0.06/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.06/0.12 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.13/0.33 % Computer : n010.cluster.edu 0.13/0.33 % Model : x86_64 x86_64 0.13/0.33 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.13/0.33 % Memory : 8042.1875MB 0.13/0.33 % OS : Linux 3.10.0-693.el7.x86_64 0.13/0.33 % CPULimit : 180 0.13/0.33 % DateTime : Thu Aug 29 13:10:51 EDT 2019 0.13/0.33 % CPUTime : 38.46/38.63 % SZS status Unsatisfiable 38.46/38.63 38.46/38.63 % SZS output start Proof 38.46/38.63 Take the following subset of the input axioms: 38.46/38.65 fof(absorption1, axiom, ![X, Y]: X=meet(X, join(X, Y))). 38.46/38.65 fof(absorption2, axiom, ![X, Y]: X=join(X, meet(X, Y))). 38.46/38.65 fof(associativity_of_join, axiom, ![X, Y, Z]: join(join(X, Y), Z)=join(X, join(Y, Z))). 38.46/38.65 fof(associativity_of_meet, axiom, ![X, Y, Z]: meet(X, meet(Y, Z))=meet(meet(X, Y), Z)). 38.46/38.65 fof(commutativity_of_join, axiom, ![X, Y]: join(X, Y)=join(Y, X)). 38.46/38.65 fof(commutativity_of_meet, axiom, ![X, Y]: meet(X, Y)=meet(Y, X)). 38.46/38.65 fof(complement_join, axiom, ![X]: one=join(X, complement(X))). 38.46/38.65 fof(complement_meet, axiom, ![X]: meet(X, complement(X))=zero). 38.46/38.65 fof(equation_H18, axiom, ![X, Y, Z]: join(meet(X, Y), meet(X, Z))=meet(X, join(meet(X, Y), join(meet(X, Z), meet(Y, join(X, Z)))))). 38.46/38.65 fof(idempotence_of_join, axiom, ![X]: X=join(X, X)). 38.46/38.65 fof(ifeq_axiom, axiom, ![A, B, C]: ifeq(A, A, B, C)=B). 38.46/38.65 fof(meet_join_complement, axiom, ![X, Y]: ifeq(join(X, Y), one, ifeq(meet(X, Y), zero, complement(X), Y), Y)=Y). 38.46/38.65 fof(prove_distributivity, negated_conjecture, complement(a)!=join(complement(b), complement(a))). 38.46/38.65 fof(prove_distributivity_hypothesis, hypothesis, meet(b, a)=a). 38.46/38.65 38.46/38.65 Now clausify the problem and encode Horn clauses using encoding 3 of 38.46/38.65 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 38.46/38.65 We repeatedly replace C & s=t => u=v by the two clauses: 38.46/38.65 fresh(y, y, x1...xn) = u 38.46/38.65 C => fresh(s, t, x1...xn) = v 38.46/38.65 where fresh is a fresh function symbol and x1..xn are the free 38.46/38.65 variables of u and v. 38.46/38.65 A predicate p(X) is encoded as p(X)=true (this is sound, because the 38.46/38.65 input problem has no model of domain size 1). 38.46/38.65 38.46/38.65 The encoding turns the above axioms into the following unit equations and goals: 38.46/38.65 38.46/38.65 Axiom 1 (meet_join_complement): ifeq(join(X, Y), one, ifeq(meet(X, Y), zero, complement(X), Y), Y) = Y. 38.46/38.65 Axiom 2 (prove_distributivity_hypothesis): meet(b, a) = a. 38.46/38.65 Axiom 3 (absorption1): X = meet(X, join(X, Y)). 38.46/38.65 Axiom 4 (associativity_of_join): join(join(X, Y), Z) = join(X, join(Y, Z)). 38.46/38.65 Axiom 5 (commutativity_of_meet): meet(X, Y) = meet(Y, X). 38.46/38.65 Axiom 6 (commutativity_of_join): join(X, Y) = join(Y, X). 38.46/38.65 Axiom 7 (ifeq_axiom): ifeq(X, X, Y, Z) = Y. 38.46/38.65 Axiom 8 (equation_H18): join(meet(X, Y), meet(X, Z)) = meet(X, join(meet(X, Y), join(meet(X, Z), meet(Y, join(X, Z))))). 38.46/38.65 Axiom 9 (idempotence_of_join): X = join(X, X). 38.46/38.65 Axiom 10 (absorption2): X = join(X, meet(X, Y)). 38.46/38.65 Axiom 11 (complement_join): one = join(X, complement(X)). 38.46/38.65 Axiom 12 (associativity_of_meet): meet(X, meet(Y, Z)) = meet(meet(X, Y), Z). 