+ intros. xomega.
+ induction 1.
- apply Mem.nextblock_storebytes in H;
rewrite H; xomega.
- apply Mem.nextblock_alloc in H.
rewrite H. clear. xomega.
- apply nextblock_freelist in H.
rewrite H; xomega.
- xomega.
Qed.

Lemma ple_loadbytes m b ofs n bytes
(LD: Mem.loadbytes m b ofs n = Some bytes)
m1 (PLE: perm_lesseq m m1) (N: 0 <= n):
Mem.loadbytes m1 b ofs n = Some bytes.