Definition smvalid_src (mu : SM_Injection) m1 :=
  forall b1, DOM mu b1 -> Memory.Mem.valid_block m1 b1.

Lemma extern_incr_as_inj: forall mu mu' (INC: extern_incr mu mu') (WD': SM_wd mu'), inject_incr (as_inj mu) (as_inj mu').