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Definition_ := Finite.on {poly %/ h}. Hypothesis hI : monic_irreducible_poly h. HB.instance Definition _ := Finite.on {poly %/ h with hI}.
HB.instance
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
Definition
card_qfpoly: #|{poly %/ h with hI}| = #|R| ^ (size h).-1. Proof. by rewrite card_monic_qpoly ?hI. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
card_qfpoly
card_qfpoly_gt1: 1 < #|{poly %/ h with hI}|. Proof. by have := card_finNzRing_gt1 {poly %/ h with hI}. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
card_qfpoly_gt1
in_qpoly_comp_horner(p q : {poly R}) : in_qpoly h (p \Po q) = (map_poly (qpolyC h) p).[in_qpoly h q]. Proof. have hQM := monic_mk_monic h. rewrite comp_polyE /map_poly poly_def horner_sum /=. apply: val_inj. rewrite /= rmodp_sum // poly_of_qpoly_sum. apply: eq_bigr => i _. rewrite !hornerE /in_qpoly /=. rewrite mul_polyC // !rmodpZ //=. by rewrite poly_of_qpolyX /= rmodp_id // rmodpX // rmodp_id. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
in_qpoly_comp_horner
map_poly_div_inj: injective (map_poly (qpolyC h)). Proof. apply: map_inj_poly => [x y /val_eqP /eqP /polyC_inj //|]. by rewrite qpolyC0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
map_poly_div_inj
qfpoly_const(R : idomainType) (h : {poly R}) (hMI : monic_irreducible_poly h) : R -> {poly %/ h with hMI} := qpolyC h.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qfpoly_const
map_fpoly_div_inj(R : idomainType) (h : {poly R}) (hMI : monic_irreducible_poly h) : injective (map_poly (qfpoly_const hMI)). Proof. by apply: (@map_poly_div_inj R h). Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
map_fpoly_div_inj
qfpoly_splitting_field_type:= FinSplittingFieldType F {poly %/ h with hI}.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qfpoly_splitting_field_type
primitive_poly(p: {poly F}) := let v := #|{poly %/ p}|.-1 in [&& p \is monic, irreducibleb p, p %| 'X^v - 1 & [forall n : 'I_v, (p %| 'X^n - 1) ==> (n == 0%N :> nat)]].
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
primitive_poly
primitive_polyP(p : {poly F}) : reflect (let v := #|{poly %/ p}|.-1 in [/\ monic_irreducible_poly p, p %| 'X^v - 1 & forall n, 0 < n < v -> ~~ (p %| 'X^n - 1)]) (primitive_poly p). Proof. apply: (iffP and4P) => [[H1 H2 H3 /forallP H4] v|[[H1 H2] H3 H4]]; split => //. - by split => //; apply/irreducibleP. - move=> n /andP[n_gt0 nLv]; apply/negP => /(implyP (H4 (Ordinal nLv))) /=. by rewrite eqn0Ngt n_gt0. - by apply/irreducibleP. apply/forallP=> [] [[|n] Hn] /=; apply/implyP => pDX //. by case/negP: (H4 n.+1 Hn). Qed. Hypothesis Hh : primitive_poly h.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
primitive_polyP
primitive_mi: monic_irreducible_poly h. Proof. by case/primitive_polyP: Hh. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
primitive_mi
primitive_poly_in_qpoly_eq0p : (in_qpoly h p == 0) = (h %| p). Proof. have hM : h \is monic by case/and4P:Hh. have hMi : monic_irreducible_poly h by apply: primitive_mi. apply/eqP/idP => [/val_eqP /= | hDp]. by rewrite -Pdiv.IdomainMonic.modpE mk_monicE. by apply/val_eqP; rewrite /= -Pdiv.IdomainMonic.modpE mk_monicE. Qed. Local Notation qT := {poly %/ h with primitive_mi}.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
