0.00/0.03 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.00/0.04 % Command : twee %s --tstp --casc --quiet --conditional-encoding if --smaller --drop-non-horn 0.03/0.23 % Computer : n135.star.cs.uiowa.edu 0.03/0.23 % Model : x86_64 x86_64 0.03/0.23 % CPU : Intel(R) Xeon(R) CPU E5-2609 0 @ 2.40GHz 0.03/0.23 % Memory : 32218.625MB 0.03/0.23 % OS : Linux 3.10.0-693.2.2.el7.x86_64 0.03/0.23 % CPULimit : 300 0.03/0.23 % DateTime : Sat Jul 14 05:53:09 CDT 2018 0.03/0.23 % CPUTime : 5.25/5.47 % SZS status Theorem 5.25/5.47 5.32/5.54 % SZS output start Proof 5.32/5.54 Take the following subset of the input axioms: 5.32/5.54 fof(goals_15, conjecture, 5.32/5.54 ![X17, X18]: 5.32/5.54 '==>'('==>'(X17, X18), X18)='==>'('==>'(X18, X17), X17)). 5.32/5.54 fof(sos_01, axiom, 5.32/5.54 ![A, B, C]: '+'('+'(A, B), C)='+'(A, '+'(B, C))). 5.32/5.54 fof(sos_02, axiom, ![A, B]: '+'(A, B)='+'(B, A)). 5.32/5.54 fof(sos_03, axiom, ![A]: A='+'(A, '0')). 5.32/5.54 fof(sos_04, axiom, ![A]: '>='(A, A)). 5.32/5.54 fof(sos_06, axiom, 5.32/5.54 ![X3, X4]: (('>='(X4, X3) & '>='(X3, X4)) => X4=X3)). 5.32/5.54 fof(sos_07, axiom, 5.32/5.54 ![X5, X6, X7]: 5.32/5.54 ('>='(X6, '==>'(X5, X7)) <=> '>='('+'(X5, X6), X7))). 5.32/5.54 fof(sos_08, axiom, ![A]: '>='(A, '0')). 5.32/5.54 fof(sos_09, axiom, 5.32/5.54 ![X8, X9, X10]: 5.32/5.54 ('>='(X8, X9) => '>='('+'(X8, X10), '+'(X9, X10)))). 5.32/5.54 fof(sos_12, axiom, 5.32/5.54 ![A, B]: '+'(B, '==>'(B, A))='+'(A, '==>'(A, B))). 5.32/5.54 fof(sos_13, axiom, ![A]: '==>'('==>'(A, '1'), '1')=A). 5.32/5.54 fof(sos_14, axiom, ![A]: '1'='+'(A, '1')). 5.32/5.54 5.32/5.54 Now clausify the problem and encode Horn clauses using encoding 3 of 5.32/5.54 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 5.32/5.54 We repeatedly replace C & s=t => u=v by the two clauses: 5.32/5.54 $$fresh(y, y, x1...xn) = u 5.32/5.54 C => $$fresh(s, t, x1...xn) = v 5.32/5.54 where $$fresh is a fresh function symbol and x1..xn are the free 5.32/5.54 variables of u and v. 5.32/5.54 A predicate p(X) is encoded as p(X)=$$true (this is sound, because the 5.32/5.54 input problem has no model of domain size 1). 5.32/5.54 5.32/5.54 The encoding turns the above axioms into the following unit equations and goals: 5.32/5.54 5.32/5.54 Axiom 3 (sos_06): $$fresh(X, X, Y, Z) = Y. 5.32/5.54 Axiom 4 (sos_06): $$fresh2(X, X, Y, Z) = Z. 5.32/5.54 Axiom 6 (sos_07_1): $$fresh4(X, X, Y, Z, W) = $$true. 5.32/5.54 Axiom 7 (sos_09): $$fresh8(X, X, Y, Z, W) = $$true. 5.32/5.54 Axiom 10 (sos_01): (X + Y) + Z = X + (Y + Z). 5.32/5.54 Axiom 11 (sos_04): X >= X = $$true. 5.32/5.54 Axiom 12 (sos_13): (X ==> 1) ==> 1 = X. 5.32/5.54 Axiom 13 (sos_08): X >= 0 = $$true. 5.32/5.54 Axiom 14 (sos_09): $$fresh8(X >= Y, $$true, X, Y, Z) = (X + Z) >= (Y + Z). 