0.07/0.15 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.07/0.16 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.12/0.37 % Computer : n013.cluster.edu 0.12/0.37 % Model : x86_64 x86_64 0.12/0.37 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.12/0.37 % Memory : 8042.1875MB 0.12/0.37 % OS : Linux 3.10.0-693.el7.x86_64 0.12/0.37 % CPULimit : 180 0.12/0.37 % DateTime : Thu Aug 29 14:12:46 EDT 2019 0.12/0.37 % CPUTime : 131.05/131.33 % SZS status Unsatisfiable 131.05/131.33 131.05/131.34 % SZS output start Proof 131.05/131.34 Take the following subset of the input axioms: 131.16/131.47 fof(cn_1, axiom, ![X, Y, Z]: is_a_theorem(implies(implies(X, Y), implies(implies(Y, Z), implies(X, Z))))=true). 131.16/131.47 fof(cn_2, axiom, ![X]: is_a_theorem(implies(implies(not(X), X), X))=true). 131.16/131.47 fof(cn_3, axiom, ![X, Y]: is_a_theorem(implies(X, implies(not(X), Y)))=true). 131.16/131.47 fof(condensed_detachment, axiom, ![X, Y]: ifeq(is_a_theorem(implies(X, Y)), true, ifeq(is_a_theorem(X), true, is_a_theorem(Y), true), true)=true). 131.16/131.47 fof(ifeq_axiom, axiom, ![B, A, C]: B=ifeq(A, A, B, C)). 131.16/131.47 fof(prove_cn_54, negated_conjecture, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b)))!=true). 131.16/131.47 131.16/131.47 Now clausify the problem and encode Horn clauses using encoding 3 of 131.16/131.47 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 131.16/131.47 We repeatedly replace C & s=t => u=v by the two clauses: 131.16/131.47 fresh(y, y, x1...xn) = u 131.16/131.47 C => fresh(s, t, x1...xn) = v 131.16/131.47 where fresh is a fresh function symbol and x1..xn are the free 131.16/131.47 variables of u and v. 131.16/131.47 A predicate p(X) is encoded as p(X)=true (this is sound, because the 131.16/131.47 input problem has no model of domain size 1). 131.16/131.47 131.16/131.47 The encoding turns the above axioms into the following unit equations and goals: 131.16/131.47 131.16/131.47 Axiom 1 (cn_1): is_a_theorem(implies(implies(X, Y), implies(implies(Y, Z), implies(X, Z)))) = true. 131.16/131.47 Axiom 2 (cn_3): is_a_theorem(implies(X, implies(not(X), Y))) = true. 131.16/131.47 Axiom 3 (condensed_detachment): ifeq(is_a_theorem(implies(X, Y)), true, ifeq(is_a_theorem(X), true, is_a_theorem(Y), true), true) = true. 131.16/131.47 Axiom 4 (cn_2): is_a_theorem(implies(implies(not(X), X), X)) = true. 131.16/131.48 Axiom 5 (ifeq_axiom): X = ifeq(Y, Y, X, Z). 131.16/131.48 131.16/131.48 Lemma 6: ifeq(is_a_theorem(implies(X, Y)), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true) = true. 131.16/131.48 Proof: 131.16/131.48 ifeq(is_a_theorem(implies(X, Y)), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, ifeq(is_a_theorem(implies(X, Y)), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true), true) 131.16/131.48 = { by axiom 1 (cn_1) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, Y), implies(implies(Y, Z), implies(X, Z)))), true, ifeq(is_a_theorem(implies(X, Y)), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 7: is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))) = true. 131.16/131.48 Proof: 131.16/131.48 is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.48 ifeq(ifeq(is_a_theorem(implies(implies(implies(not(X), X), X), implies(implies(X, Y), implies(implies(not(X), X), Y)))), true, ifeq(is_a_theorem(implies(implies(not(X), X), X)), true, is_a_theorem(implies(implies(X, Y), implies(implies(not(X), X), Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))), true) 131.16/131.48 = { by axiom 1 (cn_1) } 131.16/131.48 ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(implies(not(X), X), X)), true, is_a_theorem(implies(implies(X, Y), implies(implies(not(X), X), Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))), true) 131.16/131.48 = { by axiom 4 (cn_2) } 131.16/131.48 ifeq(ifeq(true, true, ifeq(true, true, is_a_theorem(implies(implies(X, Y), implies(implies(not(X), X), Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(ifeq(true, true, is_a_theorem(implies(implies(X, Y), implies(implies(not(X), X), Y))), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, Y), implies(implies(not(X), X), Y))), true, is_a_theorem(implies(implies(implies(implies(not(X), X), Y), Z), implies(implies(X, Y), Z))), true) 131.16/131.48 = { by lemma 6 } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 8: ifeq(is_a_theorem(implies(implies(implies(X, Y), implies(Z, Y)), W)), true, is_a_theorem(implies(implies(Z, X), W)), true) = true. 131.16/131.48 Proof: 131.16/131.48 ifeq(is_a_theorem(implies(implies(implies(X, Y), implies(Z, Y)), W)), true, is_a_theorem(implies(implies(Z, X), W)), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, ifeq(is_a_theorem(implies(implies(implies(X, Y), implies(Z, Y)), W)), true, is_a_theorem(implies(implies(Z, X), W)), true), true) 