the boolean equality beqb, that is just the xand function, then prove that
beqb b1 b2 is true if and only if b1=b2, and finally build the type DeqBool by
instantiating the DeqSet record with the previous information *)
the boolean equality beqb, that is just the xand function, then prove that
beqb b1 b2 is true if and only if b1=b2, and finally build the type DeqBool by
instantiating the DeqSet record with the previous information *)