Definition bmatch (m: mem) (b: block) (ab: ablock) : Prop :=
  smatch m b ab.(ab_summary) /\
  forall chunk ofs v, Mem.load chunk m b ofs = Some v -> vmatch v (ablock_load chunk ab ofs).

Lemma ablock_store_sound: forall chunk m b ofs v m' ab av, Mem.store chunk m b ofs v = Some m' -> bmatch m b ab -> vmatch v av -> bmatch m' b (ablock_store chunk ab ofs av).