proposition: Lemma cpoly_mult_cr_zero : forall p, cpoly_mult_cr_cs p [0] [=] cpoly_zero_cs.
proof: Proof. intro; pattern p in |- *; apply cpoly_ind_cs. rewrite cpoly_zero_mult_cr. algebra. intros. rewrite cpoly_lin_mult_cr. apply _cpoly_lin_eq_zero. split. algebra. assumption. Qed.
imports: CoRN.algebra.CRing_Homomorphisms CoRN.tactics.Rational