38.54/38.76 Axiom 13 (complement_meet): meet(X, complement(X)) = zero. 38.54/38.76 38.54/38.76 Lemma 14: ifeq(join(Y, X), one, ifeq(meet(X, Y), zero, complement(Y), X), X) = X. 38.54/38.76 Proof: 38.54/38.76 ifeq(join(Y, X), one, ifeq(meet(X, Y), zero, complement(Y), X), X) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 ifeq(join(Y, X), one, ifeq(meet(Y, X), zero, complement(Y), X), X) 38.54/38.76 = { by axiom 1 (meet_join_complement) } 38.54/38.76 X 38.54/38.76 38.54/38.76 Lemma 15: complement(complement(X)) = X. 38.54/38.76 Proof: 38.54/38.76 complement(complement(X)) 38.54/38.76 = { by axiom 7 (ifeq_axiom) } 38.54/38.76 ifeq(one, one, complement(complement(X)), X) 38.54/38.76 = { by axiom 11 (complement_join) } 38.54/38.76 ifeq(join(X, complement(X)), one, complement(complement(X)), X) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 ifeq(join(complement(X), X), one, complement(complement(X)), X) 38.54/38.76 = { by axiom 7 (ifeq_axiom) } 38.54/38.76 ifeq(join(complement(X), X), one, ifeq(zero, zero, complement(complement(X)), X), X) 38.54/38.76 = { by axiom 13 (complement_meet) } 38.54/38.76 ifeq(join(complement(X), X), one, ifeq(meet(X, complement(X)), zero, complement(complement(X)), X), X) 38.54/38.76 = { by lemma 14 } 38.54/38.76 X 38.54/38.76 38.54/38.76 Lemma 16: join(X, join(Z, meet(X, Y))) = join(X, Z). 38.54/38.76 Proof: 38.54/38.76 join(X, join(Z, meet(X, Y))) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 join(X, join(meet(X, Y), Z)) 38.54/38.76 = { by axiom 4 (associativity_of_join) } 38.54/38.76 join(join(X, meet(X, Y)), Z) 38.54/38.76 = { by axiom 10 (absorption2) } 38.54/38.76 join(X, Z) 38.54/38.76 38.54/38.76 Lemma 17: meet(X, join(Y, X)) = X. 38.54/38.76 Proof: 38.54/38.76 meet(X, join(Y, X)) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 meet(X, join(X, Y)) 38.54/38.76 = { by axiom 3 (absorption1) } 38.54/38.76 X 38.54/38.76 38.54/38.76 Lemma 18: meet(join(X, Y), join(X, meet(Y, Z))) = join(X, meet(Y, Z)). 38.54/38.76 Proof: 38.54/38.76 meet(join(X, Y), join(X, meet(Y, Z))) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 meet(join(Y, X), join(X, meet(Y, Z))) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 meet(join(X, meet(Y, Z)), join(Y, X)) 38.54/38.76 = { by lemma 16 } 38.54/38.76 meet(join(X, meet(Y, Z)), join(Y, join(X, meet(Y, Z)))) 38.54/38.76 = { by lemma 17 } 38.54/38.76 join(X, meet(Y, Z)) 38.54/38.76 38.54/38.76 Lemma 19: meet(b, join(a, meet(X, b))) = join(a, meet(X, b)). 38.54/38.76 Proof: 38.54/38.76 meet(b, join(a, meet(X, b))) 38.54/38.76 = { by axiom 10 (absorption2) } 38.54/38.76 meet(join(b, meet(b, a)), join(a, meet(X, b))) 38.54/38.76 = { by axiom 2 (prove_distributivity_hypothesis) } 38.54/38.76 meet(join(b, a), join(a, meet(X, b))) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 meet(join(a, b), join(a, meet(X, b))) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 meet(join(a, b), join(a, meet(b, X))) 38.54/38.76 = { by lemma 18 } 38.54/38.76 join(a, meet(b, X)) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 join(a, meet(X, b)) 38.54/38.76 38.54/38.76 Lemma 20: meet(X, one) = X. 38.54/38.76 Proof: 38.54/38.76 meet(X, one) 38.54/38.76 = { by axiom 11 (complement_join) } 38.54/38.76 meet(X, join(X, complement(X))) 38.54/38.76 = { by axiom 3 (absorption1) } 38.54/38.76 X 38.54/38.76 38.54/38.76 Lemma 21: join(X, one) = one. 38.54/38.76 Proof: 38.54/38.76 join(X, one) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 join(one, X) 38.54/38.76 = { by lemma 20 } 38.54/38.76 meet(join(one, X), one) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 meet(one, join(one, X)) 38.54/38.76 = { by axiom 3 (absorption1) } 38.54/38.76 one 38.54/38.76 38.54/38.76 Lemma 22: join(zero, X) = X. 38.54/38.76 Proof: 38.54/38.76 join(zero, X) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 join(X, zero) 38.54/38.76 = { by axiom 13 (complement_meet) } 38.54/38.76 join(X, meet(X, complement(X))) 38.54/38.76 = { by axiom 10 (absorption2) } 38.54/38.76 X 38.54/38.76 38.54/38.76 Lemma 23: complement(zero) = one. 38.54/38.76 Proof: 38.54/38.76 complement(zero) 38.54/38.76 = { by lemma 22 } 38.54/38.76 join(zero, complement(zero)) 38.54/38.76 = { by axiom 11 (complement_join) } 38.54/38.76 one 38.54/38.76 38.54/38.76 Lemma 24: meet(X, meet(Y, Z)) = meet(Z, meet(X, Y)). 38.54/38.76 Proof: 38.54/38.76 meet(X, meet(Y, Z)) 38.54/38.76 = { by axiom 12 (associativity_of_meet) } 38.54/38.76 meet(meet(X, Y), Z) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 meet(Z, meet(X, Y)) 38.54/38.76 38.54/38.76 Lemma 25: meet(X, meet(join(X, Y), Z)) = meet(X, Z). 