(*===========================================================
                expe AND bottom
============================================================*)

(* expo and between in an edge: *)

Definition expe(m:fmap)(z t:dart):=
  MA0.expo m z t.Definition betweene(m:fmap)(z v t:dart):=
  MA0.between m z v t.

Lemma Iter_cA0_I: forall(m:fmap)(d z:dart)(t:tag)(p:point)(i:nat), inv_hmap (I m d t p) -> exd m z -> Iter (cA (I m d t p) zero) i z = Iter (cA m zero) i z.