0.08/0.15 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.08/0.15 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.14/0.37 % Computer : n008.cluster.edu 0.14/0.37 % Model : x86_64 x86_64 0.14/0.37 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.14/0.37 % Memory : 8042.1875MB 0.14/0.37 % OS : Linux 3.10.0-693.el7.x86_64 0.14/0.37 % CPULimit : 180 0.14/0.37 % DateTime : Thu Aug 29 10:54:38 EDT 2019 0.14/0.37 % CPUTime : 0.21/0.44 % SZS status Unsatisfiable 0.21/0.44 0.21/0.44 % SZS output start Proof 0.21/0.44 Take the following subset of the input axioms: 0.21/0.44 fof(identity, axiom, ![A]: identity=double_divide(A, inverse(A))). 0.21/0.44 fof(inverse, axiom, ![A]: double_divide(A, identity)=inverse(A)). 0.21/0.44 fof(multiply, axiom, ![A, B]: double_divide(double_divide(B, A), identity)=multiply(A, B)). 0.21/0.44 fof(prove_these_axioms_3, negated_conjecture, multiply(a3, multiply(b3, c3))!=multiply(multiply(a3, b3), c3)). 0.21/0.44 fof(single_axiom, axiom, ![A, B, C]: double_divide(double_divide(A, double_divide(double_divide(B, double_divide(A, C)), double_divide(identity, C))), double_divide(identity, identity))=B). 0.21/0.44 0.21/0.44 Now clausify the problem and encode Horn clauses using encoding 3 of 0.21/0.44 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.21/0.44 We repeatedly replace C & s=t => u=v by the two clauses: 0.21/0.44 fresh(y, y, x1...xn) = u 0.21/0.44 C => fresh(s, t, x1...xn) = v 0.21/0.44 where fresh is a fresh function symbol and x1..xn are the free 0.21/0.44 variables of u and v. 0.21/0.44 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.21/0.44 input problem has no model of domain size 1). 0.21/0.44 0.21/0.44 The encoding turns the above axioms into the following unit equations and goals: 0.21/0.44 0.21/0.44 Axiom 1 (multiply): double_divide(double_divide(X, Y), identity) = multiply(Y, X). 0.21/0.44 Axiom 2 (single_axiom): double_divide(double_divide(X, double_divide(double_divide(Y, double_divide(X, Z)), double_divide(identity, Z))), double_divide(identity, identity)) = Y. 0.21/0.44 Axiom 3 (inverse): double_divide(X, identity) = inverse(X). 0.21/0.44 Axiom 4 (identity): identity = double_divide(X, inverse(X)). 0.21/0.44 0.21/0.44 Lemma 5: double_divide(double_divide(Y, double_divide(double_divide(X, inverse(Y)), inverse(identity))), inverse(identity)) = X. 0.21/0.44 Proof: 0.21/0.44 double_divide(double_divide(Y, double_divide(double_divide(X, inverse(Y)), inverse(identity))), inverse(identity)) 0.21/0.44 = { by axiom 3 (inverse) } 0.21/0.44 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(Y, identity)), inverse(identity))), inverse(identity)) 0.21/0.44 = { by axiom 3 (inverse) } 0.21/0.44 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(Y, identity)), double_divide(identity, identity))), inverse(identity)) 0.21/0.44 = { by axiom 3 (inverse) } 0.21/0.44 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(Y, identity)), double_divide(identity, identity))), double_divide(identity, identity)) 0.21/0.44 = { by axiom 2 (single_axiom) } 0.21/0.44 X 0.21/0.44 0.21/0.44 Lemma 6: double_divide(inverse(X), inverse(identity)) = X. 0.21/0.44 Proof: 0.21/0.44 double_divide(inverse(X), inverse(identity)) 0.21/0.44 = { by axiom 3 (inverse) } 0.21/0.44 double_divide(double_divide(X, identity), inverse(identity)) 0.21/0.44 = { by axiom 4 (identity) } 0.21/0.45 double_divide(double_divide(X, double_divide(identity, inverse(identity))), inverse(identity)) 0.21/0.45 = { by axiom 4 (identity) } 0.21/0.45 double_divide(double_divide(X, double_divide(double_divide(X, inverse(X)), inverse(identity))), inverse(identity)) 0.21/0.45 = { by lemma 5 } 0.21/0.45 X 0.21/0.45 0.21/0.45 Lemma 7: inverse(inverse(X)) = multiply(identity, X). 