38.54/38.76 Proof: 38.54/38.76 meet(X, meet(join(X, Y), Z)) 38.54/38.76 = { by lemma 24 } 38.54/38.76 meet(join(X, Y), meet(Z, X)) 38.54/38.76 = { by lemma 24 } 38.54/38.76 meet(Z, meet(X, join(X, Y))) 38.54/38.76 = { by axiom 3 (absorption1) } 38.54/38.76 meet(Z, X) 38.54/38.76 = { by axiom 5 (commutativity_of_meet) } 38.54/38.76 meet(X, Z) 38.54/38.76 38.54/38.76 Lemma 26: meet(X, meet(Y, join(Z, meet(X, Y)))) = meet(X, Y). 38.54/38.76 Proof: 38.54/38.76 meet(X, meet(Y, join(Z, meet(X, Y)))) 38.54/38.76 = { by axiom 6 (commutativity_of_join) } 38.54/38.76 meet(X, meet(Y, join(meet(X, Y), Z))) 38.54/38.76 = { by axiom 12 (associativity_of_meet) } 38.54/38.76 meet(meet(X, Y), join(meet(X, Y), Z)) 38.54/38.76 = { by axiom 3 (absorption1) } 38.68/38.87 meet(X, Y) 38.68/38.87 38.68/38.87 Lemma 27: join(meet(b, complement(a)), complement(join(a, meet(b, complement(a))))) = complement(a). 38.68/38.87 Proof: 38.68/38.87 join(meet(b, complement(a)), complement(join(a, meet(b, complement(a))))) 38.68/38.87 = { by axiom 1 (meet_join_complement) } 38.68/38.87 ifeq(join(a, join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), one, ifeq(meet(a, join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 4 (associativity_of_join) } 38.68/38.87 ifeq(join(join(a, meet(b, complement(a))), complement(join(a, meet(b, complement(a))))), one, ifeq(meet(a, join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 11 (complement_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(a, join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 15 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(meet(complement(a), b), complement(join(a, meet(b, complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(meet(complement(a), b), complement(join(a, meet(complement(a), b))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(a, meet(complement(a), b))), meet(complement(a), b))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(meet(complement(a), b), a)), meet(complement(a), b))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 15 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), b))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 26 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), meet(b, join(a, meet(complement(a), b)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 19 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(a, meet(complement(a), b))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(meet(complement(a), b), a)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 15 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(meet(complement(a), b), complement(complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(meet(complement(a), b), complement(complement(a))))), complement(complement(a))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 17 } 38.68/38.87 ifeq(one, one, ifeq(meet(join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(meet(complement(a), b), complement(complement(a))))), meet(complement(complement(a)), join(meet(complement(a), b), complement(complement(a))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 24 } 38.68/38.87 ifeq(one, one, ifeq(meet(join(meet(complement(a), b), complement(complement(a))), meet(join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(meet(complement(a), b), complement(complement(a))))), complement(complement(a)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 24 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(complement(a), join(meet(complement(a), b), complement(complement(a))))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(complement(join(meet(complement(a), b), complement(complement(a)))), meet(join(meet(complement(a), b), complement(complement(a))), complement(a))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), complement(join(meet(complement(a), b), complement(complement(a))))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 20 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), one)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 21 