proposition: Lemma incl_rev_intro : forall l l' : list A, rev l [= rev l' -> l [= l'.
proof: Proof. intros. trans (rev l). apply incl_rev. trans (rev l'). hyp. apply rev_incl. Qed.
imports: CoLoR(LogicUtil EqUtil RelUtil BoolUtil NatUtil) Coq(Setoid SetoidList FunInd)