TSTP Solution File: LCL043-1 by Twee---2.4.2
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% File : Twee---2.4.2
% Problem : LCL043-1 : TPTP v8.1.2. Released v1.0.0.
% Transfm : none
% Format : tptp:raw
% Command : parallel-twee %s --tstp --conditional-encoding if --smaller --drop-non-horn --give-up-on-saturation --explain-encoding --formal-proof
% Computer : n029.cluster.edu
% Model : x86_64 x86_64
% CPU : Intel(R) Xeon(R) CPU E5-2620 v4 2.10GHz
% Memory : 8042.1875MB
% OS : Linux 3.10.0-693.el7.x86_64
% CPULimit : 300s
% WCLimit : 300s
% DateTime : Thu Aug 31 08:17:09 EDT 2023
% Result : Unsatisfiable 0.20s 0.40s
% Output : Proof 0.20s
% Verified :
% SZS Type : -
% Comments :
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%----WARNING: Could not form TPTP format derivation
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%----ORIGINAL SYSTEM OUTPUT
% 0.00/0.13 % Problem : LCL043-1 : TPTP v8.1.2. Released v1.0.0.
% 0.13/0.14 % Command : parallel-twee %s --tstp --conditional-encoding if --smaller --drop-non-horn --give-up-on-saturation --explain-encoding --formal-proof
% 0.13/0.35 % Computer : n029.cluster.edu
% 0.13/0.35 % Model : x86_64 x86_64
% 0.13/0.35 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
% 0.13/0.35 % Memory : 8042.1875MB
% 0.13/0.35 % OS : Linux 3.10.0-693.el7.x86_64
% 0.13/0.35 % CPULimit : 300
% 0.13/0.35 % WCLimit : 300
% 0.13/0.35 % DateTime : Fri Aug 25 07:36:53 EDT 2023
% 0.13/0.35 % CPUTime :
% 0.20/0.40 Command-line arguments: --no-flatten-goal
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% 0.20/0.40 % SZS status Unsatisfiable
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% 0.20/0.40 % SZS output start Proof
% 0.20/0.40 Take the following subset of the input axioms:
% 0.20/0.40 fof(cn_18, axiom, ![X, Y]: is_a_theorem(implies(X, implies(Y, X)))).
% 0.20/0.40 fof(cn_3, axiom, ![X2, Y2]: is_a_theorem(implies(X2, implies(not(X2), Y2)))).
% 0.20/0.40 fof(cn_54, axiom, ![X2, Y2]: is_a_theorem(implies(implies(X2, Y2), implies(implies(not(X2), Y2), Y2)))).
% 0.20/0.40 fof(condensed_detachment, axiom, ![X2, Y2]: (~is_a_theorem(implies(X2, Y2)) | (~is_a_theorem(X2) | is_a_theorem(Y2)))).
% 0.20/0.40 fof(prove_cn_39, negated_conjecture, ~is_a_theorem(implies(not(not(a)), a))).
% 0.20/0.40
% 0.20/0.40 Now clausify the problem and encode Horn clauses using encoding 3 of
% 0.20/0.40 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf.
% 0.20/0.40 We repeatedly replace C & s=t => u=v by the two clauses:
% 0.20/0.40 fresh(y, y, x1...xn) = u
% 0.20/0.40 C => fresh(s, t, x1...xn) = v
% 0.20/0.40 where fresh is a fresh function symbol and x1..xn are the free
% 0.20/0.40 variables of u and v.
% 0.20/0.40 A predicate p(X) is encoded as p(X)=true (this is sound, because the
% 0.20/0.40 input problem has no model of domain size 1).
% 0.20/0.40
% 0.20/0.40 The encoding turns the above axioms into the following unit equations and goals:
% 0.20/0.40
% 0.20/0.40 Axiom 1 (condensed_detachment): fresh2(X, X, Y) = true.
% 0.20/0.41 Axiom 2 (condensed_detachment): fresh(X, X, Y, Z) = is_a_theorem(Z).
% 0.20/0.41 Axiom 3 (cn_18): is_a_theorem(implies(X, implies(Y, X))) = true.
% 0.20/0.41 Axiom 4 (cn_3): is_a_theorem(implies(X, implies(not(X), Y))) = true.
% 0.20/0.41 Axiom 5 (condensed_detachment): fresh(is_a_theorem(implies(X, Y)), true, X, Y) = fresh2(is_a_theorem(X), true, Y).
% 0.20/0.41 Axiom 6 (cn_54): is_a_theorem(implies(implies(X, Y), implies(implies(not(X), Y), Y))) = true.
% 0.20/0.41
% 0.20/0.41 Goal 1 (prove_cn_39): is_a_theorem(implies(not(not(a)), a)) = true.
% 0.20/0.41 Proof:
% 0.20/0.41 is_a_theorem(implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 2 (condensed_detachment) R->L }
% 0.20/0.41 fresh(true, true, implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 1 (condensed_detachment) R->L }
% 0.20/0.41 fresh(fresh2(true, true, implies(implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))), true, implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 3 (cn_18) R->L }
% 0.20/0.41 fresh(fresh2(is_a_theorem(implies(a, implies(not(not(a)), a))), true, implies(implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))), true, implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 5 (condensed_detachment) R->L }
% 0.20/0.41 fresh(fresh(is_a_theorem(implies(implies(a, implies(not(not(a)), a)), implies(implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a)))), true, implies(a, implies(not(not(a)), a)), implies(implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))), true, implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 6 (cn_54) }
% 0.20/0.41 fresh(fresh(true, true, implies(a, implies(not(not(a)), a)), implies(implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))), true, implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 2 (condensed_detachment) }
% 0.20/0.41 fresh(is_a_theorem(implies(implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))), true, implies(not(a), implies(not(not(a)), a)), implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 5 (condensed_detachment) }
% 0.20/0.41 fresh2(is_a_theorem(implies(not(a), implies(not(not(a)), a))), true, implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 4 (cn_3) }
% 0.20/0.41 fresh2(true, true, implies(not(not(a)), a))
% 0.20/0.41 = { by axiom 1 (condensed_detachment) }
% 0.20/0.41 true
% 0.20/0.41 % SZS output end Proof
% 0.20/0.41
% 0.20/0.41 RESULT: Unsatisfiable (the axioms are contradictory).
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