(defrule raunt
(person (name ?x) (gender female))
(person (name ?q))
(person (name ?y))
(parent (parentname ?q) (childname ?x))
(parent (parentname ?q) (childname ?y))
(parent (parentname ?y) (childname ?z))
=>
(if (<> (str-compare ?x ?y) 0) then
(printout t ?x “ is an aunt of “ ?z crlf)
(assert (aunt (name1 ?x) (name2 ?z))))
)