Definition redacc : list poly -> list poly -> list poly.Definition red (L : list poly) : list poly := redacc L nil.

Theorem redacc_divp : forall (L1 L2 : list poly) (p : poly), ~ zerop p -> In p (L1 ++ L2) -> exists q : poly, In q (redacc L1 L2 ++ L2) /\ divp p q /\ ~ zerop q.