0.04/0.12 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.04/0.12 % Command : parallel-twee %s --tstp --conditional-encoding if --smaller --drop-non-horn --give-up-on-saturation --explain-encoding --formal-proof 0.12/0.33 % Computer : n016.cluster.edu 0.12/0.33 % Model : x86_64 x86_64 0.12/0.33 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.12/0.33 % Memory : 8042.1875MB 0.12/0.33 % OS : Linux 3.10.0-693.el7.x86_64 0.12/0.33 % CPULimit : 1200 0.12/0.33 % WCLimit : 120 0.12/0.33 % DateTime : Tue Jul 13 10:51:53 EDT 2021 0.12/0.33 % CPUTime : 0.19/0.38 % SZS status Theorem 0.19/0.38 0.19/0.38 % SZS output start Proof 0.19/0.38 Take the following subset of the input axioms: 0.19/0.39 fof(x2138, conjecture, ?[Y]: ![E]: ?[M]: ![W]: (big_s(M, W) => ![Z]: (big_f(W, Z) => big_d(Z, Y, E))) <= (?[X]: ![E]: ?[N]: ![W]: (big_d(W, X, E) <= big_s(N, W)) & (![E]: ?[D]: ![A, B]: (![Y, Z]: ((big_f(B, Z) & big_f(A, Y)) => big_d(Y, Z, E)) <= big_d(A, B, D)) & ![X]: ?[Y]: big_f(X, Y)))). 0.19/0.39 0.19/0.39 Now clausify the problem and encode Horn clauses using encoding 3 of 0.19/0.39 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 0.19/0.39 We repeatedly replace C & s=t => u=v by the two clauses: 0.19/0.39 fresh(y, y, x1...xn) = u 0.19/0.39 C => fresh(s, t, x1...xn) = v 0.19/0.39 where fresh is a fresh function symbol and x1..xn are the free 0.19/0.39 variables of u and v. 0.19/0.39 A predicate p(X) is encoded as p(X)=true (this is sound, because the 0.19/0.39 input problem has no model of domain size 1). 0.19/0.39 0.19/0.39 The encoding turns the above axioms into the following unit equations and goals: 0.19/0.39 0.19/0.39 Axiom 1 (x2138_1): big_f(X, y(X)) = true2. 0.19/0.39 Axiom 2 (x2138): big_s(X, w(Y, X)) = true2. 0.19/0.39 Axiom 3 (x2138_2): big_f(w(X, Y), z(X, Y)) = true2. 0.19/0.39 Axiom 4 (x2138_3): fresh(X, X, Y, Z) = true2. 0.19/0.39 Axiom 5 (x2138_4): fresh4(X, X, Y, Z, W) = true2. 0.19/0.39 Axiom 6 (x2138_3): fresh(big_s(n(X), Y), true2, X, Y) = big_d(Y, x, X). 0.19/0.39 Axiom 7 (x2138_4): fresh2(X, X, Y, Z, W, V) = big_d(W, V, Y). 0.19/0.39 Axiom 8 (x2138_4): fresh3(X, X, Y, Z, W, V, U) = fresh4(big_f(Z, V), true2, Y, V, U). 0.19/0.39 Axiom 9 (x2138_4): fresh3(big_d(X, Y, d(Z)), true2, Z, X, Y, W, V) = fresh2(big_f(Y, V), true2, Z, X, W, V). 0.19/0.39 0.19/0.39 Goal 1 (x2138_5): big_d(z(X, Y), X, e(X)) = true2. 0.19/0.39 The goal is true when: 0.19/0.39 X = y(x) 0.19/0.39 Y = n(d(e(y(x)))) 0.19/0.39 0.19/0.39 Proof: 0.19/0.39 big_d(z(y(x), n(d(e(y(x))))), y(x), e(y(x))) 0.19/0.39 = { by axiom 7 (x2138_4) R->L } 0.19/0.39 fresh2(true2, true2, e(y(x)), w(y(x), n(d(e(y(x))))), z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 1 (x2138_1) R->L } 0.19/0.39 fresh2(big_f(x, y(x)), true2, e(y(x)), w(y(x), n(d(e(y(x))))), z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 9 (x2138_4) R->L } 0.19/0.39 fresh3(big_d(w(y(x), n(d(e(y(x))))), x, d(e(y(x)))), true2, e(y(x)), w(y(x), n(d(e(y(x))))), x, z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 6 (x2138_3) R->L } 0.19/0.39 fresh3(fresh(big_s(n(d(e(y(x)))), w(y(x), n(d(e(y(x)))))), true2, d(e(y(x))), w(y(x), n(d(e(y(x)))))), true2, e(y(x)), w(y(x), n(d(e(y(x))))), x, z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 2 (x2138) } 0.19/0.39 fresh3(fresh(true2, true2, d(e(y(x))), w(y(x), n(d(e(y(x)))))), true2, e(y(x)), w(y(x), n(d(e(y(x))))), x, z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 4 (x2138_3) } 0.19/0.39 fresh3(true2, true2, e(y(x)), w(y(x), n(d(e(y(x))))), x, z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 8 (x2138_4) } 0.19/0.39 fresh4(big_f(w(y(x), n(d(e(y(x))))), z(y(x), n(d(e(y(x)))))), true2, e(y(x)), z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 3 (x2138_2) } 0.19/0.39 fresh4(true2, true2, e(y(x)), z(y(x), n(d(e(y(x))))), y(x)) 0.19/0.39 = { by axiom 5 (x2138_4) } 0.19/0.39 true2 0.19/0.39 % SZS output end Proof 0.19/0.39 0.19/0.39 RESULT: Theorem (the conjecture is true). 0.19/0.39 EOF