5.32/5.54 Axiom 17 (sos_14): 1 = X + 1. 5.32/5.54 Axiom 18 (sos_02): X + Y = Y + X. 5.32/5.54 Axiom 19 (sos_03): X = X + 0. 5.32/5.54 Axiom 20 (sos_06): $$fresh2(X >= Y, $$true, Y, X) = $$fresh(Y >= X, $$true, Y, X). 5.32/5.54 Axiom 21 (sos_07_1): $$fresh4((X + Y) >= Z, $$true, X, Y, Z) = Y >= (X ==> Z). 5.32/5.54 Axiom 24 (sos_12): X + (X ==> Y) = Y + (Y ==> X). 5.32/5.54 5.32/5.54 Lemma 25: 0 + X = X. 5.32/5.54 Proof: 5.32/5.54 0 + X 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 X + 0 5.32/5.54 = { by axiom 19 (sos_03) } 5.32/5.54 X 5.32/5.54 5.32/5.54 Lemma 26: (X + Y) >= X = $$true. 5.32/5.54 Proof: 5.32/5.54 (X + Y) >= X 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 (Y + X) >= X 5.32/5.54 = { by lemma 25 } 5.32/5.54 (Y + X) >= (0 + X) 5.32/5.54 = { by axiom 14 (sos_09) } 5.32/5.54 $$fresh8(Y >= 0, $$true, Y, 0, X) 5.32/5.54 = { by axiom 13 (sos_08) } 5.32/5.54 $$fresh8($$true, $$true, Y, 0, X) 5.32/5.54 = { by axiom 7 (sos_09) } 5.32/5.54 $$true 5.32/5.54 5.32/5.54 Lemma 27: X + (Y + Z) = Y + (X + Z). 5.32/5.54 Proof: 5.32/5.54 X + (Y + Z) 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 (Y + Z) + X 5.32/5.54 = { by axiom 10 (sos_01) } 5.32/5.54 Y + (Z + X) 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 Y + (X + Z) 5.32/5.54 5.32/5.54 Lemma 28: X >= (Y ==> (X + Y)) = $$true. 5.32/5.54 Proof: 5.32/5.54 X >= (Y ==> (X + Y)) 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 X >= (Y ==> (Y + X)) 5.32/5.54 = { by axiom 21 (sos_07_1) } 5.32/5.54 $$fresh4((Y + X) >= (Y + X), $$true, Y, X, Y + X) 5.32/5.54 = { by axiom 11 (sos_04) } 5.32/5.54 $$fresh4($$true, $$true, Y, X, Y + X) 5.32/5.54 = { by axiom 6 (sos_07_1) } 5.32/5.54 $$true 5.32/5.54 5.32/5.54 Lemma 29: X + (Z + (X ==> Y)) = Y + ((Y ==> X) + Z). 5.32/5.54 Proof: 5.32/5.54 X + (Z + (X ==> Y)) 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 X + ((X ==> Y) + Z) 5.32/5.54 = { by axiom 10 (sos_01) } 5.32/5.54 (X + (X ==> Y)) + Z 5.32/5.54 = { by axiom 24 (sos_12) } 5.32/5.54 (Y + (Y ==> X)) + Z 5.32/5.54 = { by axiom 10 (sos_01) } 5.32/5.54 Y + ((Y ==> X) + Z) 5.32/5.54 5.32/5.54 Lemma 30: X + ((X ==> 1) + Y) = 1. 5.32/5.54 Proof: 5.32/5.54 X + ((X ==> 1) + Y) 5.32/5.54 = { by lemma 29 } 5.32/5.54 1 + (Y + (1 ==> X)) 5.32/5.54 = { by axiom 18 (sos_02) } 5.32/5.54 (Y + (1 ==> X)) + 1 5.32/5.54 = { by axiom 17 (sos_14) } 5.32/5.54 1 5.32/5.54 5.32/5.54 Lemma 31: Y + (Z + (Z ==> X)) = X + (Y + (X ==> Z)). 5.32/5.54 Proof: 5.32/5.54 Y + (Z + (Z ==> X)) 5.32/5.54 = { by axiom 24 (sos_12) } 5.32/5.54 Y + (X + (X ==> Z)) 5.32/5.54 = { by lemma 27 } 5.32/5.54 X + (Y + (X ==> Z)) 5.32/5.54 5.32/5.54 Lemma 32: X ==> (Y ==> (X + Y)) = 0. 