0.07/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.07/0.13 % 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 : n005.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 13:57:33 EDT 2021 0.12/0.34 % CPUTime : 5.13/1.00 % SZS status Theorem 5.13/1.00 5.13/1.01 % SZS output start Proof 5.13/1.01 Take the following subset of the input axioms: 5.13/1.01 fof(aSatz7_15a, axiom, ![Xa, Xp, Xq, Xr]: (s_t(s(Xa, Xp), s(Xa, Xq), s(Xa, Xr)) | ~s_t(Xp, Xq, Xr))). 5.13/1.01 fof(aSatz7_15b, conjecture, ![Xa, Xp, Xq, Xr]: (~s_t(s(Xa, Xp), s(Xa, Xq), s(Xa, Xr)) | s_t(Xp, Xq, Xr))). 5.13/1.01 fof(aSatz7_7, axiom, ![Xa, Xp]: s(Xa, s(Xa, Xp))=Xp). 5.13/1.01 5.13/1.01 Now clausify the problem and encode Horn clauses using encoding 3 of 5.13/1.01 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 5.13/1.01 We repeatedly replace C & s=t => u=v by the two clauses: 5.13/1.01 fresh(y, y, x1...xn) = u 5.13/1.01 C => fresh(s, t, x1...xn) = v 5.13/1.01 where fresh is a fresh function symbol and x1..xn are the free 5.13/1.01 variables of u and v. 5.13/1.01 A predicate p(X) is encoded as p(X)=true (this is sound, because the 5.13/1.01 input problem has no model of domain size 1). 5.13/1.01 5.13/1.01 The encoding turns the above axioms into the following unit equations and goals: 5.13/1.01 5.13/1.01 Axiom 1 (aSatz7_7): s(X, s(X, Y)) = Y. 5.13/1.01 Axiom 2 (aSatz7_15a): fresh58(X, X, Y, Z, W, V) = true2. 5.13/1.01 Axiom 3 (aSatz7_15b): s_t(s(xa, xp), s(xa, xq), s(xa, xr)) = true2. 5.13/1.01 Axiom 4 (aSatz7_15a): fresh58(s_t(X, Y, Z), true2, X, Y, Z, W) = s_t(s(W, X), s(W, Y), s(W, Z)). 5.13/1.01 5.13/1.01 Goal 1 (aSatz7_15b_1): s_t(xp, xq, xr) = true2. 5.13/1.01 Proof: 5.13/1.01 s_t(xp, xq, xr) 5.13/1.01 = { by axiom 1 (aSatz7_7) R->L } 5.13/1.01 s_t(xp, xq, s(xa, s(xa, xr))) 5.13/1.01 = { by axiom 1 (aSatz7_7) R->L } 5.13/1.01 s_t(xp, s(xa, s(xa, xq)), s(xa, s(xa, xr))) 5.13/1.01 = { by axiom 1 (aSatz7_7) R->L } 5.13/1.01 s_t(s(xa, s(xa, xp)), s(xa, s(xa, xq)), s(xa, s(xa, xr))) 5.13/1.01 = { by axiom 4 (aSatz7_15a) R->L } 5.13/1.01 fresh58(s_t(s(xa, xp), s(xa, xq), s(xa, xr)), true2, s(xa, xp), s(xa, xq), s(xa, xr), xa) 5.13/1.01 = { by axiom 3 (aSatz7_15b) } 5.13/1.01 fresh58(true2, true2, s(xa, xp), s(xa, xq), s(xa, xr), xa) 5.13/1.01 = { by axiom 2 (aSatz7_15a) } 5.13/1.01 true2 5.13/1.01 % SZS output end Proof 5.13/1.01 5.13/1.01 RESULT: Theorem (the conjecture is true). 5.13/1.01 EOF