131.16/131.48 = { by lemma 6 } 131.16/131.48 ifeq(ifeq(is_a_theorem(implies(implies(Z, X), implies(implies(X, Y), implies(Z, Y)))), true, is_a_theorem(implies(implies(implies(implies(X, Y), implies(Z, Y)), W), implies(implies(Z, X), W))), true), true, ifeq(is_a_theorem(implies(implies(implies(X, Y), implies(Z, Y)), W)), true, is_a_theorem(implies(implies(Z, X), W)), true), true) 131.16/131.48 = { by axiom 1 (cn_1) } 131.16/131.48 ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(implies(X, Y), implies(Z, Y)), W), implies(implies(Z, X), W))), true), true, ifeq(is_a_theorem(implies(implies(implies(X, Y), implies(Z, Y)), W)), true, is_a_theorem(implies(implies(Z, X), W)), true), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(implies(implies(X, Y), implies(Z, Y)), W), implies(implies(Z, X), W))), true, ifeq(is_a_theorem(implies(implies(implies(X, Y), implies(Z, Y)), W)), true, is_a_theorem(implies(implies(Z, X), W)), true), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 9: is_a_theorem(implies(implies(X, implies(not(Y), Y)), implies(implies(Y, Z), implies(X, Z)))) = true. 131.16/131.48 Proof: 131.16/131.48 is_a_theorem(implies(implies(X, implies(not(Y), Y)), implies(implies(Y, Z), implies(X, Z)))) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, is_a_theorem(implies(implies(X, implies(not(Y), Y)), implies(implies(Y, Z), implies(X, Z)))), true) 131.16/131.48 = { by lemma 7 } 131.16/131.48 ifeq(is_a_theorem(implies(implies(implies(implies(not(Y), Y), Z), implies(X, Z)), implies(implies(Y, Z), implies(X, Z)))), true, is_a_theorem(implies(implies(X, implies(not(Y), Y)), implies(implies(Y, Z), implies(X, Z)))), true) 131.16/131.48 = { by lemma 8 } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 10: is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))) = true. 131.16/131.48 Proof: 131.16/131.48 is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))), true) 131.16/131.48 = { by axiom 1 (cn_1) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, implies(not(X), Y)), implies(implies(implies(not(X), Y), Z), implies(X, Z)))), true, is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, implies(not(X), Y)), implies(implies(implies(not(X), Y), Z), implies(X, Z)))), true, ifeq(true, true, is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))), true), true) 131.16/131.48 = { by axiom 2 (cn_3) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, implies(not(X), Y)), implies(implies(implies(not(X), Y), Z), implies(X, Z)))), true, ifeq(is_a_theorem(implies(X, implies(not(X), Y))), true, is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))), true), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 11: ifeq(is_a_theorem(implies(implies(X, Y), Z)), true, is_a_theorem(implies(implies(implies(not(X), W), Y), Z)), true) = true. 131.16/131.48 Proof: 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, Y), Z)), true, is_a_theorem(implies(implies(implies(not(X), W), Y), Z)), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, ifeq(is_a_theorem(implies(implies(X, Y), Z)), true, is_a_theorem(implies(implies(implies(not(X), W), Y), Z)), true), true) 131.16/131.48 = { by lemma 6 } 131.16/131.48 ifeq(ifeq(is_a_theorem(implies(implies(implies(not(X), W), Y), implies(X, Y))), true, is_a_theorem(implies(implies(implies(X, Y), Z), implies(implies(implies(not(X), W), Y), Z))), true), true, ifeq(is_a_theorem(implies(implies(X, Y), Z)), true, is_a_theorem(implies(implies(implies(not(X), W), Y), Z)), true), true) 131.16/131.48 = { by lemma 10 } 131.16/131.48 ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(X, Y), Z), implies(implies(implies(not(X), W), Y), Z))), true), true, ifeq(is_a_theorem(implies(implies(X, Y), Z)), true, is_a_theorem(implies(implies(implies(not(X), W), Y), Z)), true), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(implies(X, Y), Z), implies(implies(implies(not(X), W), Y), Z))), true, ifeq(is_a_theorem(implies(implies(X, Y), Z)), true, is_a_theorem(implies(implies(implies(not(X), W), Y), Z)), true), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 12: ifeq(is_a_theorem(implies(implies(not(X), Y), Z)), true, is_a_theorem(implies(X, Z)), true) = true. 131.16/131.48 Proof: 131.16/131.48 ifeq(is_a_theorem(implies(implies(not(X), Y), Z)), true, is_a_theorem(implies(X, Z)), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, ifeq(is_a_theorem(implies(implies(not(X), Y), Z)), true, is_a_theorem(implies(X, Z)), true), true) 131.16/131.48 = { by lemma 10 } 131.16/131.48 ifeq(is_a_theorem(implies(implies(implies(not(X), Y), Z), implies(X, Z))), true, ifeq(is_a_theorem(implies(implies(not(X), Y), Z)), true, is_a_theorem(implies(X, Z)), true), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 