0.06/0.11 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.06/0.12 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.11/0.33 % Computer : n018.cluster.edu 0.11/0.33 % Model : x86_64 x86_64 0.11/0.33 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.11/0.33 % Memory : 8042.1875MB 0.11/0.33 % OS : Linux 3.10.0-693.el7.x86_64 0.11/0.33 % CPULimit : 180 0.11/0.33 % DateTime : Thu Aug 29 13:11:21 EDT 2019 0.11/0.33 % CPUTime : 6.37/6.57 % SZS status Unsatisfiable 6.37/6.57 6.37/6.57 % SZS output start Proof 6.37/6.57 Take the following subset of the input axioms: 6.37/6.57 fof(b_definition, axiom, ![X, Y, Z]: apply(apply(apply(b, X), Y), Z)=apply(X, apply(Y, Z))). 6.37/6.57 fof(prove_v_combinator, negated_conjecture, ![X]: apply(apply(h(X), f(X)), g(X))!=apply(apply(apply(X, f(X)), g(X)), h(X))). 6.37/6.57 fof(t_definition, axiom, ![X, Y]: apply(Y, X)=apply(apply(t, X), Y)). 6.37/6.57 6.37/6.57 Now clausify the problem and encode Horn clauses using encoding 3 of 6.37/6.57 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 6.37/6.57 We repeatedly replace C & s=t => u=v by the two clauses: 6.37/6.57 fresh(y, y, x1...xn) = u 6.37/6.57 C => fresh(s, t, x1...xn) = v 6.37/6.57 where fresh is a fresh function symbol and x1..xn are the free 6.37/6.57 variables of u and v. 6.37/6.57 A predicate p(X) is encoded as p(X)=true (this is sound, because the 6.37/6.57 input problem has no model of domain size 1). 6.37/6.57 6.37/6.57 The encoding turns the above axioms into the following unit equations and goals: 6.37/6.57 6.37/6.57 Axiom 1 (b_definition): apply(apply(apply(b, X), Y), Z) = apply(X, apply(Y, Z)). 6.37/6.57 Axiom 2 (t_definition): apply(X, Y) = apply(apply(t, Y), X). 6.37/6.57 6.37/6.57 Goal 1 (prove_v_combinator): apply(apply(h(X), f(X)), g(X)) = apply(apply(apply(X, f(X)), g(X)), h(X)). 6.37/6.57 The goal is true when: 6.37/6.57 X = apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))) 6.37/6.57 6.37/6.57 Proof: 6.37/6.57 apply(apply(h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 2 (t_definition) } 6.37/6.57 apply(apply(t, g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), apply(h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(b, apply(t, g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(apply(apply(b, b), t), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 2 (t_definition) } 6.37/6.57 apply(apply(t, f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), apply(apply(apply(apply(b, b), t), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(b, apply(t, f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))), apply(apply(apply(b, b), t), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(apply(apply(b, b), t), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), apply(apply(apply(b, b), t), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(apply(b, apply(apply(apply(b, b), t), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))), apply(apply(b, b), t)), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(apply(apply(apply(b, b), apply(apply(b, b), t)), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), apply(apply(b, b), t)), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 2 (t_definition) } 6.37/6.57 apply(apply(apply(apply(t, apply(apply(b, b), t)), apply(apply(apply(b, b), apply(apply(b, b), t)), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t)))))), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 = { by axiom 1 (b_definition) } 6.37/6.57 apply(apply(apply(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))), f(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), g(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))), h(apply(apply(b, apply(t, apply(apply(b, b), t))), apply(apply(b, b), apply(apply(b, b), t))))) 6.37/6.57 % SZS output end Proof 6.37/6.57 6.37/6.57 RESULT: Unsatisfiable (the axioms are contradictory). 6.37/6.58 EOF