5.32/5.54 Proof: 5.32/5.54 X ==> (Y ==> (X + Y)) 5.32/5.54 = { by axiom 3 (sos_06) } 5.32/5.54 $$fresh($$true, $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by axiom 13 (sos_08) } 5.32/5.54 $$fresh((X ==> (Y ==> (X + Y))) >= 0, $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by axiom 20 (sos_06) } 5.32/5.54 $$fresh2(0 >= (X ==> (Y ==> (X + Y))), $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by axiom 21 (sos_07_1) } 5.32/5.54 $$fresh2($$fresh4((X + 0) >= (Y ==> (X + Y)), $$true, X, 0, Y ==> (X + Y)), $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by axiom 19 (sos_03) } 5.32/5.54 $$fresh2($$fresh4(X >= (Y ==> (X + Y)), $$true, X, 0, Y ==> (X + Y)), $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by lemma 28 } 5.32/5.54 $$fresh2($$fresh4($$true, $$true, X, 0, Y ==> (X + Y)), $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by axiom 6 (sos_07_1) } 5.32/5.54 $$fresh2($$true, $$true, X ==> (Y ==> (X + Y)), 0) 5.32/5.54 = { by axiom 4 (sos_06) } 5.32/5.55 0 5.32/5.55 5.32/5.55 Lemma 33: (X ==> (Y ==> 1)) >= (Y ==> (X ==> 1)) = $$true. 5.32/5.55 Proof: 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> 1)) 5.32/5.55 = { by lemma 30 } 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> (Y + ((Y ==> 1) + ((Y ==> 1) ==> X))))) 5.32/5.55 = { by axiom 24 (sos_12) } 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> (Y + (X + (X ==> (Y ==> 1)))))) 5.32/5.55 = { by axiom 10 (sos_01) } 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> ((Y + X) + (X ==> (Y ==> 1))))) 5.32/5.55 = { by axiom 18 (sos_02) } 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> ((X ==> (Y ==> 1)) + (Y + X)))) 5.32/5.55 = { by lemma 27 } 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> (Y + ((X ==> (Y ==> 1)) + X)))) 5.32/5.55 = { by axiom 10 (sos_01) } 5.32/5.55 (X ==> (Y ==> 1)) >= (Y ==> (X ==> ((Y + (X ==> (Y ==> 1))) + X))) 5.32/5.55 = { by axiom 21 (sos_07_1) } 5.32/5.55 $$fresh4((Y + (X ==> (Y ==> 1))) >= (X ==> ((Y + (X ==> (Y ==> 1))) + X)), $$true, Y, X ==> (Y ==> 1), X ==> ((Y + (X ==> (Y ==> 1))) + X)) 5.32/5.55 = { by lemma 28 } 5.32/5.55 $$fresh4($$true, $$true, Y, X ==> (Y ==> 1), X ==> ((Y + (X ==> (Y ==> 1))) + X)) 5.32/5.55 = { by axiom 6 (sos_07_1) } 5.32/5.55 $$true 5.32/5.55 5.32/5.55 Lemma 34: X ==> (Y ==> 1) = Y ==> (X ==> 1). 5.32/5.55 Proof: 5.32/5.55 X ==> (Y ==> 1) 5.32/5.55 = { by axiom 3 (sos_06) } 5.32/5.55 $$fresh($$true, $$true, X ==> (Y ==> 1), Y ==> (X ==> 1)) 5.32/5.55 = { by lemma 33 } 5.32/5.55 $$fresh((X ==> (Y ==> 1)) >= (Y ==> (X ==> 1)), $$true, X ==> (Y ==> 1), Y ==> (X ==> 1)) 5.32/5.55 = { by axiom 20 (sos_06) } 5.32/5.55 $$fresh2((Y ==> (X ==> 1)) >= (X ==> (Y ==> 1)), $$true, X ==> (Y ==> 1), Y ==> (X ==> 1)) 5.32/5.55 = { by lemma 33 } 5.32/5.55 $$fresh2($$true, $$true, X ==> (Y ==> 1), Y ==> (X ==> 1)) 5.32/5.55 = { by axiom 4 (sos_06) } 5.32/5.55 Y ==> (X ==> 1) 5.32/5.55 