fact: Fixpoint PNSubst1 (P1: Pol) (M1: Mon) (P2: Pol) (n: nat) : Pol := match POneSubst P1 M1 P2 with Some P3 => match n with S n1 => PNSubst1 P3 M1 P2 n1 | _ => P3 end | _ => P1 end.
imports: Setoid Morphisms Env BinPos BinNat BinInt Ring_theory