0.10/0.11 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.10/0.11 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.11/0.32 % Computer : n009.cluster.edu 0.11/0.32 % Model : x86_64 x86_64 0.11/0.32 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.11/0.32 % Memory : 8042.1875MB 0.11/0.32 % OS : Linux 3.10.0-693.el7.x86_64 0.11/0.32 % CPULimit : 180 0.11/0.32 % DateTime : Thu Aug 29 09:58:27 EDT 2019 0.11/0.32 % CPUTime : 0.11/0.34 % SZS status Unsatisfiable 0.11/0.34 0.11/0.34 % SZS output start Proof 0.11/0.34 Take the following subset of the input axioms: 0.11/0.34 fof(multiply, axiom, ![A, B]: divide(A, inverse(B))=multiply(A, B)). 0.11/0.34 fof(prove_these_axioms_4, negated_conjecture, multiply(b, a)!=multiply(a, b)). 0.11/0.34 fof(single_axiom, axiom, ![A, B, C]: divide(divide(divide(A, inverse(B)), C), divide(A, C))=B). 0.11/0.34 0.11/0.34 Now clausify the problem and encode Horn clauses using encoding 3 of 0.11/0.34 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.11/0.34 We repeatedly replace C & s=t => u=v by the two clauses: 0.11/0.34 fresh(y, y, x1...xn) = u 0.11/0.34 C => fresh(s, t, x1...xn) = v 0.11/0.34 where fresh is a fresh function symbol and x1..xn are the free 0.11/0.34 variables of u and v. 0.11/0.34 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.11/0.34 input problem has no model of domain size 1). 0.11/0.34 0.11/0.34 The encoding turns the above axioms into the following unit equations and goals: 0.11/0.34 0.11/0.34 Axiom 1 (single_axiom): divide(divide(divide(X, inverse(Y)), Z), divide(X, Z)) = Y. 0.11/0.34 Axiom 2 (multiply): divide(X, inverse(Y)) = multiply(X, Y). 0.11/0.34 0.11/0.34 Lemma 3: divide(divide(multiply(Y, X), Z), divide(Y, Z)) = X. 0.11/0.34 Proof: 0.11/0.34 divide(divide(multiply(Y, X), Z), divide(Y, Z)) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(divide(Y, inverse(X)), Z), divide(Y, Z)) 0.11/0.34 = { by axiom 1 (single_axiom) } 0.11/0.34 X 0.11/0.34 0.11/0.34 Lemma 4: divide(multiply(multiply(Y, X), Z), multiply(Y, Z)) = X. 0.11/0.34 Proof: 0.11/0.34 divide(multiply(multiply(Y, X), Z), multiply(Y, Z)) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(multiply(divide(Y, inverse(X)), Z), multiply(Y, Z)) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(divide(Y, inverse(X)), inverse(Z)), multiply(Y, Z)) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(divide(Y, inverse(X)), inverse(Z)), divide(Y, inverse(Z))) 0.11/0.34 = { by axiom 1 (single_axiom) } 0.11/0.34 X 0.11/0.34 0.11/0.34 Lemma 5: divide(multiply(Y, X), Y) = X. 0.11/0.34 Proof: 0.11/0.34 divide(multiply(Y, X), Y) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(Y, inverse(X)), Y) 0.11/0.34 = { by axiom 1 (single_axiom) } 0.11/0.34 divide(divide(divide(divide(divide(multiply(multiply(?, inverse(X)), ?), inverse(Y)), multiply(?, ?)), divide(multiply(multiply(?, inverse(X)), ?), multiply(?, ?))), inverse(X)), Y) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(divide(divide(multiply(multiply(multiply(?, inverse(X)), ?), Y), multiply(?, ?)), divide(multiply(multiply(?, inverse(X)), ?), multiply(?, ?))), inverse(X)), Y) 0.11/0.34 = { by lemma 4 } 0.11/0.34 