0.03/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.03/0.13 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.13/0.34 % Computer : n005.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 14:11:18 EDT 2019 0.13/0.34 % CPUTime : 117.72/117.94 % SZS status Unsatisfiable 117.72/117.94 117.72/117.94 % SZS output start Proof 117.72/117.94 Take the following subset of the input axioms: 117.72/117.94 fof(absorption1, axiom, ![X, Y]: meet(X, join(X, Y))=X). 117.72/117.94 fof(absorption2, axiom, ![X, Y]: join(X, meet(X, Y))=X). 117.72/117.94 fof(associativity_of_join, axiom, ![X, Y, Z]: join(join(X, Y), Z)=join(X, join(Y, Z))). 117.72/117.94 fof(associativity_of_meet, axiom, ![X, Y, Z]: meet(X, meet(Y, Z))=meet(meet(X, Y), Z)). 117.72/117.94 fof(commutativity_of_join, axiom, ![X, Y]: join(X, Y)=join(Y, X)). 117.72/117.94 fof(commutativity_of_meet, axiom, ![X, Y]: meet(Y, X)=meet(X, Y)). 117.72/117.94 fof(complement_join, axiom, ![X]: one=join(X, complement(X))). 117.72/117.94 fof(complement_meet, axiom, ![X]: meet(X, complement(X))=zero). 117.72/117.94 fof(equation_H11, axiom, ![X, Y, Z]: meet(X, join(Y, meet(Z, join(X, meet(Y, join(Z, meet(X, Y)))))))=meet(X, join(Y, meet(X, Z)))). 117.72/117.94 fof(idempotence_of_meet, axiom, ![X]: X=meet(X, X)). 117.72/117.94 fof(ifeq_axiom, axiom, ![B, A, C]: B=ifeq(A, A, B, C)). 117.72/117.94 fof(meet_join_complement, axiom, ![X, Y]: ifeq(join(X, Y), one, ifeq(meet(X, Y), zero, complement(X), Y), Y)=Y). 117.72/117.94 fof(prove_distributivity, negated_conjecture, meet(a, join(b, c))!=join(meet(a, b), meet(a, c))). 117.72/117.94 117.72/117.94 Now clausify the problem and encode Horn clauses using encoding 3 of 117.72/117.94 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 117.72/117.94 We repeatedly replace C & s=t => u=v by the two clauses: 117.72/117.94 fresh(y, y, x1...xn) = u 117.72/117.94 C => fresh(s, t, x1...xn) = v 117.72/117.94 where fresh is a fresh function symbol and x1..xn are the free 117.72/117.94 variables of u and v. 117.72/117.94 A predicate p(X) is encoded as p(X)=true (this is sound, because the 117.72/117.94 input problem has no model of domain size 1). 117.72/117.94 117.72/117.94 The encoding turns the above axioms into the following unit equations and goals: 117.72/117.94 117.72/117.94 Axiom 1 (ifeq_axiom): X = ifeq(Y, Y, X, Z). 117.72/117.94 Axiom 2 (idempotence_of_meet): X = meet(X, X). 117.72/117.94 Axiom 3 (commutativity_of_meet): meet(X, Y) = meet(Y, X). 117.72/117.94 Axiom 4 (absorption2): join(X, meet(X, Y)) = X. 117.72/117.94 Axiom 5 (complement_join): one = join(X, complement(X)). 117.72/117.94 Axiom 6 (associativity_of_meet): meet(X, meet(Y, Z)) = meet(meet(X, Y), Z). 117.72/117.94 Axiom 7 (associativity_of_join): join(join(X, Y), Z) = join(X, join(Y, Z)). 117.72/117.94 Axiom 8 (commutativity_of_join): join(X, Y) = join(Y, X). 117.72/117.94 Axiom 9 (complement_meet): meet(X, complement(X)) = zero. 117.72/117.94 Axiom 10 (absorption1): meet(X, join(X, Y)) = X. 117.72/117.94 Axiom 11 (meet_join_complement): ifeq(join(X, Y), one, ifeq(meet(X, Y), zero, complement(X), Y), Y) = Y. 117.92/118.14 Axiom 12 (equation_H11): meet(X, join(Y, meet(Z, join(X, meet(Y, join(Z, meet(X, Y))))))) = meet(X, join(Y, meet(X, Z))). 117.92/118.14 117.92/118.14 Lemma 13: meet(X, meet(Y, join(Z, meet(X, Y)))) = meet(X, Y). 117.92/118.14 Proof: 117.92/118.14 meet(X, meet(Y, join(Z, meet(X, Y)))) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 meet(X, meet(Y, join(meet(X, Y), Z))) 117.92/118.14 = { by axiom 6 (associativity_of_meet) } 117.92/118.14 meet(meet(X, Y), join(meet(X, Y), Z)) 117.92/118.14 = { by axiom 10 (absorption1) } 117.92/118.14 meet(X, Y) 117.92/118.14 117.92/118.14 Lemma 14: join(X, meet(Y, X)) = X. 117.92/118.14 Proof: 117.92/118.14 join(X, meet(Y, X)) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 join(X, meet(X, Y)) 117.92/118.14 = { by axiom 4 (absorption2) } 117.92/118.14 X 117.92/118.14 117.92/118.14 Lemma 15: join(meet(X, Z), meet(X, join(Y, meet(X, Z)))) = meet(X, join(Y, meet(X, Z))). 117.92/118.14 Proof: 117.92/118.14 join(meet(X, Z), meet(X, join(Y, meet(X, Z)))) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 join(meet(Z, X), meet(X, join(Y, meet(X, Z)))) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 join(meet(Z, X), meet(X, join(Y, meet(Z, X)))) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 join(meet(X, join(Y, meet(Z, X))), meet(Z, X)) 117.92/118.14 = { by lemma 13 } 117.92/118.14 join(meet(X, join(Y, meet(Z, X))), meet(Z, meet(X, join(Y, meet(Z, X))))) 117.92/118.14 = { by lemma 14 } 117.92/118.14 meet(X, join(Y, meet(Z, X))) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 meet(X, join(Y, meet(X, Z))) 117.92/118.14 117.92/118.14 Lemma 16: join(X, join(Y, meet(Z, join(X, Y)))) = join(X, Y). 117.92/118.14 Proof: 117.92/118.14 join(X, join(Y, meet(Z, join(X, Y)))) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 join(X, join(Y, meet(join(X, Y), Z))) 117.92/118.14 = { by axiom 7 (associativity_of_join) } 117.92/118.14 join(join(X, Y), meet(join(X, Y), Z)) 117.92/118.14 = { by axiom 4 (absorption2) } 117.92/118.14 join(X, Y) 117.92/118.14 117.92/118.14 Lemma 17: complement(complement(X)) = X. 117.92/118.14 Proof: 117.92/118.14 complement(complement(X)) 117.92/118.14 = { by axiom 1 (ifeq_axiom) } 117.92/118.14 ifeq(one, one, complement(complement(X)), X) 117.92/118.14 = { by axiom 5 (complement_join) } 117.92/118.14 ifeq(join(X, complement(X)), one, complement(complement(X)), X) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 ifeq(join(complement(X), X), one, complement(complement(X)), X) 117.92/118.14 = { by axiom 1 (ifeq_axiom) } 117.92/118.14 ifeq(join(complement(X), X), one, ifeq(zero, zero, complement(complement(X)), X), X) 117.92/118.14 = { by axiom 9 (complement_meet) } 117.92/118.14 ifeq(join(complement(X), X), one, ifeq(meet(X, complement(X)), zero, complement(complement(X)), X), X) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 ifeq(join(complement(X), X), one, ifeq(meet(complement(X), X), zero, complement(complement(X)), X), X) 117.92/118.14 = { by axiom 11 (meet_join_complement) } 117.92/118.14 X 117.92/118.14 117.92/118.14 Lemma 18: meet(X, meet(Y, Z)) = meet(Z, meet(X, Y)). 117.92/118.14 Proof: 117.92/118.14 meet(X, meet(Y, Z)) 117.92/118.14 = { by axiom 6 (associativity_of_meet) } 117.92/118.14 meet(meet(X, Y), Z) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 meet(Z, meet(X, Y)) 117.92/118.14 117.92/118.14 Lemma 19: meet(X, join(Y, X)) = X. 117.92/118.14 Proof: 117.92/118.14 meet(X, join(Y, X)) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 meet(X, join(X, Y)) 117.92/118.14 = { by axiom 10 (absorption1) } 117.92/118.14 X 117.92/118.14 117.92/118.14 Lemma 20: meet(Y, meet(join(X, Y), Z)) = meet(Y, Z). 