1 include "logic/equality.ma".
3 (* Inclusion of: ROB005-1.p *)
5 (* -------------------------------------------------------------------------- *)
7 (* File : ROB005-1 : TPTP v3.7.0. Released v1.0.0. *)
9 (* Domain : Robbins Algebra *)
11 (* Problem : Exists an idempotent element => Boolean *)
13 (* Version : [Win90] (equality) axioms. *)
15 (* English : If there is an element c such that c+c=c, then the algebra *)
19 (* Refs : [HMT71] Henkin et al. (1971), Cylindrical Algebras *)
21 (* : [Win90] Winker (1990), Robbins Algebra: Conditions that make a *)
23 (* : [Ove90] Overbeek (1990), ATP competition announced at CADE-10 *)
25 (* : [LW92] Lusk & Wos (1992), Benchmark Problems in Which Equalit *)
27 (* : [Ove93] Overbeek (1993), The CADE-11 Competitions: A Personal *)
29 (* : [LM93] Lusk & McCune (1993), Uniform Strategies: The CADE-11 *)
31 (* : [Zha93] Zhang (1993), Automated Proofs of Equality Problems in *)
33 (* Source : [Ove90] *)
35 (* Names : CADE-11 Competition Eq-2 [Ove90] *)
37 (* : Lemma 2.4 [Win90] *)
41 (* : THEOREM EQ-2 [LM93] *)
43 (* : PROBLEM 2 [Zha93] *)
45 (* : robbins.occ.in [OTTER] *)
47 (* Status : Unsatisfiable *)
49 (* Rating : 0.22 v3.4.0, 0.25 v3.3.0, 0.14 v3.2.0, 0.07 v3.1.0, 0.11 v2.7.0, 0.09 v2.6.0, 0.17 v2.5.0, 0.00 v2.4.0, 0.33 v2.3.0, 0.67 v2.2.1, 0.67 v2.2.0, 0.71 v2.1.0, 0.88 v2.0.0 *)
51 (* Syntax : Number of clauses : 5 ( 0 non-Horn; 5 unit; 2 RR) *)
53 (* Number of atoms : 5 ( 5 equality) *)
55 (* Maximal clause size : 1 ( 1 average) *)
57 (* Number of predicates : 1 ( 0 propositional; 2-2 arity) *)
59 (* Number of functors : 5 ( 3 constant; 0-2 arity) *)
61 (* Number of variables : 7 ( 0 singleton) *)
63 (* Maximal term depth : 6 ( 3 average) *)
65 (* Comments : Commutativity, associativity, and Huntington's axiom *)
67 (* axiomatize Boolean algebra. *)
69 (* -------------------------------------------------------------------------- *)
71 (* ----Include axioms for Robbins algebra *)
73 (* Inclusion of: Axioms/ROB001-0.ax *)
75 (* -------------------------------------------------------------------------- *)
77 (* File : ROB001-0 : TPTP v3.7.0. Released v1.0.0. *)
79 (* Domain : Robbins algebra *)
81 (* Axioms : Robbins algebra axioms *)
83 (* Version : [Win90] (equality) axioms. *)
87 (* Refs : [HMT71] Henkin et al. (1971), Cylindrical Algebras *)
89 (* : [Win90] Winker (1990), Robbins Algebra: Conditions that make a *)
91 (* Source : [OTTER] *)
93 (* Names : Lemma 2.2 [Win90] *)
97 (* Syntax : Number of clauses : 3 ( 0 non-Horn; 3 unit; 0 RR) *)
99 (* Number of atoms : 3 ( 3 equality) *)
101 (* Maximal clause size : 1 ( 1 average) *)
103 (* Number of predicates : 1 ( 0 propositional; 2-2 arity) *)
105 (* Number of functors : 2 ( 0 constant; 1-2 arity) *)
107 (* Number of variables : 7 ( 0 singleton) *)
109 (* Maximal term depth : 6 ( 3 average) *)
113 (* -------------------------------------------------------------------------- *)
115 (* -------------------------------------------------------------------------- *)
117 (* -------------------------------------------------------------------------- *)
118 ntheorem prove_huntingtons_axiom:
119 (∀Univ:Type.∀X:Univ.∀Y:Univ.∀Z:Univ.
121 ∀add:∀_:Univ.∀_:Univ.Univ.
124 ∀negate:∀_:Univ.Univ.
125 ∀H0:eq Univ (add c c) c.
126 ∀H1:∀X:Univ.∀Y:Univ.eq Univ (negate (add (negate (add X Y)) (negate (add X (negate Y))))) X.
127 ∀H2:∀X:Univ.∀Y:Univ.∀Z:Univ.eq Univ (add (add X Y) Z) (add X (add Y Z)).
128 ∀H3:∀X:Univ.∀Y:Univ.eq Univ (add X Y) (add Y X).eq Univ (add (negate (add a (negate b))) (negate (add (negate a) (negate b)))) b)
143 nauto by H0,H1,H2,H3 ##;
144 ntry (nassumption) ##;
147 (* -------------------------------------------------------------------------- *)