0.07/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.07/0.12 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.12/0.33 % Computer : n013.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 : 180 0.12/0.33 % DateTime : Thu Aug 29 09:27:31 EDT 2019 0.12/0.34 % CPUTime : 0.12/0.35 % SZS status Unsatisfiable 0.12/0.35 0.12/0.35 % SZS output start Proof 0.12/0.35 Take the following subset of the input axioms: 0.12/0.35 fof(prove_these_axioms_1, negated_conjecture, multiply(inverse(a1), a1)!=multiply(inverse(b1), b1)). 0.12/0.35 fof(single_axiom, axiom, ![A, B, C]: multiply(multiply(multiply(A, B), C), inverse(multiply(A, C)))=B). 0.12/0.35 0.12/0.35 Now clausify the problem and encode Horn clauses using encoding 3 of 0.12/0.35 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.12/0.35 We repeatedly replace C & s=t => u=v by the two clauses: 0.12/0.35 fresh(y, y, x1...xn) = u 0.12/0.35 C => fresh(s, t, x1...xn) = v 0.12/0.35 where fresh is a fresh function symbol and x1..xn are the free 0.12/0.35 variables of u and v. 0.12/0.35 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.12/0.35 input problem has no model of domain size 1). 0.12/0.35 0.12/0.35 The encoding turns the above axioms into the following unit equations and goals: 0.12/0.35 0.12/0.35 Axiom 1 (single_axiom): multiply(multiply(multiply(X, Y), Z), inverse(multiply(X, Z))) = Y. 0.12/0.35 0.12/0.35 Lemma 2: multiply(Y, inverse(multiply(multiply(Z, Y), inverse(multiply(Z, X))))) = X. 0.12/0.35 Proof: 0.12/0.35 multiply(Y, inverse(multiply(multiply(Z, Y), inverse(multiply(Z, X))))) 0.12/0.35 = { by axiom 1 (single_axiom) } 0.12/0.35 multiply(multiply(multiply(multiply(Z, Y), X), inverse(multiply(Z, X))), inverse(multiply(multiply(Z, Y), inverse(multiply(Z, X))))) 0.12/0.35 = { by axiom 1 (single_axiom) } 0.12/0.35 X 0.12/0.35 0.12/0.35 Lemma 3: multiply(X, multiply(multiply(?, ?), inverse(multiply(?, ?)))) = X. 0.12/0.35 Proof: 0.12/0.35 multiply(X, multiply(multiply(?, ?), inverse(multiply(?, ?)))) 0.12/0.35 = { by lemma 2 } 0.12/0.35 multiply(X, multiply(multiply(multiply(?, inverse(multiply(multiply(?, ?), inverse(multiply(?, ?))))), ?), inverse(multiply(?, ?)))) 0.12/0.35 = { by axiom 1 (single_axiom) } 0.12/0.35 multiply(X, inverse(multiply(multiply(?, ?), inverse(multiply(?, ?))))) 0.12/0.35 = { by lemma 2 } 0.12/0.35 multiply(X, inverse(multiply(multiply(multiply(?, inverse(multiply(multiply(?, ?), inverse(multiply(?, ?))))), ?), inverse(multiply(?, ?))))) 0.12/0.35 = { by axiom 1 (single_axiom) } 0.12/0.35 multiply(X, inverse(inverse(multiply(multiply(?, ?), inverse(multiply(?, ?)))))) 