(** Results about id injections*)
Definition id_ren m :=
fun b => if is_left (valid_block_dec m b) then Some b else None.
Hint Unfold id_ren.

Lemma id_ren_restr:
forall pmap m (Hlt: permMapLt pmap (getMaxPerm m)),
id_ren m = id_ren (restrPermMap Hlt).