(** The sizes of blocks appearing in [e] are respected. *)
Definition match_bounds (e: Csharpminor.env) (m: mem) : Prop :=
forall id b sz ofs p,
PTree.get id e = Some(b, sz) -> Mem.perm m b ofs Max p -> 0 <= ofs < sz.

Lemma match_bounds_invariant:
forall e m1 m2,
match_bounds e m1 ->
(forall id b sz ofs p,
PTree.get id e = Some(b, sz) -> Mem.perm m2 b ofs Max p -> Mem.perm m1 b ofs Max p) ->
match_bounds e m2.