(** Properties of [lxor] and others, directly deduced from properties of [xorb] and others. *)
#[global]
Instance land_wd : Proper (eq ==> eq ==> eq) land.
#[global]
Instance lor_wd : Proper (eq ==> eq ==> eq) lor.
#[global]
Instance ldiff_wd : Proper (eq ==> eq ==> eq) ldiff.

Lemma lor_assoc :
forall a b c, lor a (lor b c) == lor (lor a b) c.