0.21/0.45 Proof: 0.21/0.45 inverse(inverse(X)) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 double_divide(inverse(X), identity) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 double_divide(double_divide(X, identity), identity) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 multiply(identity, X) 0.21/0.45 0.21/0.45 Lemma 8: double_divide(multiply(identity, X), inverse(identity)) = inverse(X). 0.21/0.45 Proof: 0.21/0.45 double_divide(multiply(identity, X), inverse(identity)) 0.21/0.45 = { by lemma 7 } 0.21/0.45 double_divide(inverse(inverse(X)), inverse(identity)) 0.21/0.45 = { by lemma 6 } 0.21/0.45 inverse(X) 0.21/0.45 0.21/0.45 Lemma 9: double_divide(double_divide(identity, X), inverse(identity)) = multiply(identity, X). 0.21/0.45 Proof: 0.21/0.45 double_divide(double_divide(identity, X), inverse(identity)) 0.21/0.45 = { by lemma 6 } 0.21/0.45 double_divide(double_divide(identity, double_divide(inverse(X), inverse(identity))), inverse(identity)) 0.21/0.45 = { by lemma 8 } 0.21/0.45 double_divide(double_divide(identity, double_divide(double_divide(multiply(identity, X), inverse(identity)), inverse(identity))), inverse(identity)) 0.21/0.45 = { by lemma 5 } 0.21/0.45 multiply(identity, X) 0.21/0.45 0.21/0.45 Lemma 10: multiply(identity, identity) = identity. 0.21/0.45 Proof: 0.21/0.45 multiply(identity, identity) 0.21/0.45 = { by lemma 9 } 0.21/0.45 double_divide(double_divide(identity, identity), inverse(identity)) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 double_divide(inverse(identity), inverse(identity)) 0.21/0.45 = { by lemma 6 } 0.21/0.45 identity 0.21/0.45 0.21/0.45 Lemma 11: multiply(identity, double_divide(X, Y)) = inverse(multiply(Y, X)). 0.21/0.45 Proof: 0.21/0.45 multiply(identity, double_divide(X, Y)) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 double_divide(double_divide(double_divide(X, Y), identity), identity) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 double_divide(multiply(Y, X), identity) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 inverse(multiply(Y, X)) 0.21/0.45 0.21/0.45 Lemma 12: inverse(double_divide(X, Y)) = multiply(Y, X). 0.21/0.45 Proof: 0.21/0.45 inverse(double_divide(X, Y)) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 double_divide(double_divide(X, Y), identity) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 multiply(Y, X) 0.21/0.45 0.21/0.45 Lemma 13: inverse(identity) = identity. 0.21/0.45 Proof: 0.21/0.45 inverse(identity) 0.21/0.45 = { by lemma 8 } 0.21/0.45 double_divide(multiply(identity, identity), inverse(identity)) 0.21/0.45 = { by lemma 10 } 0.21/0.45 double_divide(identity, inverse(identity)) 0.21/0.45 = { by axiom 4 (identity) } 0.21/0.45 identity 0.21/0.45 0.21/0.45 Lemma 14: multiply(identity, X) = X. 0.21/0.45 Proof: 0.21/0.45 multiply(identity, X) 0.21/0.45 = { by lemma 7 } 0.21/0.45 inverse(inverse(X)) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 double_divide(inverse(X), identity) 0.21/0.45 = { by lemma 13 } 0.21/0.45 double_divide(inverse(X), inverse(identity)) 0.21/0.45 = { by lemma 6 } 0.21/0.45 X 0.21/0.45 0.21/0.45 Lemma 15: double_divide(identity, X) = inverse(X). 