0.11/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.11/0.13 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.13/0.34 % Computer : n027.cluster.edu 0.13/0.34 % Model : x86_64 x86_64 0.13/0.34 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.13/0.34 % Memory : 8042.1875MB 0.13/0.34 % OS : Linux 3.10.0-693.el7.x86_64 0.13/0.34 % CPULimit : 180 0.13/0.34 % DateTime : Thu Aug 29 09:45:09 EDT 2019 0.13/0.34 % CPUTime : 0.54/0.71 % SZS status Unsatisfiable 0.54/0.71 0.54/0.71 % SZS output start Proof 0.54/0.71 Take the following subset of the input axioms: 0.54/0.71 fof(associativity, axiom, ![X, Y, Z]: multiply(multiply(X, Y), Z)=multiply(X, multiply(Y, Z))). 0.54/0.71 fof(associativity_of_lub, axiom, ![X, Y, Z]: least_upper_bound(X, least_upper_bound(Y, Z))=least_upper_bound(least_upper_bound(X, Y), Z)). 0.54/0.71 fof(idempotence_of_lub, axiom, ![X]: least_upper_bound(X, X)=X). 0.54/0.71 fof(left_identity, axiom, ![X]: X=multiply(identity, X)). 0.54/0.71 fof(left_inverse, axiom, ![X]: multiply(inverse(X), X)=identity). 0.54/0.71 fof(lub_absorbtion, axiom, ![X, Y]: X=least_upper_bound(X, greatest_lower_bound(X, Y))). 0.54/0.71 fof(monotony_lub1, axiom, ![X, Y, Z]: least_upper_bound(multiply(X, Y), multiply(X, Z))=multiply(X, least_upper_bound(Y, Z))). 0.54/0.71 fof(monotony_lub2, axiom, ![X, Y, Z]: least_upper_bound(multiply(Y, X), multiply(Z, X))=multiply(least_upper_bound(Y, Z), X)). 0.54/0.71 fof(p39d_1, hypothesis, b=greatest_lower_bound(a, b)). 0.54/0.71 fof(prove_p39d, negated_conjecture, inverse(b)!=least_upper_bound(inverse(a), inverse(b))). 0.54/0.71 fof(symmetry_of_glb, axiom, ![X, Y]: greatest_lower_bound(Y, X)=greatest_lower_bound(X, Y)). 0.54/0.71 fof(symmetry_of_lub, axiom, ![X, Y]: least_upper_bound(X, Y)=least_upper_bound(Y, X)). 0.54/0.71 0.54/0.71 Now clausify the problem and encode Horn clauses using encoding 3 of 0.54/0.71 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.54/0.71 We repeatedly replace C & s=t => u=v by the two clauses: 0.54/0.71 fresh(y, y, x1...xn) = u 0.54/0.71 C => fresh(s, t, x1...xn) = v 0.54/0.71 where fresh is a fresh function symbol and x1..xn are the free 0.54/0.71 variables of u and v. 0.54/0.71 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.54/0.71 input problem has no model of domain size 1). 0.54/0.71 0.54/0.71 The encoding turns the above axioms into the following unit equations and goals: 0.54/0.71 0.54/0.71 Axiom 1 (left_inverse): multiply(inverse(X), X) = identity. 0.54/0.71 Axiom 2 (associativity): multiply(multiply(X, Y), Z) = multiply(X, multiply(Y, Z)). 0.54/0.71 Axiom 3 (left_identity): X = multiply(identity, X). 0.54/0.71 Axiom 4 (symmetry_of_lub): least_upper_bound(X, Y) = least_upper_bound(Y, X). 0.54/0.71 Axiom 5 (lub_absorbtion): X = least_upper_bound(X, greatest_lower_bound(X, Y)). 0.54/0.71 Axiom 6 (symmetry_of_glb): greatest_lower_bound(X, Y) = greatest_lower_bound(Y, X). 0.54/0.71 Axiom 7 (idempotence_of_lub): least_upper_bound(X, X) = X. 0.54/0.71 Axiom 8 (monotony_lub2): least_upper_bound(multiply(X, Y), multiply(Z, Y)) = multiply(least_upper_bound(X, Z), Y). 0.54/0.71 Axiom 9 (monotony_lub1): least_upper_bound(multiply(X, Y), multiply(X, Z)) = multiply(X, least_upper_bound(Y, Z)). 0.54/0.71 Axiom 10 (associativity_of_lub): least_upper_bound(X, least_upper_bound(Y, Z)) = least_upper_bound(least_upper_bound(X, Y), Z). 0.54/0.71 Axiom 11 (p39d_1): b = greatest_lower_bound(a, b). 