0.10/0.11 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.10/0.12 % Command : parallel-twee %s --tstp --conditional-encoding if --smaller --drop-non-horn --give-up-on-saturation --explain-encoding --formal-proof 0.12/0.33 % Computer : n003.cluster.edu 0.12/0.33 % Model : x86_64 x86_64 0.12/0.33 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.12/0.33 % Memory : 8042.1875MB 0.12/0.33 % OS : Linux 3.10.0-693.el7.x86_64 0.12/0.33 % CPULimit : 1200 0.12/0.33 % WCLimit : 120 0.12/0.33 % DateTime : Tue Jul 13 13:19:54 EDT 2021 0.12/0.33 % CPUTime : 0.18/0.41 % SZS status Unsatisfiable 0.18/0.41 0.18/0.41 % SZS output start Proof 0.18/0.41 Axiom 1 (l_definition): apply(X, apply(Y, Y)) = apply(apply(l, X), Y). 0.18/0.41 Axiom 2 (s_definition): apply(apply(apply(s, X), Y), Z) = apply(apply(X, Z), apply(Y, Z)). 0.18/0.41 0.18/0.41 Goal 1 (prove_fixed_point): apply(X, f(X)) = apply(f(X), apply(X, f(X))). 0.18/0.41 The goal is true when: 0.18/0.41 X = apply(apply(s, l), l) 0.18/0.41 0.18/0.41 Proof: 0.18/0.41 apply(apply(apply(s, l), l), f(apply(apply(s, l), l))) 0.18/0.41 = { by axiom 2 (s_definition) } 0.18/0.41 apply(apply(l, f(apply(apply(s, l), l))), apply(l, f(apply(apply(s, l), l)))) 0.18/0.41 = { by axiom 1 (l_definition) R->L } 0.18/0.41 apply(f(apply(apply(s, l), l)), apply(apply(l, f(apply(apply(s, l), l))), apply(l, f(apply(apply(s, l), l))))) 0.18/0.41 = { by axiom 2 (s_definition) R->L } 0.18/0.41 apply(f(apply(apply(s, l), l)), apply(apply(apply(s, l), l), f(apply(apply(s, l), l)))) 0.18/0.41 % SZS output end Proof 0.18/0.41 0.18/0.41 RESULT: Unsatisfiable (the axioms are contradictory). 0.18/0.42 EOF