(* OK!! *)

Lemma expf_L1_I_CN:forall (m:fmap)(x y z t:dart),
inv_hmap (L m one x y) -> exd m z ->
let x1 := cA m one x in
let x10 := cA m zero x1 in
let y0 := cA m zero y in
let y_1 := cA_1 m one y in
~ expf m x y0 -> expf (L m one x y) z t ->
( expf m z t
\/ expf m z x /\ expf m t y0
\/ expf m t x /\ expf m z y0 ).