primitive_poly_in_qpoly_eq0
card_primitive_qpoly: #|{poly %/ h}|= #|F| ^ (size h).-1. Proof. by rewrite card_monic_qpoly ?primitive_mi. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
card_primitive_qpoly
qX_neq0: 'qX != 0 :> qT. Proof. apply/eqP => /val_eqP/=. by rewrite [rmodp _ _]qpolyXE ?polyX_eq0 //; case: primitive_mi. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_neq0
qX_in_unit: ('qX : qT) \in GRing.unit. Proof. by rewrite unitfE /= qX_neq0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_in_unit
gX: {unit qT} := FinRing.unit _ qX_in_unit.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
gX
dvdp_ordern : (h %| 'X^n - 1) = (gX ^+ n == 1)%g. Proof. have [hM hI] := primitive_mi. have eqr_add2r (r : nzRingType) (a b c : r) : (a + c == b + c) = (a == b). by apply/eqP/eqP => [H|->//]; rewrite -(addrK c a) H addrK. rewrite -val_eqE /= val_unitX /= -val_eqE /=. rewrite (poly_of_qpolyX) qpolyXE // mk_monicE //. rewrite -[in RHS](subrK 1 'X^n) rmodpD //. rewrite [rmodp 1 h]rmodp_small ?size_poly1 //. rewrite -[1%:P]add0r polyC1 /= eqr_add2r. by rewrite dvdpE /=; apply/rmodp_eq0P/eqP. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
dvdp_order
gX_order: #[gX]%g = (#|qT|).-1. Proof. have /primitive_polyP[Hp1 Hp2 Hp3] := Hh. set n := _.-1 in Hp2 Hp3 *. have n_gt0 : 0 < n by rewrite ltn_predRL card_qfpoly_gt1. have [hM hI] := primitive_mi. have gX_neq1 : gX != 1%g. apply/eqP/val_eqP/eqP/val_eqP=> /=. rewrite [X in X != _]qpolyXE /= //. by apply/eqP=> Hx1; have := @size_polyX F; rewrite Hx1 size_poly1. have Hx : (gX ^+ n)%g = 1%g by apply/eqP; rewrite -dvdp_order. have Hf i : 0 < i < n -> (gX ^+ i != 1)%g by rewrite -dvdp_order => /Hp3. have o_gt0 : 0 < #[gX]%g by rewrite order_gt0. have : n <= #[gX]%g. rewrite leqNgt; apply/negP=> oLx. have /Hf/eqP[] : 0 < #[gX]%g < n by rewrite o_gt0. by rewrite expg_order. case: ltngtP => nLo _ //. have: uniq (path.traject (mul gX) 1%g #[gX]%g). by apply/card_uniqP; rewrite path.size_traject -(eq_card (cycle_traject gX)). case: #[gX]%g o_gt0 nLo => //= n1 _ nLn1 /andP[/negP[]]. apply/path.trajectP; exists n.-1; first by rewrite prednK. rewrite -iterSr prednK // -[LHS]Hx. by elim: (n) => //= n2 <-; rewrite expgS. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
gX_order
gX_all: <[gX]>%g = [set: {unit qT}]%G. Proof. apply/eqP; rewrite eqEcard; apply/andP; split. by apply/subsetP=> i; rewrite inE. rewrite leq_eqVlt; apply/orP; left; apply/eqP. rewrite -orderE gX_order card_qfpoly -[in RHS](mk_monicE primitive_mi). rewrite -card_qpoly -(cardC1 (0 : {poly %/ h with primitive_mi})). rewrite cardsT card_sub. by apply: eq_card => x; rewrite [LHS]unitfE. Qed. Let pred_card_qT_gt0 : 0 < #|qT|.-1. Proof. by rewrite ltn_predRL card_qfpoly_gt1. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
gX_all
qlogp(p : qT) : nat := odflt (Ordinal pred_card_qT_gt0) (pick [pred i in 'I_ _ | ('qX ^+ i == p)]).