117.92/118.14 Proof: 117.92/118.14 meet(Y, meet(join(X, Y), Z)) 117.92/118.14 = { by lemma 18 } 117.92/118.14 meet(join(X, Y), meet(Z, Y)) 117.92/118.14 = { by lemma 18 } 117.92/118.14 meet(Z, meet(Y, join(X, Y))) 117.92/118.14 = { by lemma 19 } 117.92/118.14 meet(Z, Y) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 meet(Y, Z) 117.92/118.14 117.92/118.14 Lemma 21: join(X, join(Z, meet(X, Y))) = join(X, Z). 117.92/118.14 Proof: 117.92/118.14 join(X, join(Z, meet(X, Y))) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 join(X, join(meet(X, Y), Z)) 117.92/118.14 = { by axiom 7 (associativity_of_join) } 117.92/118.14 join(join(X, meet(X, Y)), Z) 117.92/118.14 = { by axiom 4 (absorption2) } 117.92/118.14 join(X, Z) 117.92/118.14 117.92/118.14 Lemma 22: join(X, join(meet(X, Z), Y)) = join(X, Y). 117.92/118.14 Proof: 117.92/118.14 join(X, join(meet(X, Z), Y)) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 join(X, join(Y, meet(X, Z))) 117.92/118.14 = { by lemma 21 } 117.92/118.14 join(X, Y) 117.92/118.14 117.92/118.14 Lemma 23: join(X, meet(Z, join(meet(X, Y), meet(X, W)))) = X. 117.92/118.14 Proof: 117.92/118.14 join(X, meet(Z, join(meet(X, Y), meet(X, W)))) 117.92/118.14 = { by lemma 22 } 117.92/118.14 join(X, join(meet(X, Y), meet(Z, join(meet(X, Y), meet(X, W))))) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.14 join(X, join(meet(X, Y), meet(Z, join(meet(X, W), meet(X, Y))))) 117.92/118.14 = { by lemma 22 } 117.92/118.14 join(X, join(meet(X, W), join(meet(X, Y), meet(Z, join(meet(X, W), meet(X, Y)))))) 117.92/118.14 = { by lemma 16 } 117.92/118.14 join(X, join(meet(X, W), meet(X, Y))) 117.92/118.14 = { by lemma 22 } 117.92/118.14 join(X, meet(X, Y)) 117.92/118.14 = { by axiom 4 (absorption2) } 117.92/118.14 X 117.92/118.14 117.92/118.14 Lemma 24: join(X, meet(join(meet(Y, meet(Z, X)), meet(X, W)), V)) = X. 117.92/118.14 Proof: 117.92/118.14 join(X, meet(join(meet(Y, meet(Z, X)), meet(X, W)), V)) 117.92/118.14 = { by axiom 6 (associativity_of_meet) } 117.92/118.14 join(X, meet(join(meet(meet(Y, Z), X), meet(X, W)), V)) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 join(X, meet(join(meet(X, meet(Y, Z)), meet(X, W)), V)) 117.92/118.14 = { by axiom 3 (commutativity_of_meet) } 117.92/118.14 join(X, meet(V, join(meet(X, meet(Y, Z)), meet(X, W)))) 117.92/118.14 = { by lemma 23 } 117.92/118.14 X 117.92/118.14 117.92/118.14 Lemma 25: meet(X, one) = X. 117.92/118.14 Proof: 117.92/118.14 meet(X, one) 117.92/118.14 = { by axiom 5 (complement_join) } 117.92/118.14 meet(X, join(X, complement(X))) 117.92/118.14 = { by axiom 10 (absorption1) } 117.92/118.14 X 117.92/118.14 117.92/118.14 Lemma 26: meet(X, join(Y, meet(join(Y, X), complement(meet(X, Y))))) = meet(X, join(Y, meet(X, complement(meet(X, Y))))). 117.92/118.14 Proof: 117.92/118.14 meet(X, join(Y, meet(join(Y, X), complement(meet(X, Y))))) 117.92/118.14 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 meet(X, join(Y, meet(join(X, Y), complement(meet(X, Y))))) 117.92/118.15 = { by axiom 3 (commutativity_of_meet) } 117.92/118.15 meet(X, join(Y, meet(complement(meet(X, Y)), join(X, Y)))) 117.92/118.15 = { by lemma 25 } 117.92/118.15 meet(X, join(Y, meet(complement(meet(X, Y)), join(X, meet(Y, one))))) 117.92/118.15 = { by axiom 5 (complement_join) } 117.92/118.15 meet(X, join(Y, meet(complement(meet(X, Y)), join(X, meet(Y, join(meet(X, Y), complement(meet(X, Y)))))))) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 meet(X, join(Y, meet(complement(meet(X, Y)), join(X, meet(Y, join(complement(meet(X, Y)), meet(X, Y))))))) 117.92/118.15 = { by axiom 12 (equation_H11) } 117.92/118.15 meet(X, join(Y, meet(X, complement(meet(X, Y))))) 117.92/118.15 117.92/118.15 Lemma 27: meet(one, X) = X. 117.92/118.15 Proof: 117.92/118.15 meet(one, X) 117.92/118.15 = { by axiom 3 (commutativity_of_meet) } 117.92/118.15 meet(X, one) 117.92/118.15 = { by lemma 25 } 117.92/118.15 X 117.92/118.15 117.92/118.15 Lemma 28: join(X, one) = one. 117.92/118.15 Proof: 117.92/118.15 join(X, one) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 join(one, X) 117.92/118.15 = { by lemma 27 } 117.92/118.15 join(one, meet(one, X)) 117.92/118.15 = { by axiom 4 (absorption2) } 117.92/118.15 one 117.92/118.15 117.92/118.15 Lemma 29: join(one, X) = one. 117.92/118.15 Proof: 117.92/118.15 join(one, X) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 join(X, one) 117.92/118.15 = { by lemma 28 } 117.92/118.15 one 117.92/118.15 117.92/118.15 Lemma 30: join(X, join(Y, complement(X))) = one. 117.92/118.15 Proof: 117.92/118.15 join(X, join(Y, complement(X))) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 join(X, join(complement(X), Y)) 117.92/118.15 = { by axiom 7 (associativity_of_join) } 117.92/118.15 join(join(X, complement(X)), Y) 117.92/118.15 = { by axiom 5 (complement_join) } 117.92/118.15 join(one, Y) 117.92/118.15 = { by lemma 29 } 117.92/118.15 one 117.92/118.15 117.92/118.15 Lemma 31: join(X, complement(meet(X, Y))) = one. 117.92/118.15 Proof: 117.92/118.15 join(X, complement(meet(X, Y))) 117.92/118.15 = { by lemma 22 } 117.92/118.15 join(X, join(meet(X, Y), complement(meet(X, Y)))) 117.92/118.15 = { by axiom 5 (complement_join) } 117.92/118.15 join(X, one) 117.92/118.15 = { by lemma 28 } 117.92/118.15 one 117.92/118.15 117.92/118.15 Lemma 32: join(X, complement(meet(Y, X))) = one. 117.92/118.15 Proof: 117.92/118.15 join(X, complement(meet(Y, X))) 117.92/118.15 = { by axiom 3 (commutativity_of_meet) } 117.92/118.15 join(X, complement(meet(X, Y))) 117.92/118.15 = { by lemma 31 } 117.92/118.15 one 117.92/118.15 117.92/118.15 Lemma 33: meet(X, meet(Y, complement(meet(X, Y)))) = zero. 117.92/118.15 Proof: 117.92/118.15 meet(X, meet(Y, complement(meet(X, Y)))) 117.92/118.15 = { by axiom 6 (associativity_of_meet) } 117.92/118.15 meet(meet(X, Y), complement(meet(X, Y))) 117.92/118.15 = { by axiom 9 (complement_meet) } 117.92/118.15 zero 117.92/118.15 117.92/118.15 Lemma 34: meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y))))) = complement(Y). 