--- /dev/null
+
+include "logic/equality.ma".
+(* Inclusion of: LAT008-1.p *)
+(* -------------------------------------------------------------------------- *)
+(* File : LAT008-1 : TPTP v3.1.1. Released v2.2.0. *)
+(* Domain : Lattice Theory (Distributive lattices) *)
+(* Problem : Sholander's basis for distributive lattices, part 5 (of 6). *)
+(* Version : [MP96] (equality) axioms. *)
+(* English : This is part of the proof that Sholanders 2-basis for *)
+(* distributive lattices is correct. Here we prove the absorption *)
+(* law x v (x ^ y) = x. *)
+(* Refs : [McC98] McCune (1998), Email to G. Sutcliffe *)
+(* : [MP96] McCune & Padmanabhan (1996), Automated Deduction in Eq *)
+(* Source : [McC98] *)
+(* Names : LT-3-f [MP96] *)
+(* Status : Unsatisfiable *)
+(* Rating : 0.07 v3.1.0, 0.11 v2.7.0, 0.00 v2.2.1 *)
+(* Syntax : Number of clauses : 3 ( 0 non-Horn; 3 unit; 1 RR) *)
+(* Number of atoms : 3 ( 3 equality) *)
+(* Maximal clause size : 1 ( 1 average) *)
+(* Number of predicates : 1 ( 0 propositional; 2-2 arity) *)
+(* Number of functors : 4 ( 2 constant; 0-2 arity) *)
+(* Number of variables : 5 ( 1 singleton) *)
+(* Maximal term depth : 3 ( 2 average) *)
+(* Comments : *)
+(* -------------------------------------------------------------------------- *)
+(* ----Sholander's 2-basis for distributive lattices: *)
+(* ----Denial of the conclusion: *)
+theorem prove_absorbtion_dual:
+ \forall Univ:Set.
+\forall a:Univ.
+\forall b:Univ.
+\forall join:\forall _:Univ.\forall _:Univ.Univ.
+\forall meet:\forall _:Univ.\forall _:Univ.Univ.
+\forall H0:\forall X:Univ.\forall Y:Univ.\forall Z:Univ.eq Univ (meet X (join Y Z)) (join (meet Z X) (meet Y X)).
+\forall H1:\forall X:Univ.\forall Y:Univ.eq Univ (meet X (join X Y)) X.eq Univ (join a (meet a b)) a
+.
+intros.
+autobatch paramodulation timeout=100;
+try assumption.
+print proofterm.
+qed.
+(* -------------------------------------------------------------------------- *)