Definition minusTerm : Term -> Term -> Term.

(* Specifications: *)
Theorem eqTerm_minusTerm_plusTerm_invTerm : forall a b : Term, eqTerm (minusTerm a b) (plusTerm a (invTerm b)).
Theorem minusTerm_eqT : forall m1 m2 : Term, eqT m1 m2 -> eqT (minusTerm m1 m2) m1.
Theorem zeroP_minusTerm : forall a : Term, zeroP (minusTerm a a).
Theorem multTerm_zeroP_div : forall a b : Term, zeroP (multTerm a b) -> zeroP a \/ zeroP b.
Theorem multTerm_minusTerm_dist_l : forall a b c : Term, eqT a b -> eqTerm (minusTerm (multTerm a c) (multTerm b c)) (multTerm (minusTerm a b) c).
Theorem nzeroP_multTerm : forall a b : Term, ~ zeroP a -> ~ zeroP b -> ~ zeroP (multTerm a b).