Definition divPp : Term A n -> list (Term A n) -> Prop.Definition divpf :
  forall (a : Term A n) (nZa : ~ zeroP (A:=A) A0 eqA (n:=n) a),
  list (Term A n) -> list (Term A n).

Theorem Rminus_in : forall (r p q : list (Term A n)) (a b : Term A n) (nZb : ~ zeroP (A:=A) A0 eqA (n:=n) b), divPp b r -> In a p -> canonical A0 eqA ltM p -> canonical A0 eqA ltM (pX b q) -> canonical A0 eqA ltM (pX a r) -> In a (Rminus b nZb p (pX b q) r).