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogp
qlogp_ltp : qlogp p < #|qT|.-1. Proof. by rewrite /qlogp; case: pickP. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogp_lt
qlogp_qX(p : qT) : p != 0 -> 'qX ^+ (qlogp p) = p. Proof. move=> p_neq0. have Up : p \in GRing.unit by rewrite unitfE. pose gp : {unit qT}:= FinRing.unit _ Up. have /cyclePmin[i iLc iX] : gp \in <[gX]>%g by rewrite gX_all inE. rewrite gX_order in iLc. rewrite /qlogp; case: pickP => [j /eqP//|/(_ (Ordinal iLc))] /eqP[]. by have /val_eqP/eqP/= := iX; rewrite FinRing.val_unitX. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogp_qX
qX_order_card: 'qX ^+ (#|qT|).-1 = 1 :> qT. Proof. have /primitive_polyP [_ Hd _] := Hh. rewrite dvdp_order in Hd. have -> : 1 = val (1%g : {unit qT}) by []. by rewrite -(eqP Hd) val_unitX. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_order_card
qX_order_dvd(i : nat) : 'qX ^+ i = 1 :> qT -> (#|qT|.-1 %| i)%N. Proof. rewrite -gX_order cyclic.order_dvdn => Hd. by apply/eqP/val_inj; rewrite /= -Hd val_unitX. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_order_dvd
qlogp0: qlogp 0 = 0%N. Proof. rewrite /qlogp; case: pickP => //= x. by rewrite (expf_eq0 ('qX : qT)) (negPf qX_neq0) andbF. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogp0
qlogp1: qlogp 1 = 0%N. Proof. case: (qlogp 1 =P 0%N) => // /eqP log1_neq0. have := qlogp_lt 1; rewrite ltnNge => /negP[]. apply: dvdn_leq; first by rewrite lt0n. by rewrite qX_order_dvd // qlogp_qX ?oner_eq0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogp1
qlogp_eq0(q : qT) : (qlogp q == 0%N) = (q == 0) || (q == 1). Proof. case: (q =P 0) => [->|/eqP q_neq0]/=; first by rewrite qlogp0. case: (q =P 1) => [->|/eqP q_neq1]/=; first by rewrite qlogp1. rewrite /qlogp; case: pickP => [x|/(_ (Ordinal (qlogp_lt q)))] /=. by case: ((x : nat) =P 0%N) => // ->; rewrite expr0 eq_sym (negPf q_neq1). by rewrite qlogp_qX // eqxx. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogp_eq0
qX_exp_neq0i : 'qX ^+ i != 0 :> qT. Proof. by rewrite expf_eq0 negb_and qX_neq0 orbT. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_exp_neq0
qX_exp_inji j : i < #|qT|.-1 -> j < #|qT|.-1 -> 'qX ^+ i = 'qX ^+ j :> qT -> i = j. Proof. wlog iLj : i j / (i <= j)%N => [Hw|] iL jL Hqx. case: (ltngtP i j)=> // /ltnW iLj; first by apply: Hw. by apply/sym_equal/Hw. suff ji_eq0 : (j - i = 0)%N by rewrite -(subnK iLj) ji_eq0. case: ((j - i)%N =P 0%N) => // /eqP ji_neq0. have : j - i < #|qT|.-1 by apply: leq_ltn_trans (leq_subr _ _) jL. rewrite ltnNge => /negP[]. apply: dvdn_leq; first by rewrite lt0n. have HqXi : 'qX ^+ i != 0 :> qT by rewrite expf_eq0 (negPf qX_neq0) andbF. by apply/qX_order_dvd/(mulIf HqXi); rewrite mul1r -exprD subnK. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_exp_inj
powX_eq_modi j : i = j %[mod #|qT|.-1] -> 'qX ^+ i = 'qX ^+ j :> qT. Proof. set n := _.-1 => iEj. rewrite [i](divn_eq i n) [j](divn_eq j n) !exprD ![(_ * n)%N]mulnC. by rewrite !exprM !qX_order_card !expr1n !mul1r iEj. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
powX_eq_mod
qX_expKi : i < #|qT|.-1 -> qlogp ('qX ^+ i) = i. Proof. move=> iLF; apply: qX_exp_inj => //; first by apply: qlogp_lt. by rewrite qlogp_qX // expf_eq0 (negPf qX_neq0) andbF. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qX_expK
