intros Q a p q H'; generalize a; elim H'; clear a H'; auto.
simpl in |- *; auto.
intros a b nZb p0 q0 r H' H'0 H'1 a0 H'2 H'3.
cut (~ zeroP (A:=A) A0 eqA (n:=n) (multTerm (A:=A) multA (n:=n) a0 a));
[ intros nZ0 | idtac ]; auto.
apply reducetop with (b := b) (nZb := nZb) (q := q0); auto.
apply divTerm_def with (nZb := nZb); auto.
apply
(eqTerm_trans _ _ _ _ _ _ _ _ _ cs n)
with
(y := multTerm (A:=A) multA (n:=n)
(multTerm (A:=A) multA (n:=n) a0
(divTerm (A:=A) (A0:=A0) (eqA:=eqA) divA (n:=n) a (b:=b) nZb))
b); [ auto | idtac ].
apply
(eqTerm_trans _ _ _ _ _ _ _ _ _ cs n)
with
(y := multTerm (A:=A) multA (n:=n) a0
(multTerm (A:=A) multA (n:=n)
(divTerm (A:=A) (A0:=A0) (eqA:=eqA) divA (n:=n) a (b:=b) nZb)
b)); [ auto | idtac ].
apply multTerm_assoc with (1 := cs); auto.
apply eqTerm_multTerm_comp with (1 := cs); auto.
apply (eqTerm_sym _ _ _ _ _ _ _ _ _ cs n);
apply divTerm_multTerm_l with (1 := cs); auto.
apply
(eqp_trans _ _ _ _ _ _ _ _ _ cs n)
with
(y := mults (A:=A) multA (n:=n) a0
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM
ltM_dec a b nZb p0 q0)); auto.
apply spminusf_multTerm with (1 := cs); auto.
apply canonical_imp_canonical with (a := a); auto.
apply canonical_imp_canonical with (a := b); auto.
apply inPolySet_imp_canonical with (L := Q); auto.
apply nzeroP_multTerm with (1 := cs); auto.
apply canonical_nzeroP with (ltM := ltM) (p := p0); auto.
intros a b p0 q0 H' H'0 H'1 a0 H'2 H'3.
simpl in |- *; apply reduceskip; auto.
apply H'0; auto.
apply canonical_imp_canonical with (a := a); auto.
Qed.
Hint Resolve reduce_mults.

Theorem reduce_mults_inv_lem :
forall (Q : list (poly A0 eqA ltM)) (p q : list (Term A n)),
reduce Q p q ->
forall r : list (Term A n),
canonical A0 eqA ltM r ->
p = mults (A:=A) multA (n:=n) (invTerm (A:=A) invA (n:=n) (T1 A1 n)) r ->
reduce Q r
(mults (A:=A) multA (n:=n) (invTerm (A:=A) invA (n:=n) (T1 A1 n)) q).