0.21/0.45 Proof: 0.21/0.45 double_divide(identity, X) 0.21/0.45 = { by lemma 5 } 0.21/0.45 double_divide(double_divide(identity, double_divide(double_divide(double_divide(identity, X), inverse(identity)), inverse(identity))), inverse(identity)) 0.21/0.45 = { by lemma 9 } 0.21/0.45 double_divide(double_divide(identity, double_divide(multiply(identity, X), inverse(identity))), inverse(identity)) 0.21/0.45 = { by lemma 9 } 0.21/0.45 multiply(identity, double_divide(multiply(identity, X), inverse(identity))) 0.21/0.45 = { by lemma 11 } 0.21/0.45 inverse(multiply(inverse(identity), multiply(identity, X))) 0.21/0.45 = { by lemma 12 } 0.21/0.45 inverse(multiply(inverse(identity), inverse(double_divide(X, identity)))) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 inverse(double_divide(double_divide(inverse(double_divide(X, identity)), inverse(identity)), identity)) 0.21/0.45 = { by lemma 6 } 0.21/0.45 inverse(double_divide(double_divide(X, identity), identity)) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 inverse(inverse(double_divide(X, identity))) 0.21/0.45 = { by lemma 12 } 0.21/0.45 inverse(multiply(identity, X)) 0.21/0.45 = { by lemma 7 } 0.21/0.45 inverse(inverse(inverse(X))) 0.21/0.45 = { by lemma 7 } 0.21/0.45 multiply(identity, inverse(X)) 0.21/0.45 = { by lemma 14 } 0.21/0.45 inverse(X) 0.21/0.45 0.21/0.45 Lemma 16: multiply(multiply(Y, X), inverse(Y)) = X. 0.21/0.45 Proof: 0.21/0.45 multiply(multiply(Y, X), inverse(Y)) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 multiply(double_divide(double_divide(X, Y), identity), inverse(Y)) 0.21/0.45 = { by lemma 10 } 0.21/0.45 multiply(double_divide(double_divide(X, Y), multiply(identity, identity)), inverse(Y)) 0.21/0.45 = { by axiom 1 (multiply) } 0.21/0.45 double_divide(double_divide(inverse(Y), double_divide(double_divide(X, Y), multiply(identity, identity))), identity) 0.21/0.45 = { by lemma 6 } 0.21/0.45 double_divide(double_divide(inverse(Y), double_divide(double_divide(X, double_divide(inverse(Y), inverse(identity))), multiply(identity, identity))), identity) 0.21/0.45 = { by lemma 7 } 0.21/0.45 double_divide(double_divide(inverse(Y), double_divide(double_divide(X, double_divide(inverse(Y), inverse(identity))), inverse(inverse(identity)))), identity) 0.21/0.45 = { by lemma 15 } 0.21/0.45 double_divide(double_divide(inverse(Y), double_divide(double_divide(X, double_divide(inverse(Y), inverse(identity))), double_divide(identity, inverse(identity)))), identity) 0.21/0.45 = { by lemma 13 } 0.21/0.45 double_divide(double_divide(inverse(Y), double_divide(double_divide(X, double_divide(inverse(Y), inverse(identity))), double_divide(identity, inverse(identity)))), inverse(identity)) 0.21/0.45 = { by lemma 15 } 0.21/0.45 double_divide(double_divide(inverse(Y), double_divide(double_divide(X, double_divide(inverse(Y), inverse(identity))), double_divide(identity, inverse(identity)))), double_divide(identity, identity)) 0.21/0.45 = { by axiom 2 (single_axiom) } 0.21/0.45 X 0.21/0.45 0.21/0.45 Lemma 17: double_divide(multiply(Y, X), inverse(identity)) = double_divide(X, Y). 