qlogpD(q1 q2 : qT) : q1 != 0 -> q2 != 0 ->qlogp (q1 * q2) = ((qlogp q1 + qlogp q2) %% #|qT|.-1)%N. Proof. move=> q1_neq0 q2_neq0. apply: qX_exp_inj; [apply: qlogp_lt => // | rewrite ltn_mod // |]. rewrite -[RHS]mul1r -(expr1n _ ((qlogp q1 + qlogp q2) %/ #|qT|.-1)). rewrite -qX_order_card -exprM mulnC -exprD -divn_eq exprD !qlogp_qX //. by rewrite mulf_eq0 negb_or q1_neq0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
qlogpD
plogp(p q : {poly F}) := if boolP (primitive_poly p) is AltTrue Hh then qlogp ((in_qpoly p q) : {poly %/ p with primitive_mi Hh}) else 0%N.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogp
plogp_lt(p q : {poly F}) : 2 < size p -> plogp p q < #|{poly %/ p}|.-1. Proof. move=> /ltnW size_gt1. rewrite /plogp. case (boolP (primitive_poly p)) => // Hh; first by apply: qlogp_lt. by rewrite ltn_predRL (card_finNzRing_gt1 {poly %/ p}). Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogp_lt
plogp_X(p q : {poly F}) : 2 < size p -> primitive_poly p -> ~~ (p %| q) -> p %| q - 'X ^+ plogp p q. Proof. move=> sp_gt2 Hh pNDq. rewrite /plogp. case (boolP (primitive_poly p)) => // Hh'; last by case/negP: Hh'. have pM : p \is monic by case/and4P: Hh'. have pMi : monic_irreducible_poly p by apply: primitive_mi. set q' : {poly %/ p with primitive_mi Hh'} := in_qpoly p q. apply/modp_eq0P; rewrite modpD modpN; apply/eqP; rewrite subr_eq0; apply/eqP. rewrite !Pdiv.IdomainMonic.modpE //=. suff /val_eqP/eqP/= : 'qX ^+ qlogp q' = q'. rewrite /= [X in rmodp _ X]mk_monicE // => <-. by rewrite poly_of_qpolyX /= mk_monicE // [rmodp 'X p]rmodp_small ?size_polyX. apply: qlogp_qX => //. apply/eqP=> /val_eqP/eqP. rewrite /= mk_monicE // => /rmodp_eq0P; rewrite -dvdpE => pDq. by case/negP: pNDq. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogp_X
plogp0(p : {poly F}) : 2 < size p -> plogp p 0 = 0%N. Proof. move=> sp_gt2; rewrite /plogp; case (boolP (primitive_poly p)) => // i. by rewrite in_qpoly0 qlogp0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogp0
plogp1(p : {poly F}) : 2 < size p -> plogp p 1 = 0%N. Proof. move=> sp_gt2; rewrite /plogp; case (boolP (primitive_poly p)) => // i. suff->: in_qpoly p 1 = 1 by apply: qlogp1. apply/val_eqP/eqP; apply: in_qpoly_small. rewrite mk_monicE ?size_poly1 ?(leq_trans _ sp_gt2) //. by apply: primitive_mi. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogp1
plogp_div_eq0(p q : {poly F}) : 2 < size p -> (p %| q) -> plogp p q = 0%N. Proof. move=> sp_gt2; rewrite /plogp; case (boolP (primitive_poly p)) => // i pDq. suff-> : in_qpoly p q = 0 by apply: qlogp0. by apply/eqP; rewrite primitive_poly_in_qpoly_eq0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogp_div_eq0
plogpD(p q1 q2 : {poly F}) : 2 < size p -> primitive_poly p -> ~~ (p %| q1) -> ~~ (p %| q2) -> plogp p (q1 * q2) = ((plogp p q1 + plogp p q2) %% #|{poly %/ p}|.-1)%N. Proof. move=> sp_gt2 Pp pNDq1 pNDq2. rewrite /plogp; case (boolP (primitive_poly p)) => [|/negP//] i /=. have pmi := primitive_mi i. by rewrite rmorphM qlogpD //= primitive_poly_in_qpoly_eq0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrfun ssrbool eqtype ssrnat seq choice", "From mathcomp Require Import fintype tuple div bigop binomial finset finfun", "From mathcomp Require Import ssralg countalg finalg poly polydiv qpoly perm", "From mathcomp Require Import fingroup falgebra fieldext finfield galois", "From mathcomp Require Import finalg zmodp matrix vector" ]
field/qfpoly.v
plogpD
separable_poly{R : idomainType} (p : {poly R}) := coprimep p p^`().
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_poly
separable_poly_unlockable:= Unlockable separable_poly.unlock.
