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 In_inv_2 : forall k k' e e' l, InA eqk (k, e) ((k', e') :: l) -> ~ eq k k' -> InA eqk (k, e) l.