Definition inj_offset_aligned (delta: Z) (size: Z) : Prop :=
forall chunk, size_chunk chunk <= size -> (align_chunk chunk | delta).

Axiom alloc_parallel_inject:
forall f m1 m2 lo1 hi1 m1' b1 lo2 hi2,
inject f m1 m2 ->
alloc m1 lo1 hi1 = (m1', b1) ->
lo2 <= lo1 -> hi1 <= hi2 ->
exists f', exists m2', exists b2,
alloc m2 lo2 hi2 = (m2', b2)
/\ inject f' m1' m2'
/\ inject_incr f f'
/\ f' b1 = Some(b2, 0)
/\ (forall b, b <> b1 -> f' b = f b).