Canonical
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_poly_unlockable
separable_poly_neq0p : separable p -> p != 0. Proof. by apply: contraTneq => ->; rewrite unlock deriv0 coprime0p eqp01. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_poly_neq0
poly_square_freePp : (forall u v, u * v %| p -> coprimep u v) <-> (forall u, size u != 1 -> ~~ (u ^+ 2 %| p)). Proof. split=> [sq'p u | sq'p u v dvd_uv_p]. by apply: contra => /sq'p; rewrite coprimepp. rewrite coprimep_def (contraLR (sq'p _)) // (dvdp_trans _ dvd_uv_p) //. by rewrite dvdp_mul ?dvdp_gcdl ?dvdp_gcdr. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
poly_square_freeP
separable_polyP{p} : reflect [/\ forall u v, u * v %| p -> coprimep u v & forall u, u %| p -> 1 < size u -> u^`() != 0] (separable p). Proof. apply: (iffP idP) => [sep_p | [sq'p nz_der1p]]. split=> [u v | u u_dv_p]; last first. apply: contraTneq => u'0; rewrite unlock in sep_p; rewrite -leqNgt -(eqnP sep_p). rewrite dvdp_leq -?size_poly_eq0 ?(eqnP sep_p) // dvdp_gcd u_dv_p. have /dvdpZr <-: lead_coef u ^+ scalp p u != 0 by rewrite lcn_neq0. by rewrite -derivZ -Pdiv.Idomain.divpK //= derivM u'0 mulr0 addr0 dvdp_mull. rewrite Pdiv.Idomain.dvdp_eq mulrCA mulrA; set c := _ ^+ _ => /eqP Dcp. have nz_c: c != 0 by rewrite lcn_neq0. move: sep_p; rewrite coprimep_sym unlock -(coprimepZl _ _ nz_c). rewrite -(coprimepZr _ _ nz_c) -derivZ Dcp derivM coprimepMl. by rewrite coprimep_addl_mul !coprimepMr -andbA => /and4P[]. rewrite unlock coprimep_def eqn_leq size_poly_gt0; set g := gcdp _ _. have nz_g: g != 0. rewrite -dvd0p dvdp_gcd -(mulr0 0); apply/nandP; left. by have /poly_square_freeP-> := sq'p; rewrite ?size_poly0. have [g_p]: g %| p /\ g %| p^`() by rewrite dvdp_gcdr ?dvdp_gcdl. pose c := lead_coef g ^+ scalp p g; have nz_c: c != 0 by rewrite lcn_neq0. have Dcp: c *: p = p %/ g * g by rewrite Pdiv.Idomain.divpK. rewrite nz_g andbT leqNgt -(dvdpZr _ _ nz_c) -derivZ Dcp derivM. rewrite dvdp_addr; last by rewrite dvdp_mull. rewrite Gauss_dvdpr; last by rewrite sq'p // mulrC -Dcp dvdpZl. by apply: contraL => /nz_der1p nz_g'; rewrite gtNdvdp ?nz_ ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_polyP
separable_coprimep u v : separable p -> u * v %| p -> coprimep u v. Proof. by move=> /separable_polyP[sq'p _] /sq'p. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_coprime
separable_nosquarep u k : separable p -> 1 < k -> size u != 1 -> (u ^+ k %| p) = false. Proof. move=> /separable_polyP[/poly_square_freeP sq'p _] /subnKC <- /sq'p. by apply: contraNF; apply: dvdp_trans; rewrite exprD dvdp_mulr. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_nosquare
separable_deriv_eq0p u : separable p -> u %| p -> 1 < size u -> (u^`() == 0) = false. Proof. by move=> /separable_polyP[_ nz_der1p] u_p /nz_der1p/negPf->. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_deriv_eq0
dvdp_separablep q : q %| p -> separable p -> separable q. Proof. move=> /(dvdp_trans _)q_dv_p /separable_polyP[sq'p nz_der1p]. by apply/separable_polyP; split=> [u v /q_dv_p/sq'p | u /q_dv_p/nz_der1p]. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