117.92/118.15 Proof: 117.92/118.15 meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y))))) 117.92/118.15 = { by axiom 11 (meet_join_complement) } 117.92/118.15 ifeq(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 14 } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by axiom 3 (commutativity_of_meet) } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), join(Y, meet(join(X, complement(Y)), complement(meet(join(X, complement(Y)), Y)))))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 26 } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), join(Y, meet(join(Y, join(X, complement(Y))), complement(meet(join(X, complement(Y)), Y)))))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 30 } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), join(Y, meet(one, complement(meet(join(X, complement(Y)), Y)))))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 27 } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), join(Y, complement(meet(join(X, complement(Y)), Y))))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 32 } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), one)), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 25 } 117.92/118.15 ifeq(join(join(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), join(X, complement(Y))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by axiom 7 (associativity_of_join) } 117.92/118.15 ifeq(join(Y, join(meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y))))), join(X, complement(Y)))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by axiom 7 (associativity_of_join) } 117.92/118.15 ifeq(join(Y, join(join(meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y))))), X), complement(Y))), one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 30 } 117.92/118.15 ifeq(one, one, ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by axiom 1 (ifeq_axiom) } 117.92/118.15 ifeq(meet(Y, meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))), zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by lemma 33 } 117.92/118.15 ifeq(zero, zero, complement(Y), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))) 117.92/118.15 = { by axiom 1 (ifeq_axiom) } 117.92/118.15 complement(Y) 117.92/118.15 117.92/118.15 Lemma 35: meet(join(X, Y), complement(meet(complement(X), join(X, Y)))) = X. 117.92/118.15 Proof: 117.92/118.15 meet(join(X, Y), complement(meet(complement(X), join(X, Y)))) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 meet(join(Y, X), complement(meet(complement(X), join(X, Y)))) 117.92/118.15 = { by lemma 17 } 117.92/118.15 meet(join(Y, complement(complement(X))), complement(meet(complement(X), join(X, Y)))) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 meet(join(Y, complement(complement(X))), complement(meet(complement(X), join(Y, X)))) 117.92/118.15 = { by lemma 17 } 117.92/118.15 meet(join(Y, complement(complement(X))), complement(meet(complement(X), join(Y, complement(complement(X)))))) 117.92/118.15 = { by lemma 34 } 117.92/118.15 complement(complement(X)) 117.92/118.15 = { by lemma 17 } 117.92/118.15 X 117.92/118.15 117.92/118.15 Lemma 36: join(X, complement(meet(complement(X), join(X, Y)))) = complement(meet(complement(X), join(X, Y))). 117.92/118.15 Proof: 117.92/118.15 join(X, complement(meet(complement(X), join(X, Y)))) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 join(complement(meet(complement(X), join(X, Y))), X) 117.92/118.15 = { by lemma 35 } 117.92/118.15 join(complement(meet(complement(X), join(X, Y))), meet(join(X, Y), complement(meet(complement(X), join(X, Y))))) 117.92/118.15 = { by lemma 14 } 117.92/118.15 complement(meet(complement(X), join(X, Y))) 117.92/118.15 117.92/118.15 Lemma 37: meet(join(Y, X), complement(meet(complement(X), join(X, Y)))) = X. 117.92/118.15 Proof: 117.92/118.15 meet(join(Y, X), complement(meet(complement(X), join(X, Y)))) 117.92/118.15 = { by axiom 8 (commutativity_of_join) } 117.92/118.15 meet(join(X, Y), complement(meet(complement(X), join(X, Y)))) 117.92/118.15 = { by lemma 35 } 117.92/118.15 X 117.92/118.15 117.92/118.15 Lemma 38: meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y))))) = complement(X). 117.92/118.15 Proof: 117.92/118.15 meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y))))) 117.92/118.15 = { by axiom 11 (meet_join_complement) } 117.92/118.15 ifeq(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.15 = { by lemma 14 } 117.92/118.15 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.15 = { by axiom 3 (commutativity_of_meet) } 117.92/118.15 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.15 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, meet(complement(meet(Y, X)), complement(meet(X, complement(meet(X, Y)))))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, meet(complement(meet(Y, X)), complement(meet(X, complement(meet(Y, X)))))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, meet(complement(meet(Y, X)), complement(meet(complement(meet(Y, X)), X)))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 26 } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, meet(join(X, complement(meet(Y, X))), complement(meet(complement(meet(Y, X)), X)))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 32 } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, meet(one, complement(meet(complement(meet(Y, X)), X)))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 27 } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), join(X, complement(meet(complement(meet(Y, X)), X))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 32 } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(Y, X)), one)), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 25 } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), complement(meet(Y, X))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 ifeq(join(join(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), complement(meet(X, Y))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 7 (associativity_of_join) } 117.92/118.16 ifeq(join(X, join(meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y))))), complement(meet(X, Y)))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 ifeq(join(X, join(complement(meet(X, Y)), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y))))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 7 (associativity_of_join) } 117.92/118.16 ifeq(join(join(X, complement(meet(X, Y))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 31 } 117.92/118.16 ifeq(join(one, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 29 } 117.92/118.16 ifeq(one, one, ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 1 (ifeq_axiom) } 117.92/118.16 ifeq(meet(X, meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))), zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by lemma 33 } 117.92/118.16 ifeq(zero, zero, complement(X), meet(complement(meet(X, Y)), complement(meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 1 (ifeq_axiom) } 117.92/118.16 complement(X) 117.92/118.16 117.92/118.16 Lemma 39: meet(complement(X), complement(meet(complement(X), join(X, Y)))) = complement(join(X, Y)). 117.92/118.16 Proof: 117.92/118.16 meet(complement(X), complement(meet(complement(X), join(X, Y)))) 117.92/118.16 = { by lemma 37 } 117.92/118.16 meet(complement(meet(join(Y, X), complement(meet(complement(X), join(X, Y))))), complement(meet(complement(X), join(X, Y)))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(complement(meet(join(Y, X), complement(meet(complement(X), join(X, Y))))), complement(meet(complement(X), join(Y, X)))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(complement(meet(join(Y, X), complement(meet(complement(X), join(X, Y))))), complement(meet(join(Y, X), complement(X)))) 117.92/118.16 = { by lemma 37 } 117.92/118.16 meet(complement(meet(join(Y, X), complement(meet(complement(X), join(X, Y))))), complement(meet(join(Y, X), complement(meet(join(Y, X), complement(meet(complement(X), join(X, Y)))))))) 117.92/118.16 = { by lemma 38 } 117.92/118.16 complement(join(Y, X)) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 complement(join(X, Y)) 117.92/118.16 117.92/118.16 Lemma 40: complement(join(X, meet(complement(X), join(X, Y)))) = complement(join(X, Y)). 