intros Q; elim Q; simpl in |- *; auto.
intros p H'; elim H'.
intros a l H' p H'0; elim H'0;
[ intros H'1; rewrite H'1; clear H'0 | intros H'1; clear H'0 ];
auto.
case p; simpl in |- *; auto.
intros x; case x; simpl in |- *; auto.
intros c H'0; elim H'0; auto.
intros t l0 c H;
change (inPolySet (pX t l0) (exist (canonical A0 eqA ltM) (pX t l0) c :: l))
in |- *; apply incons.
Qed.

Theorem in_inPolySet :
forall (P : list (poly A0 eqA ltM)) (p : poly A0 eqA ltM),
In p P -> ~ eqP A eqA n (s2p p) (pO A n) -> inPolySet (s2p p) P.