intros Q p q r s H' H'0 H'1 H'2; inversion H'.
apply reducestar0; auto.
apply reduceplus_eqp_com with (p := p) (q := q) (1 := cs); auto.
apply irreducible_eqp_com with (p := q) (1 := cs); auto.
apply canonical_reduceplus with (1 := cs) (3 := H); auto.
Qed.
Definition mks :
forall p : list (Term A n), canonical A0 eqA ltM p -> poly A0 eqA ltM.
intros p H'; exists p; exact H'.
Defined.
Definition selectdivf :
forall a : Term A n,
~ zeroP (A:=A) A0 eqA (n:=n) a ->
forall Q : list (poly A0 eqA ltM),
{q : list (Term A n) |
exists b : Term A n,
(exists p : list (Term A n),
divP A A0 eqA multA divA n a b /\
inPolySet A A0 eqA n ltM q Q /\ q = pX b p)} +
{(forall (b : Term A n) (q : list (Term A n)),
inPolySet A A0 eqA n ltM (pX b q) Q -> ~ divP A A0 eqA multA divA n a b)}.
intros a Z Q; elim Q; auto.
right.
intros b q H'; inversion_clear H'.
intros a0; case a0.
intros x; case x.
intros c l H'; case H'.
intros H'1; case H'1.
intros x0 H'0; left.
exists x0.
elim H'0; intros b E; elim E; intros p E0; elim E0; intros H'2 H'3; elim H'3;
intros H'4 H'5; try exact H'5; clear H'3 E0 E H'0.
exists b; exists p; split; [ idtac | split ]; auto.
apply inskip; auto.
intros H'0; right.
intros b q H'1; inversion_clear H'1; auto.
apply H'0 with (q := q); auto.
intros a1 l c l0 H'; case (divP_dec _ _ _ _ _ _ _ _ _ cs n a a1); auto.
apply canonical_nzeroP with (p := l) (ltM := ltM); auto.
intros divP1; left; exists (pX a1 l); auto.
exists a1; exists l; split; [ idtac | split ]; auto.
change
(inPolySet A A0 eqA n ltM (pX a1 l)
(exist (canonical A0 eqA ltM) (pX a1 l) c :: l0))
in |- *.
apply incons with (a := a1) (p := l) (H := c); auto.
intros divP1; case H'; intros Hyp1.
case Hyp1.
intros x0 H'0; left; exists x0.
elim H'0; intros b E; elim E; intros p E0; elim E0; intros H'1 H'2; elim H'2;
intros H'3 H'4; try exact H'4; clear H'2 E0 E H'0.
exists b; exists p; split; [ idtac | split ]; auto.
apply inskip; auto.
right.
intros b q H'1; generalize divP1; inversion_clear H'1; eauto.
Qed.
Definition selectpolyf :
forall (Q : list (poly A0 eqA ltM)) (r : list (Term A n)),
canonical A0 eqA ltM r ->
{q : list (Term A n) |
reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q r q} +
{irreducible A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q r}.
intros Q r; elim r.
intros H'; right;
change
(irreducible A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pO A n)) in |- *; apply pO_irreducible; auto.
intros a l H' H'0.
cut (canonical A0 eqA ltM l);
[ intros C0 | apply canonical_imp_canonical with (a := a); auto ].
cut (~ zeroP (A:=A) A0 eqA (n:=n) a);
[ intros Z0 | apply canonical_nzeroP with (p := l) (ltM := ltM); auto ].
case (selectdivf a Z0 Q); intros Hyp1.
case Hyp1.
intros x0; case x0; left.
absurd True; auto.
elim e; intros b E; elim E; intros p E0; elim E0; intros H'1 H'2; elim H'2;
intros H'3 H'4; inversion H'4; clear H'2 E0 E e.
cut (~ zeroP (A:=A) A0 eqA (n:=n) t); [ intros nZt | idtac ].
exists
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a t nZt l
l0).
elim e; intros b E; elim E; intros p E0; elim E0; intros H'1 H'2; elim H'2;
intros H'3 H'4; clear H'2 E0 E e.
change
(reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l)
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a t
nZt l l0)) in |- *.
apply reducetop_sp with (1 := cs); auto.
rewrite (pX_invl A n t b l0 p); auto.
apply canonical_nzeroP with (ltM := ltM) (p := l0).
apply inPolySet_imp_canonical with (L := Q); auto.
elim e; intros b E; elim E; intros p E0; elim E0; intros H'1 H'2; elim H'2;
intros H'3 H'4; try exact H'3; clear H'2 E0 E e.
lapply H'; [ intros H'1; case H'1; clear H' | clear H' ].
intros H'; case H'.
intros x H'2; left; exists (pX a x).
change
(reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l) (pX a x)) in |- *.
apply reduceskip; auto.
intros H'; right;
change
(forall q : list (Term A n),
~
reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l) q) in |- *.
intros q; red in |- *; intros H'2; generalize H' Hyp1; inversion_clear H'2.
intros H'3 H'4; lapply (H'4 b q0); [ intros H'7; apply H'7 | idtac ]; auto.
intros H'3 H'4;
absurd
(reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q l q0);
auto.
auto.
Qed.