117.92/118.16 Proof: 117.92/118.16 complement(join(X, meet(complement(X), join(X, Y)))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 complement(join(X, meet(join(X, Y), complement(X)))) 117.92/118.16 = { by lemma 39 } 117.92/118.16 meet(complement(X), complement(meet(complement(X), join(X, meet(join(X, Y), complement(X)))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(complement(X), complement(meet(complement(X), join(X, meet(complement(X), join(X, Y)))))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(complement(X), complement(meet(complement(X), join(X, meet(complement(X), join(Y, X)))))) 117.92/118.16 = { by lemma 19 } 117.92/118.16 meet(complement(X), complement(meet(complement(X), meet(join(X, meet(complement(X), join(Y, X))), join(Y, join(X, meet(complement(X), join(Y, X)))))))) 117.92/118.16 = { by lemma 16 } 117.92/118.16 meet(complement(X), complement(meet(complement(X), meet(join(X, meet(complement(X), join(Y, X))), join(Y, X))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(complement(X), complement(meet(complement(X), meet(join(Y, X), join(X, meet(complement(X), join(Y, X))))))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(complement(X), complement(meet(complement(X), meet(join(X, Y), join(X, meet(complement(X), join(Y, X))))))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(complement(X), complement(meet(complement(X), meet(join(X, Y), join(X, meet(complement(X), join(X, Y))))))) 117.92/118.16 = { by lemma 13 } 117.92/118.16 meet(complement(X), complement(meet(complement(X), join(X, Y)))) 117.92/118.16 = { by lemma 39 } 117.92/118.16 complement(join(X, Y)) 117.92/118.16 117.92/118.16 Lemma 41: join(X, meet(complement(X), join(X, Y))) = join(X, Y). 117.92/118.16 Proof: 117.92/118.16 join(X, meet(complement(X), join(X, Y))) 117.92/118.16 = { by lemma 17 } 117.92/118.16 complement(complement(join(X, meet(complement(X), join(X, Y))))) 117.92/118.16 = { by lemma 40 } 117.92/118.16 complement(complement(join(X, Y))) 117.92/118.16 = { by lemma 17 } 117.92/118.16 join(X, Y) 117.92/118.16 117.92/118.16 Lemma 42: complement(meet(complement(X), join(X, Y))) = join(X, complement(join(X, Y))). 117.92/118.16 Proof: 117.92/118.16 complement(meet(complement(X), join(X, Y))) 117.92/118.16 = { by lemma 36 } 117.92/118.16 join(X, complement(meet(complement(X), join(X, Y)))) 117.92/118.16 = { by lemma 41 } 117.92/118.16 join(X, meet(complement(X), join(X, complement(meet(complement(X), join(X, Y)))))) 117.92/118.16 = { by lemma 36 } 117.92/118.16 join(X, meet(complement(X), complement(meet(complement(X), join(X, Y))))) 117.92/118.16 = { by lemma 39 } 117.92/118.16 join(X, complement(join(X, Y))) 117.92/118.16 117.92/118.16 Lemma 43: join(X, join(Y, Z)) = join(Y, join(X, Z)). 117.92/118.16 Proof: 117.92/118.16 join(X, join(Y, Z)) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 join(join(Y, Z), X) 117.92/118.16 = { by axiom 7 (associativity_of_join) } 117.92/118.16 join(Y, join(Z, X)) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 join(Y, join(X, Z)) 117.92/118.16 117.92/118.16 Lemma 44: meet(join(X, Y), join(X, complement(join(X, Y)))) = X. 117.92/118.16 Proof: 117.92/118.16 meet(join(X, Y), join(X, complement(join(X, Y)))) 117.92/118.16 = { by lemma 24 } 117.92/118.16 meet(join(X, join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?))), join(X, complement(join(X, Y)))) 117.92/118.16 = { by lemma 43 } 117.92/118.16 meet(join(Y, join(X, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?))), join(X, complement(join(X, Y)))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(join(Y, join(meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?), X)), join(X, complement(join(X, Y)))) 117.92/118.16 = { by lemma 17 } 117.92/118.16 meet(join(Y, join(meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?), complement(complement(X)))), join(X, complement(join(X, Y)))) 117.92/118.16 = { by axiom 7 (associativity_of_join) } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), join(X, complement(join(X, Y)))) 117.92/118.16 = { by lemma 24 } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), join(X, complement(join(X, join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)))))) 117.92/118.16 = { by lemma 42 } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), complement(meet(complement(X), join(X, join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)))))) 117.92/118.16 = { by lemma 43 } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), complement(meet(complement(X), join(Y, join(X, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)))))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), complement(meet(complement(X), join(Y, join(meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?), X))))) 117.92/118.16 = { by lemma 17 } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), complement(meet(complement(X), join(Y, join(meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?), complement(complement(X))))))) 117.92/118.16 = { by axiom 7 (associativity_of_join) } 117.92/118.16 meet(join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X))), complement(meet(complement(X), join(join(Y, meet(join(meet(?, meet(?, Y)), meet(Y, ?)), ?)), complement(complement(X)))))) 117.92/118.16 = { by lemma 34 } 117.92/118.16 complement(complement(X)) 117.92/118.16 = { by lemma 17 } 117.92/118.16 X 117.92/118.16 117.92/118.16 Lemma 45: meet(X, join(Y, complement(join(X, Y)))) = meet(X, Y). 117.92/118.16 Proof: 117.92/118.16 meet(X, join(Y, complement(join(X, Y)))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(X, join(Y, complement(join(Y, X)))) 117.92/118.16 = { by lemma 20 } 117.92/118.16 meet(X, meet(join(Y, X), join(Y, complement(join(Y, X))))) 117.92/118.16 = { by lemma 44 } 117.92/118.16 meet(X, Y) 117.92/118.16 117.92/118.16 Lemma 46: join(X, join(Y, complement(join(X, Y)))) = one. 117.92/118.16 Proof: 117.92/118.16 join(X, join(Y, complement(join(X, Y)))) 117.92/118.16 = { by axiom 7 (associativity_of_join) } 117.92/118.16 join(join(X, Y), complement(join(X, Y))) 117.92/118.16 = { by axiom 5 (complement_join) } 117.92/118.16 one 117.92/118.16 117.92/118.16 Lemma 47: join(meet(X, complement(meet(X, Y))), complement(join(Y, meet(X, complement(meet(X, Y)))))) = complement(Y). 