intros a b c nZc p q H' H'0 H'1 H'2; unfold spminusf in |- *.
apply
(eqp_trans _ _ _ _ _ _ _ _ _ cs n)
with
(y := minuspf A A0 A1 eqA invA minusA multA eqA_dec n ltM ltM_dec
(mults (A:=A) multA (n:=n) a p)
(mults (A:=A) multA (n:=n)
(multTerm (A:=A) multA (n:=n) a
(divTerm (A:=A) (A0:=A0) (eqA:=eqA) divA (n:=n) b (b:=c)
nZc)) q)); [ auto | idtac ].
apply minuspf_comp with (1 := cs); auto.
apply canonical_mults with (1 := cs); auto.
apply
nzeroP_comp_eqTerm
with
(1 := cs)
(a := multTerm (A:=A) multA (n:=n) a
(divTerm (A:=A) (A0:=A0) (eqA:=eqA) divA (n:=n) b (b:=c) nZc));
auto.
apply (eqTerm_sym _ _ _ _ _ _ _ _ _ cs n);
apply divTerm_multTerm_l with (1 := cs).
inversion H'1; auto.
apply
(eqp_trans _ _ _ _ _ _ _ _ _ cs n)
with
(y := minuspf A A0 A1 eqA invA minusA multA eqA_dec n ltM ltM_dec
(mults (A:=A) multA (n:=n) a p)
(mults (A:=A) multA (n:=n) a
(mults (A:=A) multA (n:=n)
(divTerm (A:=A) (A0:=A0) (eqA:=eqA) divA (n:=n) b (b:=c)
nZc) q))); [ auto | idtac ].
apply (eqp_sym _ _ _ _ _ _ _ _ _ cs n);
apply mults_dist_minuspf with (1 := cs); auto.
Qed.
Hint Resolve spminusf_plusTerm spminusf_multTerm.

Theorem spminusf_minusTerm_l :
forall (a b : Term A n) (nZb : ~ zeroP (A:=A) A0 eqA (n:=n) b)
(p q r : list (Term A n)),
canonical A0 eqA ltM p ->
canonical A0 eqA ltM q ->
canonical A0 eqA ltM r ->
divP A A0 eqA multA divA n a b ->
eqP A eqA n
(spminusf a b nZb
(minuspf A A0 A1 eqA invA minusA multA eqA_dec n ltM ltM_dec p q) r)
(minuspf A A0 A1 eqA invA minusA multA eqA_dec n ltM ltM_dec
(spminusf a b nZb p r) q).