intro.
rewrite al_constant.
unfold al' in |- *.
unfold compo' in |- *.
unfold al3 in |- *.
unfold al_2_1 in |- *.
unfold compo_2_1 in |- *.
rewrite al2_constant.
unfold al1 in |- *.
trivial.
Qed.

Lemma mem_mem' :
forall t : nat,
mem t di_init cx_init al_init mem_init =
mem' t di_init cx_init al_init mem_init DC_a DC_d.