0.21/0.45 Proof: 0.21/0.45 double_divide(multiply(Y, X), inverse(identity)) 0.21/0.45 = { by lemma 12 } 0.21/0.45 double_divide(inverse(double_divide(X, Y)), inverse(identity)) 0.21/0.45 = { by lemma 6 } 0.21/0.45 double_divide(X, Y) 0.21/0.45 0.21/0.45 Lemma 18: multiply(Y, double_divide(Y, X)) = inverse(X). 0.21/0.45 Proof: 0.21/0.45 multiply(Y, double_divide(Y, X)) 0.21/0.45 = { by lemma 16 } 0.21/0.45 multiply(multiply(multiply(X, Y), inverse(X)), double_divide(Y, X)) 0.21/0.45 = { by lemma 17 } 0.21/0.45 multiply(multiply(multiply(X, Y), inverse(X)), double_divide(multiply(X, Y), inverse(identity))) 0.21/0.45 = { by lemma 13 } 0.21/0.45 multiply(multiply(multiply(X, Y), inverse(X)), double_divide(multiply(X, Y), identity)) 0.21/0.45 = { by axiom 3 (inverse) } 0.21/0.45 multiply(multiply(multiply(X, Y), inverse(X)), inverse(multiply(X, Y))) 0.21/0.45 = { by lemma 16 } 0.21/0.46 inverse(X) 0.21/0.46 0.21/0.46 Lemma 19: double_divide(X, Y) = double_divide(Y, X). 0.21/0.46 Proof: 0.21/0.46 double_divide(X, Y) 0.21/0.46 = { by lemma 16 } 0.21/0.46 multiply(multiply(X, double_divide(X, Y)), inverse(X)) 0.21/0.46 = { by lemma 18 } 0.21/0.46 multiply(inverse(Y), inverse(X)) 0.21/0.46 = { by axiom 3 (inverse) } 0.21/0.46 multiply(double_divide(Y, identity), inverse(X)) 0.21/0.46 = { by axiom 1 (multiply) } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(Y, identity)), identity) 0.21/0.46 = { by axiom 2 (single_axiom) } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(double_divide(identity, double_divide(double_divide(Y, double_divide(identity, inverse(X))), double_divide(identity, inverse(X)))), double_divide(identity, identity)), identity)), identity) 0.21/0.46 = { by lemma 15 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(inverse(double_divide(double_divide(Y, double_divide(identity, inverse(X))), double_divide(identity, inverse(X)))), double_divide(identity, identity)), identity)), identity) 0.21/0.46 = { by lemma 12 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(multiply(double_divide(identity, inverse(X)), double_divide(Y, double_divide(identity, inverse(X)))), double_divide(identity, identity)), identity)), identity) 0.21/0.46 = { by lemma 15 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(multiply(double_divide(identity, inverse(X)), double_divide(Y, double_divide(identity, inverse(X)))), inverse(identity)), identity)), identity) 0.21/0.46 = { by lemma 17 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(double_divide(Y, double_divide(identity, inverse(X))), double_divide(identity, inverse(X))), identity)), identity) 0.21/0.46 = { by lemma 15 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(double_divide(Y, inverse(inverse(X))), double_divide(identity, inverse(X))), identity)), identity) 0.21/0.46 = { by lemma 15 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(double_divide(Y, inverse(inverse(X))), inverse(inverse(X))), identity)), identity) 0.21/0.46 = { by lemma 13 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(double_divide(Y, inverse(inverse(X))), inverse(inverse(X))), inverse(identity))), identity) 0.21/0.46 = { by lemma 13 } 0.21/0.46 double_divide(double_divide(inverse(X), double_divide(double_divide(double_divide(Y, inverse(inverse(X))), inverse(inverse(X))), inverse(identity))), inverse(identity)) 0.21/0.46 = { by lemma 5 } 0.21/0.46 double_divide(Y, inverse(inverse(X))) 0.21/0.46 = { by lemma 7 } 0.21/0.46 double_divide(Y, multiply(identity, X)) 0.21/0.46 = { by lemma 14 } 0.21/0.46 double_divide(Y, X) 0.21/0.46 0.21/0.46 Lemma 20: multiply(X, Y) = multiply(Y, X). 