0.12/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.12/0.12 % Command : parallel-twee %s --tstp --conditional-encoding if --smaller --drop-non-horn --give-up-on-saturation --explain-encoding --formal-proof 0.12/0.34 % Computer : n011.cluster.edu 0.12/0.34 % Model : x86_64 x86_64 0.12/0.34 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.12/0.34 % Memory : 8042.1875MB 0.12/0.34 % OS : Linux 3.10.0-693.el7.x86_64 0.12/0.34 % CPULimit : 1200 0.12/0.34 % WCLimit : 120 0.12/0.34 % DateTime : Tue Jul 13 11:44:40 EDT 2021 0.12/0.34 % CPUTime : 0.19/0.55 % SZS status Theorem 0.19/0.55 0.19/0.55 % SZS output start Proof 0.19/0.55 Take the following subset of the input axioms: 0.19/0.55 fof(axiom_1, axiom, ?[Y24]: ![X19]: ((id(X19, Y24) & r1(X19)) | (~r1(X19) & ~id(X19, Y24)))). 0.19/0.55 fof(axiom_1a, axiom, ![X1, X8]: ?[Y4]: (?[Y5]: (?[Y15]: (r2(X8, Y15) & r3(X1, Y15, Y5)) & id(Y5, Y4)) & ?[Y7]: (r2(Y7, Y4) & r3(X1, X8, Y7)))). 0.19/0.55 fof(axiom_2, axiom, ![X11]: ?[Y21]: ![X12]: ((id(X12, Y21) & r2(X11, X12)) | (~r2(X11, X12) & ~id(X12, Y21)))). 0.19/0.55 fof(axiom_5, axiom, ![X20]: id(X20, X20)). 0.19/0.55 fof(axiom_6, axiom, ![X21, X22]: (id(X22, X21) | ~id(X21, X22))). 0.19/0.55 fof(axiom_7a, axiom, ![X7, Y10]: (~r2(X7, Y10) | ![Y20]: (~id(Y20, Y10) | ~r1(Y20)))). 0.19/0.55 fof(axiom_8, axiom, ![X26, X27]: (~id(X26, X27) | ((~r1(X26) & ~r1(X27)) | (r1(X26) & r1(X27))))). 0.19/0.55 fof(infiniteNumbersid, conjecture, ![X1]: ?[Y2, Y1]: (?[Y3]: (id(Y3, Y2) & r3(X1, Y1, Y3)) & ![Y4]: (~r1(Y4) | ~id(Y1, Y4)))). 0.19/0.55 0.19/0.55 Now clausify the problem and encode Horn clauses using encoding 3 of 0.19/0.55 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.19/0.55 We repeatedly replace C & s=t => u=v by the two clauses: 0.19/0.55 fresh(y, y, x1...xn) = u 0.19/0.55 C => fresh(s, t, x1...xn) = v 0.19/0.55 where fresh is a fresh function symbol and x1..xn are the free 0.19/0.55 variables of u and v. 0.19/0.55 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.19/0.55 input problem has no model of domain size 1). 0.19/0.55 0.19/0.55 The encoding turns the above axioms into the following unit equations and goals: 0.19/0.55 0.19/0.55 Axiom 1 (axiom_5): id(X, X) = true2. 0.19/0.55 Axiom 2 (infiniteNumbersid_1): fresh(X, X, Y) = true2. 0.19/0.55 Axiom 3 (axiom_1_1): fresh21(X, X, Y) = true2. 0.19/0.55 Axiom 4 (axiom_8_1): fresh7(X, X, Y) = true2. 0.19/0.55 Axiom 5 (infiniteNumbersid): fresh3(X, X, Y) = true2. 0.19/0.55 Axiom 6 (axiom_1a_1): r3(X, Y, y7(X, Y)) = true2. 0.19/0.55 Axiom 7 (axiom_1_1): fresh21(r1(X), true2, X) = id(X, y24). 0.19/0.55 Axiom 8 (axiom_2): fresh20(X, X, Y, Z) = true2. 0.19/0.55 Axiom 9 (axiom_6): fresh13(X, X, Y, Z) = true2. 0.19/0.55 Axiom 10 (axiom_8_1): fresh8(X, X, Y, Z) = r1(Y). 0.19/0.55 Axiom 11 (axiom_6): fresh13(id(X, Y), true2, X, Y) = id(Y, X). 0.19/0.55 Axiom 12 (axiom_8_1): fresh8(r1(X), true2, Y, X) = fresh7(id(Y, X), true2, Y). 0.19/0.55 Axiom 13 (infiniteNumbersid): fresh4(X, X, Y, Z, W) = id(Z, y4(Z)). 0.19/0.55 Axiom 14 (infiniteNumbersid_1): fresh2(X, X, Y, Z, W) = r1(y4(Z)). 