--- /dev/null
+include "logic/equality.ma".
+
+(* Inclusion of: BOO012-2.p *)
+
+(* -------------------------------------------------------------------------- *)
+
+(* File : BOO012-2 : TPTP v3.7.0. Released v1.0.0. *)
+
+(* Domain : Boolean Algebra *)
+
+(* Problem : Inverse is an involution *)
+
+(* Version : [ANL] (equality) axioms. *)
+
+(* English : *)
+
+(* Refs : *)
+
+(* Source : [ANL] *)
+
+(* Names : prob8.ver2.in [ANL] *)
+
+(* Status : Unsatisfiable *)
+
+(* Rating : 0.00 v2.2.1, 0.11 v2.2.0, 0.14 v2.1.0, 0.25 v2.0.0 *)
+
+(* Syntax : Number of clauses : 15 ( 0 non-Horn; 15 unit; 1 RR) *)
+
+(* Number of atoms : 15 ( 15 equality) *)
+
+(* Maximal clause size : 1 ( 1 average) *)
+
+(* Number of predicates : 1 ( 0 propositional; 2-2 arity) *)
+
+(* Number of functors : 6 ( 3 constant; 0-2 arity) *)
+
+(* Number of variables : 24 ( 0 singleton) *)
+
+(* Maximal term depth : 3 ( 2 average) *)
+
+(* Comments : *)
+
+(* -------------------------------------------------------------------------- *)
+
+(* ----Include boolean algebra axioms for equality formulation *)
+
+(* Inclusion of: Axioms/BOO003-0.ax *)
+
+(* -------------------------------------------------------------------------- *)
+
+(* File : BOO003-0 : TPTP v3.7.0. Released v1.0.0. *)
+
+(* Domain : Boolean Algebra *)
+
+(* Axioms : Boolean algebra (equality) axioms *)
+
+(* Version : [ANL] (equality) axioms. *)
+
+(* English : *)
+
+(* Refs : *)
+
+(* Source : [ANL] *)
+
+(* Names : *)
+
+(* Status : *)
+
+(* Syntax : Number of clauses : 14 ( 0 non-Horn; 14 unit; 0 RR) *)
+
+(* Number of atoms : 14 ( 14 equality) *)
+
+(* Maximal clause size : 1 ( 1 average) *)
+
+(* Number of predicates : 1 ( 0 propositional; 2-2 arity) *)
+
+(* Number of functors : 5 ( 2 constant; 0-2 arity) *)
+
+(* Number of variables : 24 ( 0 singleton) *)
+
+(* Maximal term depth : 3 ( 2 average) *)
+
+(* Comments : *)
+
+(* -------------------------------------------------------------------------- *)
+
+(* -------------------------------------------------------------------------- *)
+
+(* -------------------------------------------------------------------------- *)
+ntheorem prove_inverse_is_an_involution:
+ (∀Univ:Type.∀X:Univ.∀Y:Univ.∀Z:Univ.
+∀add:∀_:Univ.∀_:Univ.Univ.
+∀additive_identity:Univ.
+∀inverse:∀_:Univ.Univ.
+∀multiplicative_identity:Univ.
+∀multiply:∀_:Univ.∀_:Univ.Univ.
+∀x:Univ.
+∀H0:∀X:Univ.eq Univ (add additive_identity X) X.
+∀H1:∀X:Univ.eq Univ (add X additive_identity) X.
+∀H2:∀X:Univ.eq Univ (multiply multiplicative_identity X) X.
+∀H3:∀X:Univ.eq Univ (multiply X multiplicative_identity) X.
+∀H4:∀X:Univ.eq Univ (multiply (inverse X) X) additive_identity.
+∀H5:∀X:Univ.eq Univ (multiply X (inverse X)) additive_identity.
+∀H6:∀X:Univ.eq Univ (add (inverse X) X) multiplicative_identity.
+∀H7:∀X:Univ.eq Univ (add X (inverse X)) multiplicative_identity.
+∀H8:∀X:Univ.∀Y:Univ.∀Z:Univ.eq Univ (multiply X (add Y Z)) (add (multiply X Y) (multiply X Z)).
+∀H9:∀X:Univ.∀Y:Univ.∀Z:Univ.eq Univ (multiply (add X Y) Z) (add (multiply X Z) (multiply Y Z)).
+∀H10:∀X:Univ.∀Y:Univ.∀Z:Univ.eq Univ (add X (multiply Y Z)) (multiply (add X Y) (add X Z)).
+∀H11:∀X:Univ.∀Y:Univ.∀Z:Univ.eq Univ (add (multiply X Y) Z) (multiply (add X Z) (add Y Z)).
+∀H12:∀X:Univ.∀Y:Univ.eq Univ (multiply X Y) (multiply Y X).
+∀H13:∀X:Univ.∀Y:Univ.eq Univ (add X Y) (add Y X).eq Univ (inverse (inverse x)) x)
+.
+#Univ ##.
+#X ##.
+#Y ##.
+#Z ##.
+#add ##.
+#additive_identity ##.
+#inverse ##.
+#multiplicative_identity ##.
+#multiply ##.
+#x ##.
+#H0 ##.
+#H1 ##.
+#H2 ##.
+#H3 ##.
+#H4 ##.
+#H5 ##.
+#H6 ##.
+#H7 ##.
+#H8 ##.
+#H9 ##.
+#H10 ##.
+#H11 ##.
+#H12 ##.
+#H13 ##.
+nauto by H0,H1,H2,H3,H4,H5,H6,H7,H8,H9,H10,H11,H12,H13 ##;
+ntry (nassumption) ##;
+nqed.
+
+(* -------------------------------------------------------------------------- *)