intros a; case a; simpl in |- *; auto.
intros x H' P Q H'0 H'1.
apply CombLinear_incl with (1 := cs) (P := P); auto.
intros a0 H'2.
apply Incl_inp_inPolySet with (P := P); auto.
Qed.

Theorem Cb_in1 :
forall (a b : poly A0 eqA ltM) (Q : list (poly A0 eqA ltM)),
Cb a Q -> Cb a (b :: Q).