fact: Definition PNSubst (P1: Pol) (cM1: C * Mon) (P2: Pol) (n: nat): option Pol := match POneSubst P1 cM1 P2 with Some P3 => match n with S n1 => Some (PNSubst1 P3 cM1 P2 n1) | _ => None end | _ => None end.
imports: Setoid Morphisms BinList BinPos BinNat BinInt Ring_theory