0.03/0.11 % Problem : theBenchmark.p : TPTP v0.0.0. Released v0.0.0. 0.03/0.12 % Command : twee %s --tstp --casc --quiet --explain-encoding --conditional-encoding if --smaller --drop-non-horn 0.12/0.31 % Computer : n004.cluster.edu 0.12/0.31 % Model : x86_64 x86_64 0.12/0.31 % CPU : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz 0.12/0.31 % Memory : 8042.1875MB 0.12/0.31 % OS : Linux 3.10.0-693.el7.x86_64 0.12/0.32 % CPULimit : 180 0.12/0.32 % DateTime : Thu Aug 29 09:06:38 EDT 2019 0.12/0.32 % CPUTime : 5.85/6.04 % SZS status Unsatisfiable 5.85/6.04 5.85/6.04 % SZS output start Proof 5.85/6.04 Take the following subset of the input axioms: 5.85/6.04 fof(associativity_of_glb, axiom, ![X, Y, Z]: greatest_lower_bound(X, greatest_lower_bound(Y, Z))=greatest_lower_bound(greatest_lower_bound(X, Y), Z)). 5.85/6.04 fof(glb_absorbtion, axiom, ![X, Y]: greatest_lower_bound(X, least_upper_bound(X, Y))=X). 5.85/6.04 fof(lub_absorbtion, axiom, ![X, Y]: X=least_upper_bound(X, greatest_lower_bound(X, Y))). 5.85/6.04 fof(monotony_glb1, axiom, ![X, Y, Z]: multiply(X, greatest_lower_bound(Y, Z))=greatest_lower_bound(multiply(X, Y), multiply(X, Z))). 5.85/6.04 fof(monotony_glb2, axiom, ![X, Y, Z]: greatest_lower_bound(multiply(Y, X), multiply(Z, X))=multiply(greatest_lower_bound(Y, Z), X)). 5.85/6.04 fof(p03d_1, hypothesis, b=least_upper_bound(a, b)). 5.85/6.04 fof(p03d_2, hypothesis, c=greatest_lower_bound(c, d)). 5.85/6.04 fof(prove_p03d, negated_conjecture, least_upper_bound(multiply(a, c), multiply(b, d))!=multiply(b, d)). 5.85/6.04 fof(symmetry_of_glb, axiom, ![X, Y]: greatest_lower_bound(Y, X)=greatest_lower_bound(X, Y)). 5.85/6.04 fof(symmetry_of_lub, axiom, ![X, Y]: least_upper_bound(X, Y)=least_upper_bound(Y, X)). 5.85/6.04 5.85/6.04 Now clausify the problem and encode Horn clauses using encoding 3 of 5.85/6.04 http://www.cse.chalmers.se/~nicsma/papers/horn.pdf. 5.85/6.04 We repeatedly replace C & s=t => u=v by the two clauses: 5.85/6.04 fresh(y, y, x1...xn) = u 5.85/6.04 C => fresh(s, t, x1...xn) = v 5.85/6.04 where fresh is a fresh function symbol and x1..xn are the free 5.85/6.04 variables of u and v. 5.85/6.04 A predicate p(X) is encoded as p(X)=true (this is sound, because the 5.85/6.04 input problem has no model of domain size 1). 5.85/6.04 5.85/6.04 The encoding turns the above axioms into the following unit equations and goals: 5.85/6.04 5.85/6.04 Axiom 1 (symmetry_of_lub): least_upper_bound(X, Y) = least_upper_bound(Y, X). 5.85/6.04 Axiom 2 (glb_absorbtion): greatest_lower_bound(X, least_upper_bound(X, Y)) = X. 5.85/6.04 Axiom 3 (lub_absorbtion): X = least_upper_bound(X, greatest_lower_bound(X, Y)). 5.85/6.04 Axiom 4 (monotony_glb1): multiply(X, greatest_lower_bound(Y, Z)) = greatest_lower_bound(multiply(X, Y), multiply(X, Z)). 5.85/6.04 Axiom 5 (symmetry_of_glb): greatest_lower_bound(X, Y) = greatest_lower_bound(Y, X). 5.85/6.04 Axiom 6 (monotony_glb2): greatest_lower_bound(multiply(X, Y), multiply(Z, Y)) = multiply(greatest_lower_bound(X, Z), Y). 5.85/6.04 Axiom 7 (associativity_of_glb): greatest_lower_bound(X, greatest_lower_bound(Y, Z)) = greatest_lower_bound(greatest_lower_bound(X, Y), Z). 5.85/6.04 Axiom 8 (p03d_1): b = least_upper_bound(a, b). 5.85/6.04 Axiom 9 (p03d_2): c = greatest_lower_bound(c, d). 5.85/6.04 5.85/6.04 Goal 1 (prove_p03d): least_upper_bound(multiply(a, c), multiply(b, d)) = multiply(b, d). 5.85/6.04 Proof: 5.85/6.04 least_upper_bound(multiply(a, c), multiply(b, d)) 5.85/6.04 = { by axiom 1 (symmetry_of_lub) } 5.85/6.04 least_upper_bound(multiply(b, d), multiply(a, c)) 5.85/6.04 = { by axiom 2 (glb_absorbtion) } 5.85/6.04 least_upper_bound(multiply(b, d), multiply(greatest_lower_bound(a, least_upper_bound(a, b)), c)) 5.85/6.04 = { by axiom 8 (p03d_1) } 5.85/6.04 least_upper_bound(multiply(b, d), multiply(greatest_lower_bound(a, b), c)) 5.85/6.04 = { by axiom 6 (monotony_glb2) } 5.85/6.04 least_upper_bound(multiply(b, d), greatest_lower_bound(multiply(a, c), multiply(b, c))) 5.85/6.04 = { by axiom 9 (p03d_2) } 5.85/6.04 least_upper_bound(multiply(b, d), greatest_lower_bound(multiply(a, c), multiply(b, greatest_lower_bound(c, d)))) 5.85/6.04 = { by axiom 4 (monotony_glb1) } 5.85/6.04 least_upper_bound(multiply(b, d), greatest_lower_bound(multiply(a, c), greatest_lower_bound(multiply(b, c), multiply(b, d)))) 5.85/6.04 = { by axiom 7 (associativity_of_glb) } 5.85/6.04 least_upper_bound(multiply(b, d), greatest_lower_bound(greatest_lower_bound(multiply(a, c), multiply(b, c)), multiply(b, d))) 5.85/6.04 = { by axiom 5 (symmetry_of_glb) } 5.85/6.04 least_upper_bound(multiply(b, d), greatest_lower_bound(multiply(b, d), greatest_lower_bound(multiply(a, c), multiply(b, c)))) 5.85/6.04 = { by axiom 6 (monotony_glb2) } 5.85/6.04 least_upper_bound(multiply(b, d), greatest_lower_bound(multiply(b, d), multiply(greatest_lower_bound(a, b), c))) 5.85/6.04 = { by axiom 3 (lub_absorbtion) } 5.85/6.04 multiply(b, d) 5.85/6.04 % SZS output end Proof 5.85/6.04 5.85/6.04 RESULT: Unsatisfiable (the axioms are contradictory). 5.85/6.04 EOF