intros Q R H'; elim H'; auto.
Qed.
Hint Resolve (Cb_in _ _ _ _ _ _ _ _ _ cs eqA_dec _ _ ltM_dec os).

Theorem Cb_stable :
forall (a : poly A0 eqA ltM) (Q : list (poly A0 eqA ltM)),
Cb A A0 eqA plusA multA eqA_dec n ltM ltM_dec a Q ->
stable Q (addEnd A A0 eqA n ltM a Q).