117.92/118.16 Proof: 117.92/118.16 join(meet(X, complement(meet(X, Y))), complement(join(Y, meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(X, Y)))))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X)))))) 117.92/118.16 = { by axiom 11 (meet_join_complement) } 117.92/118.16 ifeq(join(Y, join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))), one, ifeq(meet(Y, join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))), zero, complement(Y), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))) 117.92/118.16 = { by lemma 46 } 117.92/118.16 ifeq(one, one, ifeq(meet(Y, join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))), zero, complement(Y), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))) 117.92/118.16 = { by axiom 1 (ifeq_axiom) } 117.92/118.16 ifeq(meet(Y, join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))), zero, complement(Y), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))) 117.92/118.16 = { by lemma 45 } 117.92/118.16 ifeq(meet(Y, meet(X, complement(meet(Y, X)))), zero, complement(Y), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))) 117.92/118.16 = { by lemma 33 } 117.92/118.16 ifeq(zero, zero, complement(Y), join(meet(X, complement(meet(Y, X))), complement(join(Y, meet(X, complement(meet(Y, X))))))) 117.92/118.16 = { by axiom 1 (ifeq_axiom) } 117.92/118.16 complement(Y) 117.92/118.16 117.92/118.16 Lemma 48: meet(join(Y, X), join(X, meet(Y, Z))) = join(X, meet(Y, Z)). 117.92/118.16 Proof: 117.92/118.16 meet(join(Y, X), join(X, meet(Y, Z))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(join(X, Y), join(X, meet(Y, Z))) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 meet(join(Y, X), join(X, meet(Y, Z))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(join(X, meet(Y, Z)), join(Y, X)) 117.92/118.16 = { by lemma 21 } 117.92/118.16 meet(join(X, meet(Y, Z)), join(Y, join(X, meet(Y, Z)))) 117.92/118.16 = { by lemma 19 } 117.92/118.16 join(X, meet(Y, Z)) 117.92/118.16 117.92/118.16 Lemma 49: meet(X, meet(Y, X)) = meet(X, Y). 117.92/118.16 Proof: 117.92/118.16 meet(X, meet(Y, X)) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(X, meet(X, Y)) 117.92/118.16 = { by axiom 6 (associativity_of_meet) } 117.92/118.16 meet(meet(X, X), Y) 117.92/118.16 = { by axiom 2 (idempotence_of_meet) } 117.92/118.16 meet(X, Y) 117.92/118.16 117.92/118.16 Lemma 50: join(X, zero) = X. 117.92/118.16 Proof: 117.92/118.16 join(X, zero) 117.92/118.16 = { by axiom 9 (complement_meet) } 117.92/118.16 join(X, meet(X, complement(X))) 117.92/118.16 = { by axiom 4 (absorption2) } 117.92/118.16 X 117.92/118.16 117.92/118.16 Lemma 51: join(zero, X) = X. 117.92/118.16 Proof: 117.92/118.16 join(zero, X) 117.92/118.16 = { by axiom 8 (commutativity_of_join) } 117.92/118.16 join(X, zero) 117.92/118.16 = { by lemma 50 } 117.92/118.16 X 117.92/118.16 117.92/118.16 Lemma 52: meet(X, join(meet(Y, complement(X)), meet(Z, complement(X)))) = zero. 117.92/118.16 Proof: 117.92/118.16 meet(X, join(meet(Y, complement(X)), meet(Z, complement(X)))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(X, join(meet(complement(X), Y), meet(Z, complement(X)))) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(X, join(meet(complement(X), Y), meet(complement(X), Z))) 117.92/118.16 = { by lemma 48 } 117.92/118.16 meet(X, meet(join(complement(X), meet(complement(X), Y)), join(meet(complement(X), Y), meet(complement(X), Z)))) 117.92/118.16 = { by axiom 4 (absorption2) } 117.92/118.16 meet(X, meet(complement(X), join(meet(complement(X), Y), meet(complement(X), Z)))) 117.92/118.16 = { by lemma 18 } 117.92/118.16 meet(complement(X), meet(join(meet(complement(X), Y), meet(complement(X), Z)), X)) 117.92/118.16 = { by lemma 18 } 117.92/118.16 meet(join(meet(complement(X), Y), meet(complement(X), Z)), meet(X, complement(X))) 117.92/118.16 = { by axiom 9 (complement_meet) } 117.92/118.16 meet(join(meet(complement(X), Y), meet(complement(X), Z)), zero) 117.92/118.16 = { by axiom 3 (commutativity_of_meet) } 117.92/118.16 meet(zero, join(meet(complement(X), Y), meet(complement(X), Z))) 117.92/118.16 = { by lemma 51 } 117.92/118.16 join(zero, meet(zero, join(meet(complement(X), Y), meet(complement(X), Z)))) 117.92/118.16 = { by axiom 4 (absorption2) } 117.92/118.18 zero 117.92/118.18 117.92/118.18 Lemma 53: join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y))))) = complement(Y). 117.92/118.18 Proof: 117.92/118.18 join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y))))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(meet(X, complement(Y)), complement(join(meet(X, complement(Y)), Y))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y))))) 117.92/118.18 = { by axiom 11 (meet_join_complement) } 117.92/118.18 ifeq(join(Y, join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))), one, ifeq(meet(Y, join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 46 } 117.92/118.18 ifeq(one, one, ifeq(meet(Y, join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 1 (ifeq_axiom) } 117.92/118.18 ifeq(meet(Y, join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 ifeq(meet(Y, join(meet(X, complement(Y)), complement(join(meet(X, complement(Y)), Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 ifeq(meet(Y, join(complement(join(meet(X, complement(Y)), Y)), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 ifeq(meet(Y, join(complement(join(meet(X, complement(Y)), complement(complement(Y)))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 38 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))))), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 34 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(complement(complement(Y))), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))), join(meet(X, complement(Y)), complement(complement(Y)))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 14 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))), join(join(meet(X, complement(Y)), complement(complement(Y))), meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(meet(complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))), join(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))), join(meet(X, complement(Y)), complement(complement(Y))))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 20 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), meet(join(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))), join(meet(X, complement(Y)), complement(complement(Y)))), complement(meet(complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))), join(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))), join(meet(X, complement(Y)), complement(complement(Y)))))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 35 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 49 } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(join(meet(X, complement(Y)), complement(complement(Y))), complement(Y)))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 ifeq(meet(Y, join(meet(complement(Y), complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y)))))), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 ifeq(meet(Y, join(meet(complement(meet(complement(Y), join(meet(X, complement(Y)), complement(complement(Y))))), complement(Y)), meet(X, complement(Y)))), zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by