divide(divide(divide(divide(multiply(multiply(multiply(?, inverse(X)), ?), Y), multiply(?, ?)), inverse(X)), inverse(X)), Y) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(multiply(divide(multiply(multiply(multiply(?, inverse(X)), ?), Y), multiply(?, ?)), X), inverse(X)), Y) 0.11/0.34 = { by axiom 2 (multiply) } 0.11/0.34 divide(divide(multiply(divide(divide(multiply(multiply(?, inverse(X)), ?), inverse(Y)), multiply(?, ?)), X), inverse(X)), Y) 0.11/0.34 = { by lemma 4 } 0.11/0.34 divide(divide(multiply(divide(divide(multiply(multiply(?, inverse(X)), ?), inverse(Y)), multiply(?, ?)), X), divide(multiply(multiply(?, inverse(X)), ?), multiply(?, ?))), Y) 0.11/0.34 = { by axiom 1 (single_axiom) } 0.11/0.34 divide(divide(multiply(divide(divide(multiply(multiply(?, inverse(X)), ?), inverse(Y)), multiply(?, ?)), X), divide(multiply(multiply(?, inverse(X)), ?), multiply(?, ?))), divide(divide(divide(multiply(multiply(?, inverse(X)), ?), inverse(Y)), multiply(?, ?)), divide(multiply(multiply(?, inverse(X)), ?), multiply(?, ?)))) 0.11/0.34 = { by lemma 3 } 0.11/0.35 X 0.11/0.35 0.11/0.35 Goal 1 (prove_these_axioms_4): multiply(b, a) = multiply(a, b). 0.11/0.35 Proof: 0.11/0.35 multiply(b, a) 0.11/0.35 = { by lemma 5 } 0.11/0.35 multiply(divide(multiply(a, b), a), a) 0.11/0.35 = { by axiom 2 (multiply) } 0.11/0.35 divide(divide(multiply(a, b), a), inverse(a)) 0.11/0.35 = { by lemma 3 } 0.11/0.35 divide(divide(divide(divide(multiply(inverse(a), multiply(a, b)), inverse(multiply(inverse(a), multiply(a, b)))), divide(inverse(a), inverse(multiply(inverse(a), multiply(a, b))))), a), inverse(a)) 0.11/0.35 = { by lemma 5 } 0.11/0.35 divide(divide(divide(divide(multiply(inverse(a), multiply(a, b)), inverse(multiply(inverse(a), multiply(a, b)))), divide(inverse(a), inverse(multiply(inverse(a), multiply(a, b))))), divide(multiply(multiply(inverse(a), multiply(inverse(a), multiply(a, b))), a), multiply(inverse(a), multiply(inverse(a), multiply(a, b))))), inverse(a)) 0.11/0.35 = { by axiom 2 (multiply) } 0.11/0.35 divide(divide(divide(divide(multiply(inverse(a), multiply(a, b)), inverse(multiply(inverse(a), multiply(a, b)))), divide(inverse(a), inverse(multiply(inverse(a), multiply(a, b))))), divide(divide(multiply(inverse(a), multiply(inverse(a), multiply(a, b))), inverse(a)), multiply(inverse(a), multiply(inverse(a), multiply(a, b))))), inverse(a)) 0.11/0.35 = { by lemma 5 } 0.11/0.35 divide(divide(divide(divide(multiply(inverse(a), multiply(a, b)), inverse(multiply(inverse(a), multiply(a, b)))), divide(inverse(a), inverse(multiply(inverse(a), multiply(a, b))))), divide(multiply(inverse(a), multiply(a, b)), multiply(inverse(a), multiply(inverse(a), multiply(a, b))))), inverse(a)) 0.11/0.35 = { by axiom 2 (multiply) } 0.11/0.35 divide(divide(divide(divide(multiply(inverse(a), multiply(a, b)), inverse(multiply(inverse(a), multiply(a, b)))), divide(inverse(a), inverse(multiply(inverse(a), multiply(a, b))))), divide(multiply(inverse(a), multiply(a, b)), divide(inverse(a), inverse(multiply(inverse(a), multiply(a, b)))))), inverse(a)) 0.11/0.35 = { by axiom 1 (single_axiom) } 0.11/0.35 divide(multiply(inverse(a), multiply(a, b)), inverse(a)) 0.11/0.35 = { by lemma 5 } 0.11/0.35 multiply(a, b) 0.11/0.35 % SZS output end Proof 0.11/0.35 0.11/0.35 RESULT: Unsatisfiable (the axioms are contradictory). 0.11/0.35 EOF