0.03/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.03/0.12 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.12/0.33 % Computer : n018.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 11:21:51 EDT 2019 0.12/0.33 % CPUTime : 0.19/0.46 % SZS status Unsatisfiable 0.19/0.46 0.19/0.46 % SZS output start Proof 0.19/0.46 Take the following subset of the input axioms: 0.19/0.46 fof(c01, axiom, ![A, B]: B=mult(A, ld(A, B))). 0.19/0.46 fof(c02, axiom, ![A, B]: B=ld(A, mult(A, B))). 0.19/0.46 fof(c05, axiom, ![A]: A=mult(A, unit)). 0.19/0.46 fof(c07, axiom, ![A, B, C]: mult(mult(A, mult(A, B)), C)=mult(mult(A, A), mult(B, C))). 0.19/0.46 fof(goals, negated_conjecture, mult(mult(a, mult(b, b)), c)!=mult(a, mult(b, mult(b, c)))). 0.19/0.46 0.19/0.46 Now clausify the problem and encode Horn clauses using encoding 3 of 0.19/0.46 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.19/0.46 We repeatedly replace C & s=t => u=v by the two clauses: 0.19/0.46 fresh(y, y, x1...xn) = u 0.19/0.46 C => fresh(s, t, x1...xn) = v 0.19/0.46 where fresh is a fresh function symbol and x1..xn are the free 0.19/0.46 variables of u and v. 0.19/0.46 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.19/0.46 input problem has no model of domain size 1). 0.19/0.46 0.19/0.46 The encoding turns the above axioms into the following unit equations and goals: 0.19/0.46 0.19/0.46 Axiom 1 (c02): X = ld(Y, mult(Y, X)). 0.19/0.46 Axiom 2 (c01): X = mult(Y, ld(Y, X)). 0.19/0.46 Axiom 3 (c07): mult(mult(X, mult(X, Y)), Z) = mult(mult(X, X), mult(Y, Z)). 0.19/0.46 Axiom 4 (c05): X = mult(X, unit). 0.19/0.46 0.19/0.46 Lemma 5: mult(X, mult(X, mult(ld(X, Y), Z))) = mult(mult(X, Y), Z). 0.19/0.46 Proof: 0.19/0.46 mult(X, mult(X, mult(ld(X, Y), Z))) 0.19/0.46 = { by axiom 4 (c05) } 0.19/0.46 mult(mult(X, mult(X, mult(ld(X, Y), Z))), unit) 0.19/0.46 = { by axiom 3 (c07) } 0.19/0.46 mult(mult(X, X), mult(mult(ld(X, Y), Z), unit)) 0.19/0.46 = { by axiom 4 (c05) } 0.19/0.46 mult(mult(X, X), mult(ld(X, Y), Z)) 0.19/0.46 = { by axiom 3 (c07) } 0.19/0.46 mult(mult(X, mult(X, ld(X, Y))), Z) 0.19/0.46 = { by axiom 2 (c01) } 0.19/0.46 mult(mult(X, Y), Z) 0.19/0.46 0.19/0.46 Lemma 6: mult(X, mult(ld(X, unit), Y)) = Y. 0.19/0.46 Proof: 0.19/0.46 mult(X, mult(ld(X, unit), Y)) 0.19/0.46 = { by axiom 1 (c02) } 0.19/0.46 ld(X, mult(X, mult(X, mult(ld(X, unit), Y)))) 0.19/0.46 = { by lemma 5 } 0.19/0.46 ld(X, mult(mult(X, unit), Y)) 0.19/0.46 = { by axiom 4 (c05) } 0.19/0.46 ld(X, mult(X, Y)) 0.19/0.46 = { by axiom 1 (c02) } 0.19/0.46 Y 0.19/0.46 0.19/0.46 Lemma 7: ld(ld(X, unit), Y) = mult(X, Y). 0.19/0.46 Proof: 0.19/0.46 ld(ld(X, unit), Y) 0.19/0.46 = { by lemma 6 } 0.19/0.46 mult(X, mult(ld(X, unit), ld(ld(X, unit), Y))) 0.19/0.46 = { by axiom 2 (c01) } 0.19/0.46 mult(X, Y) 0.19/0.46 0.19/0.46 Lemma 8: ld(ld(X, ld(X, Y)), Z) = ld(Y, mult(X, mult(X, Z))). 0.19/0.46 Proof: 0.19/0.46 ld(ld(X, ld(X, Y)), Z) 0.19/0.46 = { by axiom 1 (c02) } 0.19/0.46 ld(mult(X, ld(X, Y)), mult(mult(X, ld(X, Y)), ld(ld(X, ld(X, Y)), Z))) 0.19/0.46 = { by axiom 2 (c01) } 0.19/0.46 ld(Y, mult(mult(X, ld(X, Y)), ld(ld(X, ld(X, Y)), Z))) 0.19/0.46 = { by lemma 5 } 0.19/0.46 ld(Y, mult(X, mult(X, mult(ld(X, ld(X, Y)), ld(ld(X, ld(X, Y)), Z))))) 0.19/0.46 = { by axiom 2 (c01) } 0.19/0.46 ld(Y, mult(X, mult(X, Z))) 0.19/0.46 0.19/0.46 Goal 1 (goals): mult(mult(a, mult(b, b)), c) = mult(a, mult(b, mult(b, c))). 0.19/0.46 Proof: 0.19/0.46 mult(mult(a, mult(b, b)), c) 0.19/0.46 = { by lemma 7 } 0.19/0.46 mult(ld(ld(a, unit), mult(b, b)), c) 0.19/0.46 = { by axiom 4 (c05) } 0.19/0.46 mult(ld(ld(a, unit), mult(b, mult(b, unit))), c) 0.19/0.46 = { by lemma 8 } 0.19/0.46 mult(ld(ld(b, ld(b, ld(a, unit))), unit), c) 0.19/0.46 = { by axiom 1 (c02) } 0.19/0.46 ld(ld(b, ld(b, ld(a, unit))), mult(ld(b, ld(b, ld(a, unit))), mult(ld(ld(b, ld(b, ld(a, unit))), unit), c))) 0.19/0.46 = { by lemma 6 } 0.19/0.46 ld(ld(b, ld(b, ld(a, unit))), c) 0.19/0.46 = { by lemma 8 } 0.19/0.46 ld(ld(a, unit), mult(b, mult(b, c))) 0.19/0.46 = { by lemma 7 } 0.19/0.46 mult(a, mult(b, mult(b, c))) 0.19/0.46 % SZS output end Proof 0.19/0.46 0.19/0.46 RESULT: Unsatisfiable (the axioms are contradictory). 0.19/0.46 EOF