Notation orb_prop2 := orb_prop_elim (only parsing).

(* Specifications: *)
Lemma orb_prop_intro :
forall a b:bool, Is_true a \/ Is_true b -> Is_true (a || b).
Lemma andb_prop_intro :
forall b1 b2:bool, Is_true b1 /\ Is_true b2 -> Is_true (b1 && b2).