src/HOL/AxClasses/Tutorial/Xor.ML

removed \BG, \EN;

(*  Title:      HOL/AxClasses/Tutorial/Xor.ML
    ID:         $Id$
    Author:     Markus Wenzel, TU Muenchen

Proof the instantiation theorem bool :: agroup by hand.
*)

open AxClass;

goal_arity Xor.thy ("bool", [], "agroup");
by (axclass_tac []);
by (rewrite_goals_tac
      [Xor.prod_bool_def,Xor.inverse_bool_def, Xor.unit_bool_def]);
by (ALLGOALS (Fast_tac));
qed "bool_in_agroup";