; EXPECT: unsat
(set-option :incremental false)
(set-logic ALL)
(set-option :sets-ext true)
(declare-sort Atom 0)
(declare-fun x () (Set (Tuple Atom Atom)))
(declare-fun y () (Set (Tuple Atom Atom)))
(declare-fun r () (Set (Tuple Atom Atom)))
(declare-fun t () (Set (Tuple Atom)))
(declare-fun a () Atom)
(declare-fun b () Atom)
(declare-fun c () Atom)
(declare-fun d () Atom)
(declare-fun e () Atom)
(assert (set.member (tuple a) (rel.join_image x 2)))
(assert (= x (set.union (set.union (set.singleton (tuple b c)) (set.singleton (tuple d e))) (set.singleton (tuple c e)))))
(assert (not (= a b)))
(check-sat)