13: is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))) = true. 131.16/131.48 Proof: 131.16/131.48 is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(true, true, is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))), true) 131.16/131.48 = { by lemma 8 } 131.16/131.48 ifeq(ifeq(is_a_theorem(implies(implies(implies(not(Z), X), implies(not(X), X)), implies(implies(X, Y), implies(Z, Y)))), true, is_a_theorem(implies(implies(not(X), not(Z)), implies(implies(X, Y), implies(Z, Y)))), true), true, is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(not(Z), X), implies(not(X), X)), implies(implies(X, Y), implies(Z, Y)))), true), true, is_a_theorem(implies(implies(not(X), not(Z)), implies(implies(X, Y), implies(Z, Y)))), true), true, is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))), true) 131.16/131.48 = { by lemma 9 } 131.16/131.48 ifeq(ifeq(ifeq(is_a_theorem(implies(implies(Z, implies(not(X), X)), implies(implies(X, Y), implies(Z, Y)))), true, is_a_theorem(implies(implies(implies(not(Z), X), implies(not(X), X)), implies(implies(X, Y), implies(Z, Y)))), true), true, is_a_theorem(implies(implies(not(X), not(Z)), implies(implies(X, Y), implies(Z, Y)))), true), true, is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))), true) 131.16/131.48 = { by lemma 11 } 131.16/131.48 ifeq(ifeq(true, true, is_a_theorem(implies(implies(not(X), not(Z)), implies(implies(X, Y), implies(Z, Y)))), true), true, is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(not(X), not(Z)), implies(implies(X, Y), implies(Z, Y)))), true, is_a_theorem(implies(X, implies(implies(X, Y), implies(Z, Y)))), true) 131.16/131.48 = { by lemma 12 } 131.16/131.48 true 131.16/131.48 131.16/131.48 Lemma 14: ifeq(is_a_theorem(implies(implies(X, X), Y)), true, is_a_theorem(Y), true) = true. 131.16/131.48 Proof: 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, X), Y)), true, is_a_theorem(Y), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, X), Y)), true, ifeq(true, true, is_a_theorem(Y), true), true) 131.16/131.48 = { by lemma 12 } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, X), Y)), true, ifeq(ifeq(is_a_theorem(implies(implies(not(X), X), X)), true, is_a_theorem(implies(X, X)), true), true, is_a_theorem(Y), true), true) 131.16/131.48 = { by axiom 4 (cn_2) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, X), Y)), true, ifeq(ifeq(true, true, is_a_theorem(implies(X, X)), true), true, is_a_theorem(Y), true), true) 131.16/131.48 = { by axiom 5 (ifeq_axiom) } 131.16/131.48 ifeq(is_a_theorem(implies(implies(X, X), Y)), true, ifeq(is_a_theorem(implies(X, X)), true, is_a_theorem(Y), true), true) 131.16/131.48 = { by axiom 3 (condensed_detachment) } 131.16/131.49 true 131.16/131.49 131.16/131.49 Lemma 15: is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))) = true. 131.16/131.49 Proof: 131.16/131.49 is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(true, true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 3 (condensed_detachment) } 131.16/131.49 ifeq(ifeq(is_a_theorem(implies(implies(not(implies(implies(not(X), X), X)), not(Z)), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true, ifeq(is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(not(implies(implies(not(X), X), X)), not(Z)), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by lemma 11 } 131.16/131.49 ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(Z, implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X))), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true, is_a_theorem(implies(implies(implies(not(Z), implies(implies(not(X), X), X)), implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X))), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(X), X), X)), not(Z)), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 1 (cn_1) } 131.16/131.49 ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(not(Z), implies(implies(not(X), X), X)), implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X))), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(X), X), X)), not(Z)), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(not(Z), implies(implies(not(X), X), X)), implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X))), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true, is_a_theorem(implies(implies(not(implies(implies(not(X), X), X)), not(Z)), implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by lemma 8 } 131.16/131.49 ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(ifeq(true, true, ifeq(ifeq(true, true, is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 4 (cn_2) } 131.16/131.49 ifeq(ifeq(true, true, ifeq(ifeq(is_a_theorem(implies(implies(not(X), X), X)), true, is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(ifeq(true, true, ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(implies(not(X), X), X)), true, is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 2 (cn_3) } 131.16/131.49 ifeq(ifeq(true, true, ifeq(ifeq(is_a_theorem(implies(implies(implies(not(X), X), X), implies(not(implies(implies(not(X), X), X)), not(Z)))), true, ifeq(is_a_theorem(implies(implies(not(X), X), X)), true, is_a_theorem(implies(not(implies(implies(not(X), X), X)), not(Z))), true), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 3 (condensed_detachment) } 131.16/131.49 ifeq(ifeq(true, true, ifeq(true, true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(true, true, ifeq(is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true), true) 131.16/131.49 = { by lemma 7 } 131.16/131.49 ifeq(is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y)), implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y)))), true, ifeq(is_a_theorem(implies(implies(implies(not(implies(implies(not(X), X), X)), implies(implies(not(X), X), X)), Y), implies(Z, Y))), true, is_a_theorem(implies(implies(implies(implies(not(X), X), X), Y), implies(Z, Y))), true), true) 131.16/131.49 = { by axiom 3 (condensed_detachment) } 131.16/131.49 true 131.16/131.49 131.16/131.49 Lemma 16: is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))) = true. 131.16/131.49 Proof: 131.16/131.49 is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(true, true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true) 131.16/131.49 = { by lemma 8 } 131.16/131.49 ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(not(Z), Z), Z), implies(implies(X, Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true, is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true) 131.16/131.49 = { by lemma 15 } 131.16/131.49 ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(true, true, ifeq(is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true), true) 131.16/131.49 = { by lemma 6 } 131.16/131.49 ifeq(ifeq(is_a_theorem(implies(X, implies(implies(X, Z), implies(not(Z), Z)))), true, is_a_theorem(implies(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z))), implies(X, implies(Y, implies(implies(X, Z), Z))))), true), true, ifeq(is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true), true) 131.16/131.49 = { by lemma 13 } 131.16/131.49 ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z))), implies(X, implies(Y, implies(implies(X, Z), Z))))), true), true, ifeq(is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(is_a_theorem(implies(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z))), implies(X, implies(Y, implies(implies(X, Z), Z))))), true, ifeq(is_a_theorem(implies(implies(implies(X, Z), implies(not(Z), Z)), implies(Y, implies(implies(X, Z), Z)))), true, is_a_theorem(implies(X, implies(Y, implies(implies(X, Z), Z)))), true), true) 131.16/131.49 = { by axiom 3 (condensed_detachment) } 131.16/131.49 true 131.16/131.49 131.16/131.49 Lemma 17: ifeq(is_a_theorem(implies(X, implies(not(Y), Y))), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true) = true. 131.16/131.49 Proof: 131.16/131.49 ifeq(is_a_theorem(implies(X, implies(not(Y), Y))), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(true, true, ifeq(is_a_theorem(implies(X, implies(not(Y), Y))), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true), true) 131.16/131.49 = { by lemma 9 } 131.16/131.49 ifeq(is_a_theorem(implies(implies(X, implies(not(Y), Y)), implies(implies(Y, Z), implies(X, Z)))), true, ifeq(is_a_theorem(implies(X, implies(not(Y), Y))), true, is_a_theorem(implies(implies(Y, Z), implies(X, Z))), true), true) 131.16/131.49 = { by axiom 3 (condensed_detachment) } 131.16/131.49 true 131.16/131.49 131.16/131.49 Lemma 18: is_a_theorem(implies(implies(implies(implies(X, Y), Y), Z), implies(X, Z))) = true. 131.16/131.49 Proof: 131.16/131.49 is_a_theorem(implies(implies(implies(implies(X, Y), Y), Z), implies(X, Z))) 131.16/131.49 = { by axiom 5 (ifeq_axiom) } 131.16/131.49 ifeq(true, true, is_a_theorem(implies(implies(implies(implies(X, Y), Y), Z), implies(X, Z))), true) 131.16/131.49 = { by lemma 16 } 131.16/131.49 ifeq(is_a_theorem(implies(X, implies(not(implies(implies(X, Y), Y)), implies(implies(X, Y), Y)))), true, is_a_theorem(implies(implies(implies(implies(X, Y), Y), Z), implies(X, Z))), true) 131.16/131.49 = { by lemma 17 } 131.35/131.64 true 131.35/131.64 131.35/131.64 Goal 1 (prove_cn_54): is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))) = true. 131.35/131.64 Proof: 131.35/131.64 is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(true, true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 3 (condensed_detachment) } 131.35/131.64 ifeq(ifeq(is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 3 (condensed_detachment) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a))), true, ifeq(is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 18 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 14 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 13 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 8 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), implies(not(a), a)), implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)))), true, is_a_theorem(implies(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)))), true), true, ifeq(is_a_theorem(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 9 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)))), true), true, ifeq(is_a_theorem(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)))), true, ifeq(is_a_theorem(implies(not(a), implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(a, a), implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a))), true), true), true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 3 (condensed_detachment) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(not(a), b), implies(implies(a, b), b)), a), a)), true, is_a_theorem(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), a), a)), true), true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 11 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 8 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 14 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))))), true, is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))))), true), true, is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 15 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(not(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))))), true, is_a_theorem(implies(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))))), true), true, is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by lemma 17 } 131.35/131.64 ifeq(ifeq(ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.64 = { by axiom 5 (ifeq_axiom) } 131.35/131.65 ifeq(ifeq(ifeq(ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true, is_a_theorem(implies(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by lemma 8 } 131.35/131.65 ifeq(ifeq(ifeq(ifeq(true, true, is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by axiom 5 (ifeq_axiom) } 131.35/131.65 ifeq(ifeq(ifeq(is_a_theorem(implies(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a), implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b))))), true, ifeq(is_a_theorem(implies(not(implies(implies(not(a), b), implies(implies(a, b), b))), a)), true, is_a_theorem(implies(implies(a, implies(implies(not(a), b), implies(implies(a, b), b))), implies(implies(not(a), b), implies(implies(a, b), b)))), true), true), true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by axiom 3 (condensed_detachment) } 131.35/131.65 ifeq(ifeq(true, true, ifeq(is_a_theorem(implies(a, implies(implies(not(a), b), implies(implies(a, b), b)))), true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by lemma 16 } 131.35/131.65 ifeq(ifeq(true, true, ifeq(true, true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by axiom 5 (ifeq_axiom) } 131.35/131.65 ifeq(ifeq(true, true, is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by axiom 5 (ifeq_axiom) } 131.35/131.65 ifeq(is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true) 131.35/131.65 = { by axiom 5 (ifeq_axiom) } 131.35/131.65 ifeq(true, true, ifeq(is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true), true) 131.35/131.65 = { by lemma 8 } 131.35/131.65 ifeq(ifeq(is_a_theorem(implies(implies(implies(implies(implies(a, b), b), b), implies(implies(not(a), b), b)), implies(implies(a, b), implies(implies(not(a), b), b)))), true, is_a_theorem(implies(implies(implies(not(a), b), implies(implies(a, b), b)), implies(implies(a, b), implies(implies(not(a), b), b)))), true), true, ifeq(is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true), true) 131.35/131.65 = { by lemma 18 } 131.35/131.65 ifeq(ifeq(true, true, is_a_theorem(implies(implies(implies(not(a), b), implies(implies(a, b), b)), implies(implies(a, b), implies(implies(not(a), b), b)))), true), true, ifeq(is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true), true) 131.35/131.65 = { by axiom 5 (ifeq_axiom) } 131.35/131.65 ifeq(is_a_theorem(implies(implies(implies(not(a), b), implies(implies(a, b), b)), implies(implies(a, b), implies(implies(not(a), b), b)))), true, ifeq(is_a_theorem(implies(implies(not(a), b), implies(implies(a, b), b))), true, is_a_theorem(implies(implies(a, b), implies(implies(not(a), b), b))), true), true) 131.35/131.65 = { by axiom 3 (condensed_detachment) } 131.35/131.65 true 131.35/131.65 % SZS output end Proof 131.35/131.65 131.35/131.65 RESULT: Unsatisfiable (the axioms are contradictory). 131.35/131.66 EOF