(set-option :incremental false)
(set-info :status unsat)
(set-logic QF_UF)
(declare-sort U 0)
(declare-fun p (U U) Bool)
(declare-fun x () U)
(declare-fun y () U)
(assert (=> (p x y) (p y x)))
(assert (p x y))
(check-sat-assuming ( (not (p y x)) ))