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(meet(complement(a), b), one))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(one, meet(complement(a), b)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 11 (complement_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(join(complement(a), complement(complement(a))), meet(complement(a), b)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 4 (associativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(complement(a), join(complement(complement(a)), meet(complement(a), b))))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(complement(a), join(meet(complement(a), b), complement(complement(a)))))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(join(meet(complement(a), b), complement(complement(a))), complement(a)))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 22 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(zero, join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(join(meet(complement(a), b), complement(complement(a))), complement(a))))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 13 (complement_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(join(meet(complement(a), b), complement(complement(a))))), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(a)), meet(complement(join(meet(complement(a), b), complement(complement(a)))), join(join(meet(complement(a), b), complement(complement(a))), complement(a))))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 8 (equation_H18) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(meet(join(meet(complement(a), b), complement(complement(a))), complement(join(meet(complement(a), b), complement(complement(a))))), meet(join(meet(complement(a), b), complement(complement(a))), complement(a)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 13 (complement_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), join(zero, meet(join(meet(complement(a), b), complement(complement(a))), complement(a)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 22 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(join(meet(complement(a), b), complement(complement(a))), complement(a))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(complement(a)), meet(complement(a), join(meet(complement(a), b), complement(complement(a))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 12 (associativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(meet(complement(complement(a)), complement(a)), join(meet(complement(a), b), complement(complement(a)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(meet(complement(a), complement(complement(a))), join(meet(complement(a), b), complement(complement(a)))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 12 (associativity_of_meet) } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(a), meet(complement(complement(a)), join(meet(complement(a), b), complement(complement(a))))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by lemma 17 } 38.68/38.87 ifeq(one, one, ifeq(meet(complement(a), complement(complement(a))), zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 13 (complement_meet) } 38.68/38.87 ifeq(one, one, ifeq(zero, zero, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 7 (ifeq_axiom) } 38.68/38.87 ifeq(one, one, complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.87 = { by axiom 7 (ifeq_axiom) } 38.68/38.87 complement(a) 38.68/38.87 38.68/38.87 Lemma 28: join(X, join(Y, meet(Z, X))) = join(X, Y). 