5.32/5.55 Lemma 35: (X ==> 1) ==> (Y ==> 1) = Y ==> X. 5.32/5.55 Proof: 5.32/5.55 (X ==> 1) ==> (Y ==> 1) 5.32/5.55 = { by lemma 34 } 5.32/5.55 Y ==> ((X ==> 1) ==> 1) 5.32/5.55 = { by axiom 12 (sos_13) } 5.32/5.55 Y ==> X 5.32/5.55 5.32/5.55 Lemma 36: (X ==> (Y ==> Z)) >= (Y ==> (X ==> Z)) = $$true. 5.32/5.55 Proof: 5.32/5.55 (X ==> (Y ==> Z)) >= (Y ==> (X ==> Z)) 5.32/5.55 = { by axiom 21 (sos_07_1) } 5.32/5.55 $$fresh4((Y + (X ==> (Y ==> Z))) >= (X ==> Z), $$true, Y, X ==> (Y ==> Z), X ==> Z) 5.32/5.55 = { by axiom 21 (sos_07_1) } 5.32/5.55 $$fresh4($$fresh4((X + (Y + (X ==> (Y ==> Z)))) >= Z, $$true, X, Y + (X ==> (Y ==> Z)), Z), $$true, Y, X ==> (Y ==> Z), X ==> Z) 5.32/5.55 = { by lemma 31 } 5.32/5.55 $$fresh4($$fresh4((Y + ((Y ==> Z) + ((Y ==> Z) ==> X))) >= Z, $$true, X, Y + (X ==> (Y ==> Z)), Z), $$true, Y, X ==> (Y ==> Z), X ==> Z) 5.32/5.55 = { by lemma 29 } 5.32/5.55 $$fresh4($$fresh4((Z + (((Y ==> Z) ==> X) + (Z ==> Y))) >= Z, $$true, X, Y + (X ==> (Y ==> Z)), Z), $$true, Y, X ==> (Y ==> Z), X ==> Z) 5.32/5.55 = { by lemma 26 } 5.32/5.55 $$fresh4($$fresh4($$true, $$true, X, Y + (X ==> (Y ==> Z)), Z), $$true, Y, X ==> (Y ==> Z), X ==> Z) 5.32/5.55 = { by axiom 6 (sos_07_1) } 5.32/5.55 $$fresh4($$true, $$true, Y, X ==> (Y ==> Z), X ==> Z) 5.32/5.55 = { by axiom 6 (sos_07_1) } 5.32/5.55 $$true 5.32/5.55 5.32/5.55 Lemma 37: X ==> (Y ==> Z) = Y ==> (X ==> Z). 5.32/5.55 Proof: 5.32/5.55 X ==> (Y ==> Z) 5.32/5.55 = { by axiom 3 (sos_06) } 5.32/5.55 $$fresh($$true, $$true, X ==> (Y ==> Z), Y ==> (X ==> Z)) 5.32/5.55 = { by lemma 36 } 5.32/5.55 $$fresh((X ==> (Y ==> Z)) >= (Y ==> (X ==> Z)), $$true, X ==> (Y ==> Z), Y ==> (X ==> Z)) 5.32/5.55 = { by axiom 20 (sos_06) } 5.32/5.55 $$fresh2((Y ==> (X ==> Z)) >= (X ==> (Y ==> Z)), $$true, X ==> (Y ==> Z), Y ==> (X ==> Z)) 5.32/5.55 = { by lemma 36 } 5.32/5.55 $$fresh2($$true, $$true, X ==> (Y ==> Z), Y ==> (X ==> Z)) 5.32/5.55 = { by axiom 4 (sos_06) } 5.32/5.55 Y ==> (X ==> Z) 5.32/5.55 5.32/5.55 Lemma 38: X ==> (Y ==> (X + Y)) = 0. 5.32/5.55 Proof: 5.32/5.55 X ==> (Y ==> (X + Y)) 5.32/5.55 = { by lemma 37 } 5.32/5.55 Y ==> (X ==> (X + Y)) 5.32/5.55 = { by axiom 18 (sos_02) } 5.32/5.55 Y ==> (X ==> (Y + X)) 5.32/5.55 = { by lemma 32 } 5.32/5.55 0 5.32/5.55 5.32/5.55 Lemma 39: ((X ==> Z) ==> 1) ==> Y = X ==> ((Y ==> 1) ==> Z). 5.32/5.55 Proof: 5.32/5.55 ((X ==> Z) ==> 1) ==> Y 5.32/5.55 = { by axiom 12 (sos_13) } 5.32/5.55 ((X ==> Z) ==> 1) ==> ((Y ==> 1) ==> 1) 5.32/5.55 = { by lemma 35 } 5.32/5.55 (Y ==> 1) ==> (X ==> Z) 5.32/5.55 = { by lemma 37 } 5.40/5.63 X ==> ((Y ==> 1) ==> Z) 5.40/5.63 5.40/5.63 Lemma 40: (X + Y) ==> 1 = X ==> (Y ==> 1). 