Definition spminusf (a b : Term A n) (nZb : ~ zeroP (A:=A) A0 eqA (n:=n) b)
  (p q : list (Term A n)) :=
  minuspf A A0 A1 eqA invA minusA multA eqA_dec n ltM ltM_dec p
    (mults (A:=A) multA (n:=n)
       (divTerm (A:=A) (A0:=A0) (eqA:=eqA) divA (n:=n) a (b:=b) nZb) q).

Theorem divP_minusTerm_comp : forall a b c : Term A n, divP A A0 eqA multA divA n a c -> divP A A0 eqA multA divA n b c -> eqT a b -> ~ zeroP (A:=A) A0 eqA (n:=n) (minusTerm (A:=A) minusA (n:=n) a b) -> divP A A0 eqA multA divA n (minusTerm (A:=A) minusA (n:=n) a b) c.