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 : n123.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 04:24:11 CDT 2018 0.03/0.23 % CPUTime : 0.07/0.44 % SZS status Theorem 0.07/0.44 0.07/0.44 % SZS output start Proof 0.07/0.44 Take the following subset of the input axioms: 0.07/0.44 fof(aSatz7_7, axiom, ![Xa, Xp]: s(Xa, s(Xa, Xp))=Xp). 0.07/0.44 fof(aSatz7_8, conjecture, 0.07/0.44 ![Xa, Xp, Xq, Xr]: (s(Xa, Xp)!=Xr | (Xr!=s(Xa, Xq) | Xp=Xq))). 0.07/0.44 0.07/0.44 Now clausify the problem and encode Horn clauses using encoding 3 of 0.07/0.44 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.07/0.44 We repeatedly replace C & s=t => u=v by the two clauses: 0.07/0.44 $$fresh(y, y, x1...xn) = u 0.07/0.44 C => $$fresh(s, t, x1...xn) = v 0.07/0.44 where $$fresh is a fresh function symbol and x1..xn are the free 0.07/0.44 variables of u and v. 0.07/0.44 A predicate p(X) is encoded as p(X)=$$true (this is sound, because the 0.07/0.44 input problem has no model of domain size 1). 0.07/0.44 0.07/0.44 The encoding turns the above axioms into the following unit equations and goals: 0.07/0.44 0.07/0.44 Axiom 212 (aSatz7_7): s(X, s(X, Y)) = Y. 0.07/0.44 Axiom 279 (aSatz7_8): s(sK2_aSatz7_8_Xa, sK4_aSatz7_8_Xp) = sK1_aSatz7_8_Xr. 0.07/0.44 Axiom 280 (aSatz7_8_1): sK1_aSatz7_8_Xr = s(sK2_aSatz7_8_Xa, sK3_aSatz7_8_Xq). 0.07/0.44 0.07/0.44 Goal 1 (aSatz7_8_2): sK4_aSatz7_8_Xp = sK3_aSatz7_8_Xq. 0.07/0.44 Proof: 0.07/0.44 sK4_aSatz7_8_Xp 0.07/0.44 = { by axiom 212 (aSatz7_7) } 0.07/0.44 s(sK2_aSatz7_8_Xa, s(sK2_aSatz7_8_Xa, sK4_aSatz7_8_Xp)) 0.07/0.44 = { by axiom 279 (aSatz7_8) } 0.07/0.44 s(sK2_aSatz7_8_Xa, sK1_aSatz7_8_Xr) 0.07/0.44 = { by axiom 280 (aSatz7_8_1) } 0.07/0.44 s(sK2_aSatz7_8_Xa, s(sK2_aSatz7_8_Xa, sK3_aSatz7_8_Xq)) 0.07/0.44 = { by axiom 212 (aSatz7_7) } 0.07/0.44 sK3_aSatz7_8_Xq 0.07/0.44 % SZS output end Proof 0.07/0.44 0.07/0.44 RESULT: Theorem (the conjecture is true). 0.07/0.45 EOF