(*memories that do not contain "dangling pointers"*)
Definition mem_wd m := Mem.inject_neutral (Mem.nextblock m) m.

Lemma mem_wdI: forall m, (forall (b:block) ofs (R:Mem.perm m b ofs Cur Readable), memval_inject (Mem.flat_inj (Mem.nextblock m)) (ZMap.get ofs (PMap.get b (Mem.mem_contents m))) (ZMap.get ofs (PMap.get b (Mem.mem_contents m)))) -> mem_wd m.