Corollary or_zero_l: forall x, or zero x = x.

(* Specifications: *)
Theorem or_mone: forall x, or x mone = mone.
Theorem or_idem: forall x, or x x = x.
Theorem and_or_distrib: forall x y z, and x (or y z) = or (and x y) (and x z).
Theorem or_mone: forall x, or x mone = mone.
Theorem or_idem: forall x, or x x = x.
Theorem and_or_distrib: forall x y z, and x (or y z) = or (and x y) (and x z).