proposition: Lemma equivlistA_app_idem l : equivlistA eqA (l ++ l) l.
proof: Proof. split; apply InA_app_idem. Qed.
imports: Coq.Lists.List Coq.Lists.SetoidList MathClasses.interfaces.abstract_algebra MathClasses.interfaces.monads MathClasses.theory.monads