(* COROLLARY, OK: *)

Lemma diff_cF_L1_y_1_y_1:forall(m:fmap)(x y:dart)(i j:nat),
inv_hmap m -> prec_L m one x y ->
let y0 := cA m zero y in
let y_1:= cA_1 m one y in
let x1:= cA m one x in
let x10:= cA m zero x1 in
let dx := MF.degree m x in
let m1:= L m one x y in
y0 = Iter (cF m) j x -> expf m x y0 ->
j + 1 + i <= dx - 1 -> 0 < i ->
Iter (cF m1) i y_1 <> y_1.