(** ** Properties of [storebytes]. *)
(** [storebytes] preserves block validity, permissions, access validity, and bounds. Moreover, a [storebytes] succeeds if and only if we have write permissions on the addressed memory area. *)

Axiom nextblock_storebytes:
forall m1 b ofs bytes m2, storebytes m1 b ofs bytes = Some m2 ->
nextblock m2 = nextblock m1.