0.12/0.35 = { by axiom 1 (single_axiom) } 0.12/0.35 multiply(X, inverse(multiply(multiply(multiply(?, inverse(multiply(multiply(?, ?), inverse(multiply(?, ?))))), X), inverse(multiply(?, X))))) 0.12/0.35 = { by lemma 2 } 0.12/0.35 multiply(X, inverse(multiply(multiply(?, X), inverse(multiply(?, X))))) 0.12/0.35 = { by lemma 2 } 0.12/0.35 X 0.12/0.35 0.12/0.35 Lemma 4: multiply(multiply(Y, X), inverse(Y)) = X. 0.12/0.35 Proof: 0.12/0.35 multiply(multiply(Y, X), inverse(Y)) 0.12/0.35 = { by lemma 3 } 0.12/0.35 multiply(multiply(multiply(Y, X), multiply(multiply(?, ?), inverse(multiply(?, ?)))), inverse(Y)) 0.12/0.35 = { by lemma 3 } 0.12/0.35 multiply(multiply(multiply(Y, X), multiply(multiply(?, ?), inverse(multiply(?, ?)))), inverse(multiply(Y, multiply(multiply(?, ?), inverse(multiply(?, ?)))))) 0.12/0.35 = { by axiom 1 (single_axiom) } 0.12/0.36 X 0.12/0.36 0.12/0.36 Lemma 5: multiply(inverse(X), Y) = multiply(Y, inverse(X)). 0.12/0.36 Proof: 0.12/0.36 multiply(inverse(X), Y) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(multiply(X, multiply(inverse(X), Y)), inverse(X)) 0.12/0.36 = { by lemma 2 } 0.12/0.36 multiply(multiply(multiply(inverse(X), Y), inverse(multiply(multiply(X, multiply(inverse(X), Y)), inverse(multiply(X, multiply(X, multiply(inverse(X), Y))))))), inverse(X)) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(multiply(multiply(inverse(X), Y), inverse(multiply(multiply(multiply(X, multiply(X, multiply(inverse(X), Y))), inverse(X)), inverse(multiply(X, multiply(X, multiply(inverse(X), Y))))))), inverse(X)) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(multiply(multiply(inverse(X), Y), inverse(inverse(X))), inverse(X)) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(Y, inverse(X)) 0.12/0.36 0.12/0.36 Lemma 6: multiply(X, inverse(multiply(Y, inverse(Y)))) = X. 0.12/0.36 Proof: 0.12/0.36 multiply(X, inverse(multiply(Y, inverse(Y)))) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(multiply(multiply(Y, X), inverse(Y)), inverse(multiply(Y, inverse(Y)))) 0.12/0.36 = { by axiom 1 (single_axiom) } 0.12/0.36 X 0.12/0.36 0.12/0.36 Lemma 7: multiply(Y, inverse(Y)) = multiply(?, inverse(?)). 0.12/0.36 Proof: 0.12/0.36 multiply(Y, inverse(Y)) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(Y, inverse(multiply(multiply(Z, Y), inverse(Z)))) 0.12/0.36 = { by lemma 6 } 0.12/0.36 multiply(Y, inverse(multiply(multiply(Z, Y), inverse(multiply(Z, inverse(multiply(X, inverse(X)))))))) 0.12/0.36 = { by lemma 2 } 0.12/0.36 inverse(multiply(X, inverse(X))) 0.12/0.36 = { by lemma 2 } 0.12/0.36 multiply(?, inverse(multiply(multiply(Z, ?), inverse(multiply(Z, inverse(multiply(X, inverse(X)))))))) 0.12/0.36 = { by lemma 6 } 0.12/0.36 multiply(?, inverse(multiply(multiply(Z, ?), inverse(Z)))) 0.12/0.36 = { by lemma 4 } 0.12/0.36 multiply(?, inverse(?)) 0.12/0.36 0.12/0.36 Goal 1 (prove_these_axioms_1): multiply(inverse(a1), a1) = multiply(inverse(b1), b1). 0.12/0.36 Proof: 0.12/0.36 multiply(inverse(a1), a1) 0.12/0.36 = { by lemma 5 } 0.12/0.36 multiply(a1, inverse(a1)) 0.12/0.36 = { by lemma 7 } 0.12/0.36 multiply(?, inverse(?)) 0.12/0.36 = { by lemma 7 } 0.12/0.36 multiply(b1, inverse(b1)) 0.12/0.36 = { by lemma 5 } 0.12/0.36 multiply(inverse(b1), b1) 0.12/0.36 % SZS output end Proof 0.12/0.36 0.12/0.36 RESULT: Unsatisfiable (the axioms are contradictory). 0.12/0.36 EOF