0.19/0.55 Axiom 15 (axiom_2): fresh20(id(X, y21(Y)), true2, Y, X) = r2(Y, X). 0.19/0.55 Axiom 16 (infiniteNumbersid): fresh4(r3(x1, X, Y), true2, Z, X, Y) = fresh3(id(Y, Z), true2, X). 0.19/0.55 Axiom 17 (infiniteNumbersid_1): fresh2(r3(x1, X, Y), true2, Z, X, Y) = fresh(id(Y, Z), true2, X). 0.19/0.55 0.19/0.56 Lemma 18: r1(X) = true2. 0.19/0.56 Proof: 0.19/0.56 r1(X) 0.19/0.56 = { by axiom 10 (axiom_8_1) R->L } 0.19/0.56 fresh8(true2, true2, X, y4(X)) 0.19/0.56 = { by axiom 2 (infiniteNumbersid_1) R->L } 0.19/0.56 fresh8(fresh(true2, true2, X), true2, X, y4(X)) 0.19/0.56 = { by axiom 1 (axiom_5) R->L } 0.19/0.56 fresh8(fresh(id(y7(x1, X), y7(x1, X)), true2, X), true2, X, y4(X)) 0.19/0.56 = { by axiom 17 (infiniteNumbersid_1) R->L } 0.19/0.56 fresh8(fresh2(r3(x1, X, y7(x1, X)), true2, y7(x1, X), X, y7(x1, X)), true2, X, y4(X)) 0.19/0.56 = { by axiom 6 (axiom_1a_1) } 0.19/0.56 fresh8(fresh2(true2, true2, y7(x1, X), X, y7(x1, X)), true2, X, y4(X)) 0.19/0.56 = { by axiom 14 (infiniteNumbersid_1) } 0.19/0.56 fresh8(r1(y4(X)), true2, X, y4(X)) 0.19/0.56 = { by axiom 12 (axiom_8_1) } 0.19/0.56 fresh7(id(X, y4(X)), true2, X) 0.19/0.56 = { by axiom 13 (infiniteNumbersid) R->L } 0.19/0.56 fresh7(fresh4(true2, true2, y7(x1, X), X, y7(x1, X)), true2, X) 0.19/0.56 = { by axiom 6 (axiom_1a_1) R->L } 0.19/0.56 fresh7(fresh4(r3(x1, X, y7(x1, X)), true2, y7(x1, X), X, y7(x1, X)), true2, X) 0.19/0.56 = { by axiom 16 (infiniteNumbersid) } 0.19/0.56 fresh7(fresh3(id(y7(x1, X), y7(x1, X)), true2, X), true2, X) 0.19/0.56 = { by axiom 1 (axiom_5) } 0.19/0.56 fresh7(fresh3(true2, true2, X), true2, X) 0.19/0.56 = { by axiom 5 (infiniteNumbersid) } 0.19/0.56 fresh7(true2, true2, X) 0.19/0.56 = { by axiom 4 (axiom_8_1) } 0.19/0.56 true2 0.19/0.56 0.19/0.56 Lemma 19: id(X, y24) = true2. 0.19/0.56 Proof: 0.19/0.56 id(X, y24) 0.19/0.56 = { by axiom 7 (axiom_1_1) R->L } 0.19/0.56 fresh21(r1(X), true2, X) 0.19/0.56 = { by lemma 18 } 0.19/0.56 fresh21(true2, true2, X) 0.19/0.56 = { by axiom 3 (axiom_1_1) } 0.19/0.56 true2 0.19/0.56 0.19/0.56 Goal 1 (axiom_7a): tuple(id(X, Y), r2(Z, Y), r1(X)) = tuple(true2, true2, true2). 0.19/0.56 The goal is true when: 0.19/0.56 X = X 0.19/0.56 Y = y24 0.19/0.56 Z = Y 0.19/0.56 0.19/0.56 Proof: 0.19/0.56 tuple(id(X, y24), r2(Y, y24), r1(X)) 0.19/0.56 = { by axiom 15 (axiom_2) R->L } 0.19/0.56 tuple(id(X, y24), fresh20(id(y24, y21(Y)), true2, Y, y24), r1(X)) 0.19/0.56 = { by axiom 11 (axiom_6) R->L } 0.19/0.56 tuple(id(X, y24), fresh20(fresh13(id(y21(Y), y24), true2, y21(Y), y24), true2, Y, y24), r1(X)) 0.19/0.56 = { by lemma 19 } 0.19/0.56 tuple(id(X, y24), fresh20(fresh13(true2, true2, y21(Y), y24), true2, Y, y24), r1(X)) 0.19/0.56 = { by axiom 9 (axiom_6) } 0.19/0.56 tuple(id(X, y24), fresh20(true2, true2, Y, y24), r1(X)) 0.19/0.56 = { by axiom 8 (axiom_2) } 0.19/0.56 tuple(id(X, y24), true2, r1(X)) 0.19/0.56 = { by lemma 19 } 0.19/0.56 tuple(true2, true2, r1(X)) 0.19/0.56 = { by lemma 18 } 0.19/0.56 tuple(true2, true2, true2) 0.19/0.56 % SZS output end Proof 0.19/0.56 0.19/0.56 RESULT: Theorem (the conjecture is true). 0.19/0.56 EOF