Definition Red (L : list (poly A0 eqA ltM)) : list (poly A0 eqA ltM) :=
  redacc L nil.

Theorem cb_redacc : forall (L1 L2 : list (poly A0 eqA ltM)) (p : poly A0 eqA ltM), In p L1 -> Cb A A0 eqA plusA multA eqA_dec n ltM ltM_dec p (redacc L1 L2 ++ L2).