0.21/0.46 Proof: 0.21/0.46 multiply(X, Y) 0.21/0.46 = { by axiom 1 (multiply) } 0.21/0.46 double_divide(double_divide(Y, X), identity) 0.21/0.46 = { by lemma 19 } 0.21/0.46 double_divide(double_divide(X, Y), identity) 0.21/0.46 = { by axiom 1 (multiply) } 0.21/0.46 multiply(Y, X) 0.21/0.46 0.21/0.46 Lemma 21: double_divide(inverse(X), inverse(Y)) = multiply(X, Y). 0.21/0.46 Proof: 0.21/0.46 double_divide(inverse(X), inverse(Y)) 0.21/0.46 = { by lemma 18 } 0.21/0.46 double_divide(inverse(X), multiply(X, double_divide(X, Y))) 0.21/0.46 = { by lemma 17 } 0.21/0.46 double_divide(multiply(multiply(X, double_divide(X, Y)), inverse(X)), inverse(identity)) 0.21/0.46 = { by lemma 16 } 0.21/0.46 double_divide(double_divide(X, Y), inverse(identity)) 0.21/0.46 = { by lemma 13 } 0.21/0.46 double_divide(double_divide(X, Y), identity) 0.21/0.46 = { by axiom 3 (inverse) } 0.21/0.46 inverse(double_divide(X, Y)) 0.21/0.46 = { by lemma 12 } 0.21/0.46 multiply(Y, X) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(X, Y) 0.21/0.46 0.21/0.46 Lemma 22: multiply(X, inverse(Y)) = double_divide(Y, inverse(X)). 0.21/0.46 Proof: 0.21/0.46 multiply(X, inverse(Y)) 0.21/0.46 = { by lemma 21 } 0.21/0.46 double_divide(inverse(X), inverse(inverse(Y))) 0.21/0.46 = { by lemma 7 } 0.21/0.46 double_divide(inverse(X), multiply(identity, Y)) 0.21/0.46 = { by lemma 14 } 0.21/0.46 double_divide(inverse(X), Y) 0.21/0.46 = { by lemma 19 } 0.21/0.46 double_divide(Y, inverse(X)) 0.21/0.46 0.21/0.46 Lemma 23: double_divide(double_divide(Y, Z), inverse(X)) = multiply(X, multiply(Y, Z)). 0.21/0.46 Proof: 0.21/0.46 double_divide(double_divide(Y, Z), inverse(X)) 0.21/0.46 = { by lemma 19 } 0.21/0.46 double_divide(inverse(X), double_divide(Y, Z)) 0.21/0.46 = { by lemma 19 } 0.21/0.46 double_divide(double_divide(Y, Z), inverse(X)) 0.21/0.46 = { by lemma 22 } 0.21/0.46 multiply(X, inverse(double_divide(Y, Z))) 0.21/0.46 = { by lemma 15 } 0.21/0.46 multiply(X, double_divide(identity, double_divide(Y, Z))) 0.21/0.46 = { by lemma 16 } 0.21/0.46 multiply(multiply(multiply(identity, double_divide(Y, Z)), multiply(X, double_divide(identity, double_divide(Y, Z)))), inverse(multiply(identity, double_divide(Y, Z)))) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(multiply(multiply(double_divide(Y, Z), identity), multiply(X, double_divide(identity, double_divide(Y, Z)))), inverse(multiply(identity, double_divide(Y, Z)))) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(multiply(multiply(double_divide(Y, Z), identity), multiply(double_divide(identity, double_divide(Y, Z)), X)), inverse(multiply(identity, double_divide(Y, Z)))) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(multiply(multiply(double_divide(identity, double_divide(Y, Z)), X), multiply(double_divide(Y, Z), identity)), inverse(multiply(identity, double_divide(Y, Z)))) 0.21/0.46 = { by lemma 12 } 0.21/0.46 multiply(multiply(multiply(double_divide(identity, double_divide(Y, Z)), X), inverse(double_divide(identity, double_divide(Y, Z)))), inverse(multiply(identity, double_divide(Y, Z)))) 