lemma 52 } 117.92/118.18 ifeq(zero, zero, complement(Y), join(meet(X, complement(Y)), complement(join(Y, meet(X, complement(Y)))))) 117.92/118.18 = { by axiom 1 (ifeq_axiom) } 117.92/118.18 complement(Y) 117.92/118.18 117.92/118.18 Lemma 54: join(meet(X, Y), complement(join(complement(X), meet(X, Y)))) = X. 117.92/118.18 Proof: 117.92/118.18 join(meet(X, Y), complement(join(complement(X), meet(X, Y)))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 join(meet(Y, X), complement(join(complement(X), meet(X, Y)))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 join(meet(Y, complement(complement(X))), complement(join(complement(X), meet(X, Y)))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 join(meet(Y, complement(complement(X))), complement(join(complement(X), meet(Y, X)))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 join(meet(Y, complement(complement(X))), complement(join(complement(X), meet(Y, complement(complement(X)))))) 117.92/118.18 = { by lemma 53 } 117.92/118.18 complement(complement(X)) 117.92/118.18 = { by lemma 17 } 117.92/118.18 X 117.92/118.18 117.92/118.18 Lemma 55: complement(meet(X, complement(meet(X, Y)))) = join(complement(X), meet(X, Y)). 117.92/118.18 Proof: 117.92/118.18 complement(meet(X, complement(meet(X, Y)))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 complement(meet(complement(meet(X, Y)), X)) 117.92/118.18 = { by axiom 4 (absorption2) } 117.92/118.18 join(complement(meet(complement(meet(X, Y)), X)), meet(complement(meet(complement(meet(X, Y)), X)), complement(meet(complement(meet(X, Y)), complement(meet(complement(meet(X, Y)), X)))))) 117.92/118.18 = { by lemma 38 } 117.92/118.18 join(complement(meet(complement(meet(X, Y)), X)), complement(complement(meet(X, Y)))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(complement(complement(meet(X, Y))), complement(meet(complement(meet(X, Y)), X))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 join(meet(X, Y), complement(meet(complement(meet(X, Y)), X))) 117.92/118.18 = { by lemma 13 } 117.92/118.18 join(meet(X, Y), complement(meet(complement(meet(X, Y)), meet(X, join(meet(X, Y), meet(complement(meet(X, Y)), X)))))) 117.92/118.18 = { by lemma 14 } 117.92/118.18 join(meet(X, Y), complement(meet(complement(meet(X, Y)), meet(join(X, meet(complement(meet(X, Y)), X)), join(meet(X, Y), meet(complement(meet(X, Y)), X)))))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(meet(X, Y), complement(meet(complement(meet(X, Y)), meet(join(X, meet(complement(meet(X, Y)), X)), join(meet(complement(meet(X, Y)), X), meet(X, Y)))))) 117.92/118.18 = { by lemma 48 } 117.92/118.18 join(meet(X, Y), complement(meet(complement(meet(X, Y)), join(meet(complement(meet(X, Y)), X), meet(X, Y))))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(meet(X, Y), complement(meet(complement(meet(X, Y)), join(meet(X, Y), meet(complement(meet(X, Y)), X))))) 117.92/118.18 = { by lemma 36 } 117.92/118.18 complement(meet(complement(meet(X, Y)), join(meet(X, Y), meet(complement(meet(X, Y)), X)))) 117.92/118.18 = { by lemma 42 } 117.92/118.18 join(meet(X, Y), complement(join(meet(X, Y), meet(complement(meet(X, Y)), X)))) 117.92/118.18 = { by lemma 54 } 117.92/118.18 join(meet(X, Y), complement(join(meet(X, Y), meet(complement(meet(X, Y)), join(meet(X, Y), complement(join(complement(X), meet(X, Y)))))))) 117.92/118.18 = { by lemma 41 } 117.92/118.18 join(meet(X, Y), complement(join(meet(X, Y), complement(join(complement(X), meet(X, Y)))))) 117.92/118.18 = { by lemma 54 } 117.92/118.18 join(meet(X, Y), complement(X)) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(complement(X), meet(X, Y)) 117.92/118.18 117.92/118.18 Lemma 56: join(complement(X), meet(Y, meet(Z, complement(X)))) = complement(X). 117.92/118.18 Proof: 117.92/118.18 join(complement(X), meet(Y, meet(Z, complement(X)))) 117.92/118.18 = { by lemma 50 } 117.92/118.18 join(complement(X), meet(Y, join(meet(Z, complement(X)), zero))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 join(complement(X), meet(Y, join(meet(complement(X), Z), zero))) 117.92/118.18 = { by lemma 52 } 117.92/118.18 join(complement(X), meet(Y, join(meet(complement(X), Z), meet(complement(X), join(meet(?, complement(complement(X))), meet(?, complement(complement(X)))))))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 join(complement(X), meet(Y, join(meet(complement(X), Z), meet(complement(X), join(meet(?, X), meet(?, complement(complement(X)))))))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 join(complement(X), meet(Y, join(meet(complement(X), Z), meet(complement(X), join(meet(X, ?), meet(?, complement(complement(X)))))))) 117.92/118.18 = { by lemma 17 } 117.92/118.18 join(complement(X), meet(Y, join(meet(complement(X), Z), meet(complement(X), join(meet(X, ?), meet(?, X)))))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 join(complement(X), meet(Y, join(meet(complement(X), Z), meet(complement(X), join(meet(X, ?), meet(X, ?)))))) 117.92/118.18 = { by lemma 23 } 117.92/118.18 complement(X) 117.92/118.18 117.92/118.18 Lemma 57: meet(X, meet(Y, Z)) = meet(Y, meet(X, Z)). 117.92/118.18 Proof: 117.92/118.18 meet(X, meet(Y, Z)) 117.92/118.18 = { by axiom 6 (associativity_of_meet) } 117.92/118.18 meet(meet(X, Y), Z) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 meet(meet(Y, X), Z) 117.92/118.18 = { by axiom 6 (associativity_of_meet) } 117.92/118.18 meet(Y, meet(X, Z)) 117.92/118.18 117.92/118.18 Lemma 58: join(meet(X, meet(Y, W)), meet(W, join(Y, Z))) = meet(W, join(Y, Z)). 117.92/118.18 Proof: 117.92/118.18 join(meet(X, meet(Y, W)), meet(W, join(Y, Z))) 117.92/118.18 = { by lemma 57 } 117.92/118.18 join(meet(Y, meet(X, W)), meet(W, join(Y, Z))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 join(meet(Y, meet(W, X)), meet(W, join(Y, Z))) 117.92/118.18 = { by lemma 57 } 117.92/118.18 join(meet(W, meet(Y, X)), meet(W, join(Y, Z))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(meet(W, meet(Y, X)), meet(W, join(Z, Y))) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 join(meet(W, join(Z, Y)), meet(W, meet(Y, X))) 117.92/118.18 = { by lemma 20 } 117.92/118.18 join(meet(W, join(Z, Y)), meet(W, meet(Y, meet(join(Z, Y), X)))) 117.92/118.18 = { by lemma 18 } 117.92/118.18 join(meet(W, join(Z, Y)), meet(W, meet(join(Z, Y), meet(X, Y)))) 117.92/118.18 = { by axiom 6 (associativity_of_meet) } 117.92/118.18 join(meet(W, join(Z, Y)), meet(meet(W, join(Z, Y)), meet(X, Y))) 117.92/118.18 = { by axiom 4 (absorption2) } 117.92/118.18 meet(W, join(Z, Y)) 117.92/118.18 = { by axiom 8 (commutativity_of_join) } 117.92/118.18 meet(W, join(Y, Z)) 117.92/118.18 117.92/118.18 Lemma 59: meet(X, complement(meet(X, Y))) = meet(X, complement(Y)). 