Definition Reducef :
forall (Q : list (poly A0 eqA ltM)) (p : poly A0 eqA ltM),
{q : poly A0 eqA ltM |
reducestar Q (s2p A A0 eqA n ltM p) (s2p A A0 eqA n ltM q)}.
intros Q p; pattern p in |- *.
apply well_founded_induction with (1 := sltp_wf _ A0 eqA _ ltM os).
intros x; case x.
intros x0; case x0.
intros o H'; simpl in |- *.
exists (mks (pO A n) (canonicalpO A A0 eqA n ltM)); simpl in |- *; auto.
apply reducestar0; auto.
apply Rstar_0; auto.
apply pO_irreducible; auto.
simpl in |- *; intros a l o H'; auto.
cut (~ zeroP (A:=A) A0 eqA (n:=n) a);
[ intros Z0 | apply canonical_nzeroP with (ltM := ltM) (p := l) ];
auto.
lapply (selectdivf a);
[ intros H'1; case (H'1 Q) | idtac ];
auto; intros Div1.
case Div1.
intros x1; case x1.
intros H'0; absurd True; auto.
elim H'0; intros b E; elim E; intros p0 E0; elim E0; intros H'3 H'4; elim H'4;
intros H'5 H'6; inversion_clear H'6; clear H'4 E0 E H'0.
intros a0 l0 H'0.
cut (~ zeroP (A:=A) A0 eqA (n:=n) a0); [ intros nZt | idtac ].
2: apply canonical_nzeroP with (p := l0) (ltM := ltM).
2: apply inPolySet_imp_canonical with (L := Q); auto.
2: elim H'0; intros b E; elim E; intros p0 E0; elim E0; intros H'3 H'4;
elim H'4; intros H'5 H'6; try exact H'5; clear H'4 E0 E H'0.
cut
(canonical A0 eqA ltM
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a a0
nZt l l0)); [ intros Op2 | idtac ]; auto.
lapply
(H'
(mks
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a
a0 nZt l l0) Op2)); [ intros H'4; case H'4 | idtac ];
auto.
intros x2 H'3; exists x2.
apply reducestar0; auto.
apply
Rstar_n
with
(y := spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a
a0 nZt l l0); auto.
elim H'0; intros b E; elim E; intros p0 E0; elim E0; intros H'5 H'6; elim H'6;
intros H'7 H'8; clear H'6 E0 E H'0.
change
(reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l)
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a a0
nZt l l0)) in |- *.
apply reducetop_sp with (1 := cs); auto.
rewrite (pX_invl A n a0 b l0 p0); auto.
inversion_clear H'3; auto.
inversion_clear H'3; auto.
simpl in |- *;
apply
ltP_reduce
with (Q := Q) (eqA_dec := eqA_dec) (ltM_dec := ltM_dec) (1 := cs);
auto.
elim H'0; intros b E; elim E; intros p0 E0; elim E0; intros H'3 H'4; elim H'4;
intros H'5 H'6; clear H'4 E0 E H'0.
change
(reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l)
(spminusf A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec a a0
nZt l l0)) in |- *.
apply reducetop_sp with (1 := cs); auto.
rewrite (pX_invl A n a0 b l0 p0); auto.
apply canonical_spminusf with (1 := cs); auto.
apply canonical_imp_canonical with (a := a); auto.
elim H'0; intros b E; elim E; intros p0 E0; elim E0; intros H'3 H'4; elim H'4;
intros H'5 H'6; clear H'4 E0 E H'0.
apply canonical_imp_canonical with (a := a0); auto.
apply inPolySet_imp_canonical with (L := Q); auto.
elim H'0; intros b E; elim E; intros p0 E0; elim E0; intros H'3 H'4; elim H'4;
intros H'5 H'6; clear H'4 E0 E H'0.
rewrite (pX_invl A n a0 b l0 p0); auto.
cut (canonical A0 eqA ltM l);
[ intros Op2 | apply canonical_imp_canonical with (a := a); auto ].
lapply (H' (mks l Op2)); simpl in |- *; [ intros H'3; case H'3 | idtac ];
auto.
2: change (ltP (A:=A) (n:=n) ltM l (pX a l)) in |- *;
apply ltP_refl_pX with (1 := cs); auto.
intros x1; case x1.
intros x2 c H'4; simpl in |- *; cut (canonical A0 eqA ltM (pX a x2));
[ intros Op3 | auto ].
exists (mks (pX a x2) Op3); simpl in |- *.
apply reducestar0; auto.
change
(reduceplus A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l) (pX a x2)) in |- *.
apply reduceplus_skip with (1 := cs); auto.
inversion_clear H'4; auto.
change
(forall p : list (Term A n),
~
reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a x2) p) in |- *.
intros p0; red in |- *; intros H'5; generalize H'4 Div1; inversion_clear H'5;
simpl in |- *.
intros H'6 H'7; lapply (H'7 b q); [ intros H'10; apply H'10 | idtac ]; auto.
intros H'6 H'7;
absurd
(reduce A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q x2 q);
auto.
inversion_clear H'6; auto.
cut
(reduceplus A A0 A1 eqA invA minusA multA divA eqA_dec n ltM ltM_dec Q
(pX a l) (pX a x2)); [ intros Re0 | idtac ].
apply canonical_reduceplus with (1 := cs) (3 := Re0); auto.
apply reduceplus_skip with (1 := cs); auto.
inversion_clear H'4; auto.
Defined.

Theorem reduce0_reducestar :
forall (Q : list (poly A0 eqA ltM)) (p : list (Term A n)),
canonical A0 eqA ltM p -> exists t : list (Term A n), reducestar Q p t.