Removed nat_case, nat_rec, and natE (now provided by datatype
package).
(* Title: HOL/AxClasses/Tutorial/Xor.thy
ID: $Id$
Author: Markus Wenzel, TU Muenchen
Define overloaded constants "<*>", "inverse", "1" on type "bool".
*)
Xor = Group +
defs
prod_bool_def "x <*> y == x ~= (y::bool)"
inverse_bool_def "inverse x == x::bool"
unit_bool_def "1 == False"
end