dvdp_separable
separable_mulp q : separable (p * q) = [&& separable p, separable q & coprimep p q]. Proof. apply/idP/and3P => [sep_pq | [sep_p sep_q co_pq]]. rewrite !(dvdp_separable _ sep_pq) ?dvdp_mulIr ?dvdp_mulIl //. by rewrite (separable_coprime sep_pq). rewrite unlock in sep_p sep_q *. rewrite derivM coprimepMl {1}addrC mulrC !coprimep_addl_mul. by rewrite !coprimepMr (coprimep_sym q p) co_pq !andbT; apply/andP. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_mul
eqp_separablep q : p %= q -> separable p = separable q. Proof. by case/andP=> p_q q_p; apply/idP/idP=> /dvdp_separable->. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
eqp_separable
separable_rootp x : separable (p * ('X - x%:P)) = separable p && ~~ root p x. Proof. rewrite separable_mul; apply: andb_id2l => seq_p. by rewrite unlock derivXsubC coprimep1 coprimep_XsubC. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_root
separable_prod_XsubC(r : seq R) : separable (\prod_(x <- r) ('X - x%:P)) = uniq r. Proof. elim: r => [|x r IH]; first by rewrite big_nil unlock /separable_poly coprime1p. by rewrite big_cons mulrC separable_root IH root_prod_XsubC andbC. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_prod_XsubC
make_separablep : p != 0 -> separable (p %/ gcdp p p^`()). Proof. set g := gcdp p p^`() => nz_p; apply/separable_polyP. have max_dvd_u (u : {poly R}): 1 < size u -> exists k, ~~ (u ^+ k %| p). move=> u_gt1; exists (size p); rewrite gtNdvdp // polySpred //. by rewrite -(ltn_subRL 1) subn1 size_exp leq_pmull // -(subnKC u_gt1). split=> [|u u_pg u_gt1]; last first. apply/eqP=> u'0 /=; have [k /negP[]] := max_dvd_u u u_gt1. elim: k => [|k IHk]; first by rewrite dvd1p. suffices: u ^+ k.+1 %| (p %/ g) * g. by rewrite Pdiv.Idomain.divpK ?dvdp_gcdl // dvdpZr ?lcn_neq0. rewrite exprS dvdp_mul // dvdp_gcd IHk //=. suffices: u ^+ k %| (p %/ u ^+ k * u ^+ k)^`(). by rewrite Pdiv.Idomain.divpK // derivZ dvdpZr ?lcn_neq0. by rewrite !derivCE u'0 mul0r mul0rn mulr0 addr0 dvdp_mull. have pg_dv_p: p %/ g %| p by rewrite divp_dvd ?dvdp_gcdl. apply/poly_square_freeP=> u; rewrite neq_ltn ltnS leqn0 size_poly_eq0. case/predU1P=> [-> | /max_dvd_u[k]]. by apply: contra nz_p; rewrite expr0n -dvd0p => /dvdp_trans->. apply: contra => u2_dv_pg; case: k; [by rewrite dvd1p | elim=> [|n IHn]]. exact: dvdp_trans (dvdp_mulr _ _) (dvdp_trans u2_dv_pg pg_dv_p). suff: u ^+ n.+2 %| (p %/ g) * g. by rewrite Pdiv.Idomain.divpK ?dvdp_gcdl // dvdpZr ?lcn_neq0. rewrite -add2n exprD dvdp_mul // dvdp_gcd. rewrite (dvdp_trans _ IHn) ?exprS ?dvdp_mull //=. suff: u ^+ n %| ((p %/ u ^+ n.+1) * u ^+ n.+1)^`(). by rewrite Pdiv.Idomain.divpK // derivZ dvdpZr ?lcn_neq0. by rewrite !derivCE dvdp_add // -1?mul ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
make_separable
separable_map(F : fieldType) (R : idomainType) (f : {rmorphism F -> R}) (p : {poly F}) : separable_poly (map_poly f p) = separable_poly p. Proof. by rewrite unlock deriv_map /coprimep -gcdp_map size_map_poly. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_map
