intros.
simpl.
rewrite (space_denote_permute _ _ H).
trivial.
Qed.

Lemma Lseg_unfold_neq:
forall e nextv pi sigma0 e0 e1 sigma s,
fresh freshmax_expr e nextv ->
fresh freshmax_assertion (Assertion pi (sigma0 ++ Lseg e0 e1 :: sigma)) nextv ->
(e === e0) s ->
list_denote pn_atom_denote (@andp _)
(space_denote (sigma0 ++ Lseg e0 e1 :: sigma)) pi s ->
~ (e0 === e1) s ->
existsv nextv
(assertion_denote (Assertion pi (Next e (Var nextv) :: Lseg (Var nextv) e1 :: sigma0 ++ sigma))) s.