Definition MapsTo (k:key)(e:elt):= InA eqke (k,e).Definition In k m := exists e:elt, MapsTo k e m.Notation Sort := (sort ltk).Notation Inf := (lelistA ltk).

Lemma Sort_In_cons_2 : forall l e e', Sort (e::l) -> InA eqk e' (e::l) -> ltk e e' \/ eqk e e'.