38.68/38.87 Proof: 38.68/38.87 join(X, join(Y, meet(Z, X))) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 join(X, join(meet(Z, X), Y)) 38.68/38.87 = { by axiom 4 (associativity_of_join) } 38.68/38.87 join(join(X, meet(Z, X)), Y) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.87 join(Y, join(X, meet(Z, X))) 38.68/38.87 = { by axiom 5 (commutativity_of_meet) } 38.68/38.87 join(Y, join(X, meet(X, Z))) 38.68/38.87 = { by axiom 10 (absorption2) } 38.68/38.87 join(Y, X) 38.68/38.87 = { by axiom 6 (commutativity_of_join) } 38.68/38.88 join(X, Y) 38.68/38.88 38.68/38.88 Lemma 29: meet(b, complement(join(a, meet(b, complement(a))))) = zero. 38.68/38.88 Proof: 38.68/38.88 meet(b, complement(join(a, meet(b, complement(a))))) 38.68/38.88 = { by axiom 5 (commutativity_of_meet) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), b) 38.68/38.88 = { by lemma 25 } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)) 38.68/38.88 = { by lemma 26 } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), meet(b, join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b))))) 38.68/38.88 = { by lemma 25 } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(b, join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 10 (absorption2) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(b, meet(b, meet(?, a))), join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 5 (commutativity_of_meet) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(b, meet(b, meet(a, ?))), join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 12 (associativity_of_meet) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(b, meet(meet(b, a), ?)), join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 2 (prove_distributivity_hypothesis) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(b, meet(a, ?)), join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 5 (commutativity_of_meet) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(b, meet(?, a)), join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 6 (commutativity_of_join) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(meet(?, a), b), join(meet(?, a), meet(join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))), b)))) 38.68/38.88 = { by axiom 5 (commutativity_of_meet) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), meet(join(meet(?, a), b), join(meet(?, a), meet(b, join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a))))))) 38.68/38.88 = { by lemma 18 } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), join(meet(?, a), meet(b, join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a)))))) 38.68/38.88 = { by axiom 6 (commutativity_of_join) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), join(meet(?, a), meet(b, join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))))) 38.68/38.88 = { by lemma 27 } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), join(meet(?, a), meet(b, complement(a)))) 38.68/38.88 = { by axiom 6 (commutativity_of_join) } 38.68/38.88 meet(complement(join(a, meet(b, complement(a)))), join(meet(b, complement(a)), meet(?, a))) 38.68/38.88 = { by axiom 5 (commutativity_of_meet) } 38.68/38.88 meet(join(meet(b, complement(a)), meet(?, a)), complement(join(a, meet(b, complement(a))))) 38.68/38.88 = { by lemma 28 } 38.68/38.88 meet(join(meet(b, complement(a)), meet(?, a)), complement(join(a, join(meet(b, complement(a)), meet(?, a))))) 38.68/38.88 = { by axiom 6 (commutativity_of_join) } 38.68/38.88 meet(join(meet(b, complement(a)), meet(?, a)), complement(join(join(meet(b, complement(a)), meet(?, a)), a))) 38.68/38.88 = { by lemma 25 } 38.68/38.88 meet(join(meet(b, complement(a)), meet(?, a)), meet(join(join(meet(b, complement(a)), meet(?, a)), a), complement(join(join(meet(b, complement(a)), meet(?, a)), a)))) 38.68/38.88 = { by axiom 13 (complement_meet) } 38.68/38.88 meet(join(meet(b, complement(a)), meet(?, a)), zero) 38.68/38.88 = { by axiom 5 (commutativity_of_meet) } 38.68/38.88 meet(zero, join(meet(b, complement(a)), meet(?, a))) 38.68/38.88 = { by lemma 22 } 38.68/38.88 meet(zero, join(zero, join(meet(b, complement(a)), meet(?, a)))) 38.68/38.88 = { by axiom 3 (absorption1) } 38.68/38.90 zero 38.68/38.90 38.68/38.90 Goal 1 (prove_distributivity): complement(a) = join(complement(b), complement(a)). 