fact: Definition POneSubst (P1: Pol) (cM1: C * Mon) (P2: Pol): option Pol := let (c,M1) := cM1 in let (Q1,R1) := MFactor P1 c M1 in match R1 with (Pc c) => if c ?=! cO then None else Some (Padd Q1 (Pmul P2 R1)) | _ => Some (Padd Q1 (Pmul P2 R1)) end.
imports: Setoid Morphisms BinList BinPos BinNat BinInt Ring_theory