large_field_PETq : root (q ^ iota) y -> separable_poly q -> exists2 r, r != 0 & forall t (z := iota t * y - x), ~~ root r (iota t) -> inFz z x /\ inFz z y. Proof. move=> qy_0 sep_q; have nz_q := separable_poly_neq0 sep_q. have /factor_theorem[q0 Dq] := qy_0. set p1 := p ^ iota \Po ('X + x%:P); set q1 := q0 \Po ('X + y%:P). have nz_p1: p1 != 0. apply: contraNneq nz_p => /(canRL (fun r => comp_polyXaddC_K r _))/eqP. by rewrite comp_poly0 map_poly_eq0. have{sep_q} nz_q10: q1.[0] != 0. move: sep_q; rewrite -(separable_map iota) Dq separable_root => /andP[_]. by rewrite horner_comp !hornerE. have nz_q1: q1 != 0 by apply: contraNneq nz_q10 => ->; rewrite horner0. pose p2 := p1 ^ polyC \Po ('X * 'Y); pose q2 := q1 ^ polyC. have /Bezout_coprimepP[[u v]]: coprimep p2 q2. rewrite coprimep_def eqn_leq leqNgt andbC size_poly_gt0 gcdp_eq0 poly_XmY_eq0. by rewrite map_polyC_eq0 (negPf nz_p1) -resultant_eq0 div_annihilant_neq0. rewrite -size_poly_eq1 => /size_poly1P[r nzr Dr]; exists r => {nzr}// t z nz_rt. have [r1 nz_r1 r1z_0]: algebraicOver iota z. apply/algebraic_sub; last by exists p. by apply: algebraic_mul; [apply: algebraic_id | exists q]. pose Fz := subFExtend iota z r1; pose kappa : Fz -> L := subfx_inj. pose kappa' := inj_subfx iota z r1. have /eq_map_poly Diota: kappa \o kappa' =1 iota. by move=> w; rewrite /kappa /= subfx_inj_eval // map_polyC hornerC. suffices [y3]: exists y3, y = kappa y3. have [q3 ->] := subfxE y3; rewrite /kappa subfx_inj_eval // => Dy. split ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
large_field_PET
pchar0_PET(q : {poly F}) : q != 0 -> root (q ^ iota) y -> [pchar F] =i pred0 -> exists n, let z := y *+ n - x in inFz z x /\ inFz z y. Proof. move=> nz_q qy_0 /pcharf0P pcharF0. without loss{nz_q} sep_q: q qy_0 / separable_poly q. move=> IHq; apply: IHq (make_separable nz_q). have /dvdpP[q1 Dq] := dvdp_gcdl q q^`(). rewrite {1}Dq mulpK ?gcdp_eq0; last by apply/nandP; left. have [n [r nz_ry Dr]] := multiplicity_XsubC (q ^ iota) y. rewrite map_poly_eq0 nz_q /= in nz_ry. case: n => [|n] in Dr; first by rewrite Dr mulr1 (negPf nz_ry) in qy_0. have: ('X - y%:P) ^+ n.+1 %| q ^ iota by rewrite Dr dvdp_mulIr. rewrite Dq rmorphM /= gcdp_map -(eqp_dvdr _ (gcdp_mul2l _ _ _)) -deriv_map Dr. rewrite dvdp_gcd derivM deriv_exp derivXsubC mul1r !mulrA dvdp_mulIr /=. rewrite mulrDr mulrA dvdp_addr ?dvdp_mulIr // exprS -scaler_nat -!scalerAr. rewrite dvdpZr -?(rmorph_nat iota) ?fmorph_eq0 ?pcharF0 //. rewrite mulrA dvdp_mul2r ?expf_neq0 ?polyXsubC_eq0 //. by rewrite Gauss_dvdpl ?dvdp_XsubCl // coprimep_sym coprimep_XsubC. have [r nz_r PETxy] := large_field_PET qy_0 sep_q. pose ts := mkseq (fun n => iota n%:R) (size r). have /(max_ring_poly_roots nz_r)/=/implyP: uniq_roots ts. rewrite uniq_rootsE mkseq_uniq // => m n eq_mn; apply/eqP; rewrite eqn_leq. wlog suffices: m n eq_mn / m <= n by move=> IHmn; rewrite !IHmn. move/fmorph_inj/eqP: eq_mn; rewrite -subr_eq0 leqNgt; apply: contraL => lt_mn. by rewrite -natrB ?(ltnW lt_mn) // pcharF0 -lt0n subn_gt0. rewrite size_m ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
pchar0_PET
char0_PET:= (pchar0_PET) (only parsing).