38.68/38.90 Proof: 38.68/38.90 complement(a) 38.68/38.90 = { by axiom 9 (idempotence_of_join) } 38.68/38.90 join(complement(a), complement(a)) 38.68/38.90 = { by lemma 27 } 38.68/38.90 join(complement(a), join(meet(b, complement(a)), complement(join(a, meet(b, complement(a)))))) 38.68/38.90 = { by axiom 6 (commutativity_of_join) } 38.68/38.90 join(complement(a), join(complement(join(a, meet(b, complement(a)))), meet(b, complement(a)))) 38.68/38.90 = { by lemma 28 } 38.68/38.90 join(complement(a), complement(join(a, meet(b, complement(a))))) 38.68/38.90 = { by lemma 15 } 38.68/38.90 join(complement(a), complement(complement(complement(join(a, meet(b, complement(a))))))) 38.68/38.90 = { by axiom 7 (ifeq_axiom) } 38.68/38.90 join(complement(a), complement(ifeq(one, one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 21 } 38.68/38.90 join(complement(a), complement(ifeq(join(b, one), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by axiom 11 (complement_join) } 38.68/38.90 join(complement(a), complement(ifeq(join(b, join(meet(b, join(a, meet(complement(a), b))), complement(meet(b, join(a, meet(complement(a), b)))))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by axiom 6 (commutativity_of_join) } 38.68/38.90 join(complement(a), complement(ifeq(join(b, join(complement(meet(b, join(a, meet(complement(a), b)))), meet(b, join(a, meet(complement(a), b))))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 16 } 38.68/38.90 join(complement(a), complement(ifeq(join(b, complement(meet(b, join(a, meet(complement(a), b))))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 19 } 38.68/38.90 join(complement(a), complement(ifeq(join(b, complement(join(a, meet(complement(a), b)))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by axiom 5 (commutativity_of_meet) } 38.68/38.90 join(complement(a), complement(ifeq(join(b, complement(join(a, meet(b, complement(a))))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 20 } 38.68/38.90 join(complement(a), complement(ifeq(join(b, meet(complement(join(a, meet(b, complement(a)))), one)), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 23 } 38.68/38.90 join(complement(a), complement(ifeq(join(b, meet(complement(join(a, meet(b, complement(a)))), complement(zero))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 29 } 38.68/38.90 join(complement(a), complement(ifeq(join(b, meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a)))))))), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by axiom 6 (commutativity_of_join) } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, complement(complement(join(a, meet(b, complement(a))))), b))) 38.68/38.90 = { by lemma 20 } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, complement(meet(complement(join(a, meet(b, complement(a)))), one)), b))) 38.68/38.90 = { by lemma 23 } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, complement(meet(complement(join(a, meet(b, complement(a)))), complement(zero))), b))) 38.68/38.90 = { by lemma 29 } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, complement(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a)))))))), b))) 38.68/38.90 = { by axiom 7 (ifeq_axiom) } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, ifeq(zero, zero, complement(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a)))))))), b), b))) 38.68/38.90 = { by axiom 13 (complement_meet) } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, ifeq(meet(meet(b, complement(join(a, meet(b, complement(a))))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), zero, complement(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a)))))))), b), b))) 38.68/38.90 = { by axiom 12 (associativity_of_meet) } 38.68/38.90 join(complement(a), complement(ifeq(join(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a))))))), b), one, ifeq(meet(b, meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a)))))))), zero, complement(meet(complement(join(a, meet(b, complement(a)))), complement(meet(b, complement(join(a, meet(b, complement(a)))))))), b), b))) 38.68/38.90 = { by lemma 14 } 38.68/38.90 join(complement(a), complement(b)) 38.68/38.90 = { by axiom 6 (commutativity_of_join) } 38.68/38.90 join(complement(b), complement(a)) 38.68/38.90 % SZS output end Proof 38.68/38.90 38.68/38.90 RESULT: Unsatisfiable (the axioms are contradictory). 38.68/38.90 EOF