Program Definition juicy_mem_storebytes j b ofs bytes: option juicy_mem :=
  if range_perm_dec (m_dry j) b ofs (ofs + Z_of_nat (length bytes)) Cur Writable
    then Some (storebytes_juicy_mem j _ b ofs bytes _)
    else None.

Lemma juicy_mem_storebytes_succeeds: forall j j' b ofs bytes, juicy_mem_storebytes j b ofs bytes = Some j' -> exists m', storebytes (m_dry j) b ofs bytes = Some m' /\ m' = m_dry j'.