note that is not an example of Core syntax because of the membership facts. Class_Membership-premise.rif http://www.w3.org/2005/rules/test/repository/tc/Class_Membership/Class_Membership-premise.rif ) Group ( Forall ?X ?Y ( fam:isFatherOf(?Y ?X) :- And (fam:isChildOf(?X ?Y) ?Y#fam:Male ) ) fam:isChildOf(fam:Adrian fam:Uwe) fam:Adrian#fam:Male fam:Uwe#fam:Male ) ) ]]> Class_Membership-conclusion.rif http://www.w3.org/2005/rules/test/repository/tc/Class_Membership/Class_Membership-conclusion.rif