0.54/0.71 0.54/0.71 Lemma 12: multiply(inverse(X), multiply(X, Y)) = Y. 0.54/0.71 Proof: 0.54/0.71 multiply(inverse(X), multiply(X, Y)) 0.54/0.71 = { by axiom 2 (associativity) } 0.54/0.71 multiply(multiply(inverse(X), X), Y) 0.54/0.71 = { by axiom 1 (left_inverse) } 0.54/0.71 multiply(identity, Y) 0.54/0.71 = { by axiom 3 (left_identity) } 0.54/0.71 Y 0.54/0.71 0.54/0.71 Lemma 13: multiply(inverse(inverse(X)), identity) = X. 0.54/0.71 Proof: 0.54/0.71 multiply(inverse(inverse(X)), identity) 0.54/0.71 = { by axiom 1 (left_inverse) } 0.54/0.71 multiply(inverse(inverse(X)), multiply(inverse(X), X)) 0.54/0.71 = { by lemma 12 } 0.54/0.71 X 0.54/0.71 0.54/0.71 Lemma 14: multiply(X, identity) = X. 0.54/0.71 Proof: 0.54/0.71 multiply(X, identity) 0.54/0.71 = { by lemma 12 } 0.54/0.71 multiply(inverse(inverse(X)), multiply(inverse(X), multiply(X, identity))) 0.54/0.71 = { by lemma 12 } 0.54/0.71 multiply(inverse(inverse(X)), identity) 0.54/0.71 = { by lemma 13 } 0.54/0.71 X 0.54/0.71 0.54/0.71 Goal 1 (prove_p39d): inverse(b) = least_upper_bound(inverse(a), inverse(b)). 0.54/0.71 Proof: 0.54/0.71 inverse(b) 0.54/0.71 = { by axiom 3 (left_identity) } 0.54/0.71 multiply(identity, inverse(b)) 0.54/0.71 = { by axiom 1 (left_inverse) } 0.54/0.71 multiply(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), least_upper_bound(inverse(inverse(b)), a)), inverse(b)) 0.54/0.71 = { by axiom 7 (idempotence_of_lub) } 0.54/0.71 multiply(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), least_upper_bound(least_upper_bound(inverse(inverse(b)), inverse(inverse(b))), a)), inverse(b)) 0.54/0.71 = { by axiom 10 (associativity_of_lub) } 0.54/0.71 multiply(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), least_upper_bound(inverse(inverse(b)), least_upper_bound(inverse(inverse(b)), a))), inverse(b)) 0.54/0.71 = { by axiom 4 (symmetry_of_lub) } 0.54/0.71 multiply(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), least_upper_bound(least_upper_bound(inverse(inverse(b)), a), inverse(inverse(b)))), inverse(b)) 0.54/0.71 = { by axiom 9 (monotony_lub1) } 0.54/0.71 multiply(least_upper_bound(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), least_upper_bound(inverse(inverse(b)), a)), multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), inverse(inverse(b)))), inverse(b)) 0.54/0.71 = { by axiom 1 (left_inverse) } 0.54/0.71 multiply(least_upper_bound(identity, multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), inverse(inverse(b)))), inverse(b)) 0.54/0.71 = { by axiom 4 (symmetry_of_lub) } 0.54/0.71 multiply(least_upper_bound(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), inverse(inverse(b))), identity), inverse(b)) 0.54/0.71 = { by axiom 8 (monotony_lub2) } 0.54/0.71 least_upper_bound(multiply(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), inverse(inverse(b))), inverse(b)), multiply(identity, inverse(b))) 0.54/0.71 = { by axiom 2 (associativity) } 0.54/0.71 least_upper_bound(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), multiply(inverse(inverse(b)), inverse(b))), multiply(identity, inverse(b))) 0.54/0.71 = { by axiom 1 (left_inverse) } 0.54/0.71 least_upper_bound(multiply(inverse(least_upper_bound(inverse(inverse(b)), a)), identity), multiply(identity, inverse(b))) 0.54/0.71 = { by lemma 14 } 0.54/0.71 least_upper_bound(inverse(least_upper_bound(inverse(inverse(b)), a)), multiply(identity, inverse(b))) 0.54/0.71 = { by axiom 3 (left_identity) } 0.54/0.71 least_upper_bound(inverse(least_upper_bound(inverse(inverse(b)), a)), inverse(b)) 0.54/0.71 = { by axiom 4 (symmetry_of_lub) } 0.54/0.71 least_upper_bound(inverse(b), inverse(least_upper_bound(inverse(inverse(b)), a))) 0.54/0.71 = { by axiom 4 (symmetry_of_lub) } 0.54/0.71 least_upper_bound(inverse(b), inverse(least_upper_bound(a, inverse(inverse(b))))) 0.54/0.71 = { by lemma 14 } 0.54/0.71 least_upper_bound(inverse(b), inverse(least_upper_bound(a, multiply(inverse(inverse(b)), identity)))) 0.54/0.71 = { by lemma 13 } 0.54/0.71 least_upper_bound(inverse(b), inverse(least_upper_bound(a, b))) 0.54/0.71 = { by axiom 11 (p39d_1) } 0.54/0.71 least_upper_bound(inverse(b), inverse(least_upper_bound(a, greatest_lower_bound(a, b)))) 0.54/0.71 = { by axiom 5 (lub_absorbtion) } 0.54/0.71 least_upper_bound(inverse(b), inverse(a)) 0.54/0.71 = { by axiom 4 (symmetry_of_lub) } 0.54/0.71 least_upper_bound(inverse(a), inverse(b)) 0.54/0.71 % SZS output end Proof 0.54/0.71 0.54/0.71 RESULT: Unsatisfiable (the axioms are contradictory). 0.54/0.72 EOF