0.21/0.46 = { by lemma 16 } 0.21/0.46 multiply(X, inverse(multiply(identity, double_divide(Y, Z)))) 0.21/0.46 = { by lemma 22 } 0.21/0.46 double_divide(multiply(identity, double_divide(Y, Z)), inverse(X)) 0.21/0.46 = { by lemma 19 } 0.21/0.46 double_divide(inverse(X), multiply(identity, double_divide(Y, Z))) 0.21/0.46 = { by lemma 11 } 0.21/0.46 double_divide(inverse(X), inverse(multiply(Z, Y))) 0.21/0.46 = { by lemma 21 } 0.21/0.46 multiply(X, multiply(Z, Y)) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(X, multiply(Y, Z)) 0.21/0.46 0.21/0.46 Lemma 24: multiply(Y, multiply(double_divide(Y, Z), multiply(X, Z))) = X. 0.21/0.46 Proof: 0.21/0.46 multiply(Y, multiply(double_divide(Y, Z), multiply(X, Z))) 0.21/0.46 = { by lemma 23 } 0.21/0.46 multiply(Y, double_divide(double_divide(X, Z), inverse(double_divide(Y, Z)))) 0.21/0.46 = { by lemma 14 } 0.21/0.46 multiply(identity, multiply(Y, double_divide(double_divide(X, Z), inverse(double_divide(Y, Z))))) 0.21/0.46 = { by lemma 23 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, Z), inverse(double_divide(Y, Z)))), inverse(identity)) 0.21/0.46 = { by lemma 6 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(inverse(Z), inverse(identity))), inverse(double_divide(Y, Z)))), inverse(identity)) 0.21/0.46 = { by lemma 18 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(multiply(Y, double_divide(Y, Z)), inverse(identity))), inverse(double_divide(Y, Z)))), inverse(identity)) 0.21/0.46 = { by lemma 17 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(double_divide(Y, Z), Y)), inverse(double_divide(Y, Z)))), inverse(identity)) 0.21/0.46 = { by lemma 19 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(Y, double_divide(Y, Z))), inverse(double_divide(Y, Z)))), inverse(identity)) 0.21/0.46 = { by lemma 15 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(Y, double_divide(Y, Z))), double_divide(identity, double_divide(Y, Z)))), inverse(identity)) 0.21/0.46 = { by lemma 15 } 0.21/0.46 double_divide(double_divide(Y, double_divide(double_divide(X, double_divide(Y, double_divide(Y, Z))), double_divide(identity, double_divide(Y, Z)))), double_divide(identity, identity)) 0.21/0.46 = { by axiom 2 (single_axiom) } 0.21/0.46 X 0.21/0.46 0.21/0.46 Goal 1 (prove_these_axioms_3): multiply(a3, multiply(b3, c3)) = multiply(multiply(a3, b3), c3). 0.21/0.46 Proof: 0.21/0.46 multiply(a3, multiply(b3, c3)) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(a3, multiply(c3, b3)) 0.21/0.46 = { by lemma 24 } 0.21/0.46 multiply(a3, multiply(c3, multiply(double_divide(c3, multiply(b3, a3)), multiply(double_divide(double_divide(c3, multiply(b3, a3)), a3), multiply(b3, a3))))) 0.21/0.46 = { by lemma 24 } 0.21/0.46 multiply(a3, double_divide(double_divide(c3, multiply(b3, a3)), a3)) 0.21/0.46 = { by lemma 19 } 0.21/0.46 multiply(a3, double_divide(a3, double_divide(c3, multiply(b3, a3)))) 0.21/0.46 = { by lemma 20 } 0.21/0.46 multiply(a3, double_divide(a3, double_divide(c3, multiply(a3, b3)))) 0.21/0.46 = { by lemma 18 } 0.21/0.46 inverse(double_divide(c3, multiply(a3, b3))) 0.21/0.46 = { by lemma 12 } 0.21/0.46 multiply(multiply(a3, b3), c3) 0.21/0.46 % SZS output end Proof 0.21/0.46 0.21/0.46 RESULT: Unsatisfiable (the axioms are contradictory). 0.21/0.46 EOF