intros a; case a; simpl in |- *.
intros x c b Q H'.
cut (canonical A0 eqA ltM b);
[ intros Op1 | apply canonical_reduce with (1 := cs) (3 := H') ];
auto.
case reduce_inv2 with (1 := cs) (3 := H'); auto;
(intros c1 E; elim E; intros d E0; elim E0; intros H'7 H'8; elim H'8;
intros H'9 H'10; elim H'10; intros H'11 H'12; clear H'10 H'8 E0 E).
apply
CombLinear_comp
with
(p := minuspf A A0 A1 eqA invA minusA multA eqA_dec n ltM ltM_dec x
(mults (A:=A) multA (n:=n) d c1)); auto.
apply CombLinear_minuspf; auto.
apply CombLinear_id; auto.
generalize c H'; case x; auto.
intros c2 H'0; inversion H'0; auto.
intros t l c0 H'0;
change
(inPolySet A A0 eqA n ltM (pX t l)
(exist (canonical A0 eqA ltM) (pX t l) c0 :: Q))
in |- *; auto.
apply incons with (a := t) (p := l) (P := Q); auto.
apply CombLinear_mults1; auto.
apply CombLinear_id; auto.
apply inskip; auto.
apply (eqp_sym _ _ _ _ _ _ _ _ _ cs n); auto.
Qed.

Theorem CombLinear_compo :
forall (p : list (Term A n)) (L1 : list (poly A0 eqA ltM)),
CombLinear L1 p ->
forall L2 : list (poly A0 eqA ltM),
(forall q : list (Term A n),
inPolySet A A0 eqA n ltM q L1 -> CombLinear L2 q) ->
CombLinear L2 p.