intros aP R Q a b c H' H'0 H'1 H'2; try assumption.
apply lem_redln_cons with (Q := c :: Q) (c := c); auto.
Qed.

Theorem redInclP :
forall (P Q R : list (poly A0 eqA ltM)) (a b : poly A0 eqA ltM),
redIn a b P Q R ->
forall P1 : list (poly A0 eqA ltM), incl P P1 -> redIn a b P1 Q R.