117.92/118.18 Proof: 117.92/118.18 meet(X, complement(meet(X, Y))) 117.92/118.18 = { by axiom 10 (absorption1) } 117.92/118.18 meet(meet(X, complement(meet(X, Y))), join(meet(X, complement(meet(X, Y))), complement(join(Y, meet(X, complement(meet(X, Y))))))) 117.92/118.18 = { by lemma 47 } 117.92/118.18 meet(meet(X, complement(meet(X, Y))), complement(Y)) 117.92/118.18 = { by axiom 6 (associativity_of_meet) } 117.92/118.18 meet(X, meet(complement(meet(X, Y)), complement(Y))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 meet(X, meet(complement(Y), complement(meet(X, Y)))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 meet(X, meet(complement(Y), complement(meet(Y, X)))) 117.92/118.18 = { by axiom 3 (commutativity_of_meet) } 117.92/118.18 meet(X, meet(complement(meet(Y, X)), complement(Y))) 117.92/118.18 = { by lemma 38 } 117.92/118.18 meet(X, meet(complement(meet(Y, X)), meet(complement(meet(Y, X)), complement(meet(Y, complement(meet(Y, X))))))) 117.92/118.18 = { by lemma 56 } 117.92/118.18 meet(X, meet(complement(meet(Y, X)), meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X)))))))))) 117.92/118.18 = { by lemma 58 } 117.92/118.18 meet(X, meet(complement(meet(Y, X)), join(meet(?, meet(complement(meet(Y, complement(meet(Y, X)))), complement(meet(Y, X)))), meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X))))))))))) 117.92/118.18 = { by lemma 15 } 117.92/118.18 meet(X, join(meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X)))))))), meet(complement(meet(Y, X)), join(meet(?, meet(complement(meet(Y, complement(meet(Y, X)))), complement(meet(Y, X)))), meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X)))))))))))) 117.92/118.18 = { by lemma 58 } 117.92/118.18 meet(X, join(meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X)))))))), meet(complement(meet(Y, X)), meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X))))))))))) 117.92/118.18 = { by lemma 14 } 117.92/118.18 meet(X, meet(complement(meet(Y, X)), join(complement(meet(Y, complement(meet(Y, X)))), meet(?, meet(?, complement(meet(Y, complement(meet(Y, X))))))))) 117.92/118.18 = { by lemma 56 } 117.92/118.18 meet(X, meet(complement(meet(Y, X)), complement(meet(Y, complement(meet(Y, X)))))) 117.92/118.18 = { by lemma 38 } 118.08/118.36 meet(X, complement(Y)) 118.08/118.36 118.08/118.36 Lemma 60: complement(meet(Y, complement(X))) = join(X, complement(Y)). 118.08/118.36 Proof: 118.08/118.36 complement(meet(Y, complement(X))) 118.08/118.36 = { by lemma 50 } 118.08/118.36 complement(join(meet(Y, complement(X)), zero)) 118.08/118.36 = { by lemma 59 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, X))), zero)) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(X, Y))), zero)) 118.08/118.36 = { by lemma 17 } 118.08/118.36 complement(join(meet(Y, complement(meet(X, complement(complement(Y))))), zero)) 118.08/118.36 = { by lemma 44 } 118.08/118.36 complement(join(meet(Y, complement(meet(join(meet(X, complement(complement(Y))), complement(join(complement(Y), meet(X, complement(complement(Y)))))), join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), complement(join(complement(Y), meet(X, complement(complement(Y))))))))))), zero)) 118.08/118.36 = { by lemma 53 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), complement(join(complement(Y), meet(X, complement(complement(Y))))))))))), zero)) 118.08/118.36 = { by axiom 8 (commutativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), complement(Y))))))))), zero)) 118.08/118.36 = { by lemma 39 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), meet(complement(meet(X, complement(complement(Y)))), complement(meet(complement(meet(X, complement(complement(Y)))), join(meet(X, complement(complement(Y))), complement(Y))))))))))), zero)) 118.08/118.36 = { by lemma 36 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), meet(complement(meet(X, complement(complement(Y)))), join(meet(X, complement(complement(Y))), complement(meet(complement(meet(X, complement(complement(Y)))), join(meet(X, complement(complement(Y))), complement(Y)))))))))))), zero)) 118.08/118.36 = { by lemma 40 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(join(meet(X, complement(complement(Y))), complement(meet(complement(meet(X, complement(complement(Y)))), join(meet(X, complement(complement(Y))), complement(Y)))))))))), zero)) 118.08/118.36 = { by lemma 36 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(complement(meet(complement(meet(X, complement(complement(Y)))), join(meet(X, complement(complement(Y))), complement(Y))))))))), zero)) 118.08/118.36 = { by lemma 17 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), meet(complement(meet(X, complement(complement(Y)))), join(meet(X, complement(complement(Y))), complement(Y))))))), zero)) 118.08/118.36 = { by lemma 41 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(meet(X, complement(complement(Y))), complement(Y))))), zero)) 118.08/118.36 = { by axiom 8 (commutativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(complement(Y), meet(X, complement(complement(Y))))))), zero)) 118.08/118.36 = { by lemma 17 } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(complement(complement(complement(Y))), meet(X, complement(complement(Y))))))), zero)) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(complement(complement(complement(Y))), meet(complement(complement(Y)), X))))), zero)) 118.08/118.36 = { by axiom 12 (equation_H11) } 118.08/118.36 complement(join(meet(Y, complement(meet(complement(complement(Y)), join(complement(complement(complement(Y))), meet(X, join(complement(complement(Y)), meet(complement(complement(complement(Y))), join(X, meet(complement(complement(Y)), complement(complement(complement(Y)))))))))))), zero)) 118.08/118.36 = { by lemma 17 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(complement(complement(Y))), meet(X, join(complement(complement(Y)), meet(complement(complement(complement(Y))), join(X, meet(complement(complement(Y)), complement(complement(complement(Y)))))))))))), zero)) 118.08/118.36 = { by lemma 17 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(complement(complement(Y)), meet(complement(complement(complement(Y))), join(X, meet(complement(complement(Y)), complement(complement(complement(Y)))))))))))), zero)) 118.08/118.36 = { by axiom 9 (complement_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(complement(complement(Y)), meet(complement(complement(complement(Y))), join(X, zero)))))))), zero)) 118.08/118.36 = { by lemma 50 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(complement(complement(Y)), meet(complement(complement(complement(Y))), X))))))), zero)) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(complement(complement(Y)), meet(X, complement(complement(complement(Y)))))))))), zero)) 118.08/118.36 = { by lemma 17 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(complement(complement(Y)), meet(X, complement(Y)))))))), zero)) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(complement(complement(Y)), meet(complement(Y), X))))))), zero)) 118.08/118.36 = { by lemma 55 