; @author Sarah Winkler ; @cops 1136 ; secret problem 2019 ; category: INF (format CTRS semi-equational :problem infeasibility) (fun a 0) (fun b 0) (fun f 2) (rule (f (f x y) (f z w)) (f (f x z) (f y w))) (rule (f (f x y) x) x) (infeasible? (= (f b a) (f a b)))