fact: Definition pickinSet : forall a : Term A n, ~ zeroP (A:=A) A0 eqA (n:=n) a -> forall Q : list (poly A0 eqA ltM), {p : list (Term A n) | pickinSetp A A0 eqA multA divA n ltM a p Q} + {(forall (b : Term A n) (p q : list (Term A n)), inPolySet A A0 eqA n ltM p Q -> divP A A0 eqA multA divA n a b -> p <> pX b q)}.