(* FROM WHERE: *)

(* Specifications: *)
Lemma expf_L0_5:forall (m:fmap)(x y z t:dart),
inv_hmap (L m zero x y) -> exd m z ->
let x_1 := cA_1 m one x in
~ expf m x_1 y ->
(expf m x_1 z /\ expf m y t
\/ expf m x_1 t /\ expf m y z)
-> expf (L m zero x y) z t.