5.40/5.63 Proof: 5.40/5.63 (X + Y) ==> 1 5.40/5.63 = { by lemma 25 } 5.40/5.63 (0 + (X + Y)) ==> 1 5.40/5.63 = { by lemma 27 } 5.40/5.63 (X + (0 + Y)) ==> 1 5.40/5.63 = { by axiom 18 (sos_02) } 5.40/5.63 (X + (Y + 0)) ==> 1 5.40/5.63 = { by lemma 27 } 5.40/5.63 (Y + (X + 0)) ==> 1 5.40/5.63 = { by axiom 4 (sos_06) } 5.40/5.63 (Y + (X + $$fresh2($$true, $$true, 0 ==> 0, 0))) ==> 1 5.40/5.63 = { by lemma 28 } 5.40/5.63 (Y + (X + $$fresh2(0 >= (0 ==> (0 + 0)), $$true, 0 ==> 0, 0))) ==> 1 5.40/5.63 = { by axiom 19 (sos_03) } 5.40/5.63 (Y + (X + $$fresh2(0 >= (0 ==> 0), $$true, 0 ==> 0, 0))) ==> 1 5.40/5.63 = { by axiom 20 (sos_06) } 5.40/5.63 (Y + (X + $$fresh((0 ==> 0) >= 0, $$true, 0 ==> 0, 0))) ==> 1 5.40/5.63 = { by lemma 25 } 5.40/5.63 (Y + (X + $$fresh((0 + (0 ==> 0)) >= 0, $$true, 0 ==> 0, 0))) ==> 1 5.40/5.63 = { by lemma 26 } 5.40/5.63 (Y + (X + $$fresh($$true, $$true, 0 ==> 0, 0))) ==> 1 5.40/5.63 = { by axiom 3 (sos_06) } 5.40/5.63 (Y + (X + (0 ==> 0))) ==> 1 5.40/5.63 = { by lemma 38 } 5.40/5.63 (Y + (X + ((Y ==> (X ==> (Y + X))) ==> 0))) ==> 1 5.40/5.63 = { by lemma 35 } 5.40/5.63 (Y + (X + ((Y ==> (((Y + X) ==> 1) ==> (X ==> 1))) ==> 0))) ==> 1 5.40/5.63 = { by lemma 39 } 5.40/5.63 (Y + (X + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by lemma 25 } 5.40/5.63 (Y + (X + (0 + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0)))) ==> 1 5.40/5.63 = { by axiom 10 (sos_01) } 5.40/5.63 ((Y + X) + (0 + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by lemma 32 } 5.40/5.63 ((Y + X) + (((Y + X) ==> ((Y ==> (X ==> 1)) ==> ((Y + X) + (Y ==> (X ==> 1))))) + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by axiom 10 (sos_01) } 5.40/5.63 ((Y + X) + (((Y + X) ==> ((Y ==> (X ==> 1)) ==> (Y + (X + (Y ==> (X ==> 1)))))) + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by lemma 31 } 5.40/5.63 ((Y + X) + (((Y + X) ==> ((Y ==> (X ==> 1)) ==> (X + ((X ==> 1) + ((X ==> 1) ==> Y))))) + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by lemma 30 } 5.40/5.63 ((Y + X) + (((Y + X) ==> ((Y ==> (X ==> 1)) ==> 1)) + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by axiom 18 (sos_02) } 5.40/5.63 ((Y + X) + (((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0) + ((Y + X) ==> ((Y ==> (X ==> 1)) ==> 1)))) ==> 1 5.40/5.63 = { by lemma 29 } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) + ((((Y ==> (X ==> 1)) ==> 1) ==> (Y + X)) ==> 0))) ==> 1 5.40/5.63 = { by axiom 24 (sos_12) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + (0 ==> (((Y ==> (X ==> 1)) ==> 1) ==> (Y + X))))) ==> 1 5.40/5.63 = { by lemma 39 } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + (0 ==> (Y ==> (((Y + X) ==> 1) ==> (X ==> 1)))))) ==> 1 5.40/5.63 = { by lemma 35 } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + (0 ==> (Y ==> (X ==> (Y + X)))))) ==> 1 5.40/5.63 = { by lemma 38 } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + (0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 4 (sos_06) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + $$fresh2($$true, $$true, 0, 0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 13 (sos_08) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + $$fresh2((0 ==> 0) >= 0, $$true, 0, 0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 20 (sos_06) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + $$fresh(0 >= (0 ==> 0), $$true, 0, 0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 21 (sos_07_1) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + $$fresh($$fresh4((0 + 0) >= 0, $$true, 0, 0, 0), $$true, 0, 0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 13 (sos_08) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + $$fresh($$fresh4($$true, $$true, 0, 0, 0), $$true, 0, 0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 6 (sos_07_1) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + $$fresh($$true, $$true, 0, 0 ==> 0))) ==> 1 5.40/5.63 = { by axiom 3 (sos_06) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + (0 + 0)) ==> 1 5.40/5.63 = { by axiom 19 (sos_03) } 5.40/5.63 (((Y ==> (X ==> 1)) ==> 1) + 0) ==> 1 5.40/5.63 = { by axiom 18 (sos_02) } 5.40/5.63 (0 + ((Y ==> (X ==> 1)) ==> 1)) ==> 1 5.40/5.63 = { by lemma 34 } 5.40/5.63 (0 + ((X ==> (Y ==> 1)) ==> 1)) ==> 1 5.40/5.63 = { by lemma 25 } 5.40/5.63 ((X ==> (Y ==> 1)) ==> 1) ==> 1 5.40/5.63 = { by axiom 12 (sos_13) } 5.40/5.63 X ==> (Y ==> 1) 5.40/5.63 5.40/5.63 Goal 1 (goals_15): (sK2_goals_15_X17 ==> sK1_goals_15_X18) ==> sK1_goals_15_X18 = (sK1_goals_15_X18 ==> sK2_goals_15_X17) ==> sK2_goals_15_X17. 5.40/5.63 Proof: 5.40/5.63 (sK2_goals_15_X17 ==> sK1_goals_15_X18) ==> sK1_goals_15_X18 5.40/5.63 = { by axiom 12 (sos_13) } 5.40/5.63 (sK2_goals_15_X17 ==> sK1_goals_15_X18) ==> ((sK1_goals_15_X18 ==> 1) ==> 1) 5.40/5.63 = { by lemma 40 } 5.40/5.63 ((sK2_goals_15_X17 ==> sK1_goals_15_X18) + (sK1_goals_15_X18 ==> 1)) ==> 1 5.40/5.63 = { by axiom 18 (sos_02) } 5.40/5.63 ((sK1_goals_15_X18 ==> 1) + (sK2_goals_15_X17 ==> sK1_goals_15_X18)) ==> 1 5.40/5.63 = { by lemma 35 } 5.40/5.63 ((sK1_goals_15_X18 ==> 1) + ((sK1_goals_15_X18 ==> 1) ==> (sK2_goals_15_X17 ==> 1))) ==> 1 5.40/5.63 = { by axiom 24 (sos_12) } 5.40/5.63 ((sK2_goals_15_X17 ==> 1) + ((sK2_goals_15_X17 ==> 1) ==> (sK1_goals_15_X18 ==> 1))) ==> 1 5.40/5.63 = { by lemma 35 } 5.40/5.63 ((sK2_goals_15_X17 ==> 1) + (sK1_goals_15_X18 ==> sK2_goals_15_X17)) ==> 1 5.40/5.63 = { by lemma 40 } 5.40/5.63 (sK2_goals_15_X17 ==> 1) ==> ((sK1_goals_15_X18 ==> sK2_goals_15_X17) ==> 1) 5.40/5.63 = { by lemma 35 } 5.40/5.63 (sK1_goals_15_X18 ==> sK2_goals_15_X17) ==> sK2_goals_15_X17 5.40/5.63 % SZS output end Proof 5.40/5.63 5.40/5.63 RESULT: Theorem (the conjecture is true). 5.40/5.64 EOF