Definition mem_wd' m m' := forall b ofs, 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'))).

Lemma mem_wd'_store: forall m0 m b ofs v m' chunk (WDm: mem_wd' m0 m) (ST: Mem.store chunk m b ofs v = Some m') (V: val_valid v m0), mem_wd' m0 m'.