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, complement(meet(complement(Y), complement(meet(complement(Y), X))))))))), zero)) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, complement(meet(complement(Y), complement(meet(X, complement(Y)))))))))), zero)) 118.08/118.36 = { by lemma 59 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, complement(meet(X, meet(complement(Y), complement(meet(X, complement(Y))))))))))), zero)) 118.08/118.36 = { by lemma 33 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, complement(zero)))))), zero)) 118.08/118.36 = { by lemma 51 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, join(zero, complement(zero))))))), zero)) 118.08/118.36 = { by axiom 5 (complement_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), meet(X, one))))), zero)) 118.08/118.36 = { by lemma 25 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(complement(Y), X)))), zero)) 118.08/118.36 = { by axiom 8 (commutativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), zero)) 118.08/118.36 = { by axiom 9 (complement_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), meet(one, complement(one)))) 118.08/118.36 = { by lemma 27 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(one))) 118.08/118.36 = { by lemma 31 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(join(X, complement(Y)), complement(meet(join(X, complement(Y)), Y)))))) 118.08/118.36 = { by axiom 7 (associativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, join(complement(Y), complement(meet(join(X, complement(Y)), Y))))))) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, join(complement(Y), complement(meet(Y, join(X, complement(Y))))))))) 118.08/118.36 = { by axiom 8 (commutativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, join(complement(meet(Y, join(X, complement(Y)))), complement(Y)))))) 118.08/118.36 = { by lemma 34 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, join(complement(meet(Y, join(X, complement(Y)))), meet(join(X, complement(Y)), complement(meet(Y, join(X, complement(Y)))))))))) 118.08/118.36 = { by lemma 14 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, join(X, complement(Y)))))))) 118.08/118.36 = { by lemma 49 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, meet(join(X, complement(Y)), Y))))))) 118.08/118.36 = { by lemma 45 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, join(meet(join(X, complement(Y)), Y), complement(join(Y, meet(join(X, complement(Y)), Y)))))))))) 118.08/118.36 = { by lemma 14 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, join(meet(join(X, complement(Y)), Y), complement(Y)))))))) 118.08/118.36 = { by axiom 8 (commutativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, join(complement(Y), meet(join(X, complement(Y)), Y)))))))) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, join(complement(Y), meet(Y, join(X, complement(Y)))))))))) 118.08/118.36 = { by lemma 55 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, complement(meet(Y, complement(meet(Y, complement(meet(Y, join(X, complement(Y)))))))))))) 118.08/118.36 = { by lemma 55 } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(X, join(complement(Y), meet(Y, complement(meet(Y, join(X, complement(Y)))))))))) 118.08/118.36 = { by axiom 7 (associativity_of_join) } 118.08/118.36 complement(join(meet(Y, complement(meet(Y, join(X, complement(Y))))), complement(join(join(X, complement(Y)), meet(Y, complement(meet(Y, join(X, complement(Y))))))))) 118.08/118.36 = { by lemma 47 } 118.08/118.36 complement(complement(join(X, complement(Y)))) 118.08/118.36 = { by lemma 17 } 118.08/118.36 join(X, complement(Y)) 118.08/118.36 118.08/118.36 Lemma 61: meet(X, join(Z, meet(X, Y))) = meet(X, join(Y, Z)). 118.08/118.36 Proof: 118.08/118.36 meet(X, join(Z, meet(X, Y))) 118.08/118.36 = { by lemma 17 } 118.08/118.36 meet(X, join(complement(complement(Z)), meet(X, Y))) 118.08/118.36 = { by axiom 8 (commutativity_of_join) } 118.08/118.36 meet(X, join(meet(X, Y), complement(complement(Z)))) 118.08/118.36 = { by lemma 60 } 118.08/118.36 meet(X, complement(meet(complement(Z), complement(meet(X, Y))))) 118.08/118.36 = { by lemma 59 } 118.08/118.36 meet(X, complement(meet(X, meet(complement(Z), complement(meet(X, Y)))))) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 meet(X, complement(meet(X, meet(complement(meet(X, Y)), complement(Z))))) 118.08/118.36 = { by axiom 6 (associativity_of_meet) } 118.08/118.36 meet(X, complement(meet(meet(X, complement(meet(X, Y))), complement(Z)))) 118.08/118.36 = { by lemma 59 } 118.08/118.36 meet(X, complement(meet(meet(X, complement(Y)), complement(Z)))) 118.08/118.36 = { by axiom 6 (associativity_of_meet) } 118.08/118.36 meet(X, complement(meet(X, meet(complement(Y), complement(Z))))) 118.08/118.36 = { by axiom 3 (commutativity_of_meet) } 118.08/118.36 meet(X, complement(meet(X, meet(complement(Z), complement(Y))))) 118.08/118.36 = { by lemma 59 } 118.08/118.36 meet(X, complement(meet(complement(Z), complement(Y)))) 118.08/118.36 = { by lemma 60 } 118.08/118.36 meet(X, join(Y, complement(complement(Z)))) 118.08/118.36 = { by lemma 17 } 118.08/118.37 meet(X, join(Y, Z)) 118.08/118.37 118.08/118.37 Goal 1 (prove_distributivity): meet(a, join(b, c)) = join(meet(a, b), meet(a, c)). 118.08/118.37 Proof: 118.08/118.37 meet(a, join(b, c)) 118.08/118.37 = { by axiom 8 (commutativity_of_join) } 118.08/118.37 meet(a, join(c, b)) 118.08/118.37 = { by lemma 61 } 118.08/118.37 meet(a, join(b, meet(a, c))) 118.08/118.37 = { by axiom 8 (commutativity_of_join) } 118.08/118.37 meet(a, join(meet(a, c), b)) 118.08/118.37 = { by lemma 14 } 118.08/118.37 join(meet(a, join(meet(a, c), b)), meet(b, meet(a, join(meet(a, c), b)))) 118.08/118.37 = { by lemma 57 } 118.08/118.37 join(meet(a, join(meet(a, c), b)), meet(a, meet(b, join(meet(a, c), b)))) 118.08/118.37 = { by lemma 19 } 118.08/118.37 join(meet(a, join(meet(a, c), b)), meet(a, b)) 118.08/118.37 = { by axiom 3 (commutativity_of_meet) } 118.08/118.37 join(meet(a, join(meet(a, c), b)), meet(b, a)) 118.08/118.37 = { by axiom 8 (commutativity_of_join) } 118.08/118.37 join(meet(b, a), meet(a, join(meet(a, c), b))) 118.08/118.37 = { by axiom 3 (commutativity_of_meet) } 118.08/118.37 join(meet(a, b), meet(a, join(meet(a, c), b))) 118.08/118.37 = { by axiom 8 (commutativity_of_join) } 118.08/118.37 join(meet(a, b), meet(a, join(b, meet(a, c)))) 118.08/118.37 = { by lemma 61 } 118.08/118.37 join(meet(a, b), meet(a, join(meet(a, c), meet(a, b)))) 118.08/118.37 = { by axiom 8 (commutativity_of_join) } 118.08/118.37 join(meet(a, b), meet(a, join(meet(a, b), meet(a, c)))) 118.08/118.37 = { by lemma 15 } 118.08/118.37 join(meet(a, b), join(meet(a, c), meet(a, join(meet(a, b), meet(a, c))))) 118.08/118.37 = { by lemma 16 } 118.08/118.37 join(meet(a, b), meet(a, c)) 118.08/118.37 % SZS output end Proof 118.08/118.37 118.08/118.37 RESULT: Unsatisfiable (the axioms are contradictory). 118.16/118.38 EOF