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
char0_PET
Derivation: bool := all2rel (fun u v => D (u * v) == D u * v + u * D v) (vbasis K). Hypothesis derD : Derivation.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation
Derivation_mul: {in K &, forall u v, D (u * v) = D u * v + u * D v}. Proof. move=> u v /coord_vbasis-> /coord_vbasis->. rewrite !(mulr_sumr, linear_sum) -big_split; apply: eq_bigr => /= j _. rewrite !mulr_suml linear_sum -big_split; apply: eq_bigr => /= i _. rewrite !(=^~ scalerAl, linearZZ) -!scalerAr linearZZ -!scalerDr !scalerA /=. by congr (_ *: _); apply/eqP/(allrelP derD); exact: memt_nth. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_mul
Derivation_mul_poly(Dp := map_poly D) : {in polyOver K &, forall p q, Dp (p * q) = Dp p * q + p * Dp q}. Proof. move=> p q Kp Kq; apply/polyP=> i; rewrite {}/Dp coefD coef_map /= !coefM. rewrite linear_sum -big_split; apply: eq_bigr => /= j _. by rewrite !{1}coef_map Derivation_mul ?(polyOverP _). Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_mul_poly
DerivationSE K D : (K <= E)%VS -> Derivation E D -> Derivation K D. Proof. move/subvP=> sKE derD; apply/allrelP=> x y Kx Ky; apply/eqP. by rewrite (Derivation_mul derD) ?sKE // vbasis_mem. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
DerivationS
Derivation1: D 1 = 0. Proof. apply: (addIr (D (1 * 1))); rewrite add0r {1}mul1r. by rewrite (Derivation_mul derD) ?mem1v // mulr1 mul1r. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation1
Derivation_scalarx : x \in 1%VS -> D x = 0. Proof. by case/vlineP=> y ->; rewrite linearZ /= Derivation1 scaler0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_scalar
Derivation_expx m : x \in E -> D (x ^+ m) = x ^+ m.-1 *+ m * D x. Proof. move=> Ex; case: m; first by rewrite expr0 mulr0n mul0r Derivation1. elim=> [|m IHm]; first by rewrite mul1r. rewrite exprS (Derivation_mul derD) //; last by apply: rpredX. by rewrite mulrC IHm mulrA mulrnAr -exprS -mulrDl. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_exp
Derivation_hornerp x : p \is a polyOver E -> x \in E -> D p.[x] = (map_poly D p).[x] + p^`().[x] * D x. Proof. move=> Ep Ex; elim/poly_ind: p Ep => [|p c IHp] /polyOverP EpXc. by rewrite !(raddf0, horner0) mul0r add0r. have Ep: p \is a polyOver E. by apply/polyOverP=> i; have:= EpXc i.+1; rewrite coefD coefMX coefC addr0. have->: map_poly D (p * 'X + c%:P) = map_poly D p * 'X + (D c)%:P. apply/polyP=> i; rewrite !(coefD, coefMX, coef_map) /= linearD /= !coefC. by rewrite !(fun_if D) linear0. rewrite derivMXaddC !hornerE mulrDl mulrAC addrAC linearD /=; congr (_ + _). by rewrite addrCA -mulrDl -IHp // addrC (Derivation_mul derD) ?rpred_horner. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_horner
separable_elementU x := separable_poly (minPoly U x).
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_element
separable_elementP: reflect (exists f, [/\ f \is a polyOver K, root f x & separable_poly f]) (separable_element K x). Proof. apply: (iffP idP) => [sep_x | [f [Kf /(minPoly_dvdp Kf)/dvdpP[g ->]]]]. by exists (minPoly K x); rewrite minPolyOver root_minPoly. by rewrite separable_mul => /and3P[]. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_elementP
base_separable: x \in K -> separable_element K x. Proof. move=> Kx; apply/separable_elementP; exists ('X - x%:P). by rewrite polyOverXsubC root_XsubC unlock !derivCE coprimep1. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
base_separable
separable_nz_der: separable_element K x = ((minPoly K x)^`() != 0). Proof. rewrite /separable_element unlock. apply/idP/idP=> [|nzPx']. by apply: contraTneq => ->; rewrite coprimep0 -size_poly_eq1 size_minPoly. have gcdK : gcdp (minPoly K x) (minPoly K x)^`() \in polyOver K. by rewrite gcdp_polyOver ?polyOver_deriv // minPolyOver. rewrite -gcdp_eqp1 -size_poly_eq1 -dvdp1. have /orP[/andP[_]|/andP[]//] := minPoly_irr gcdK (dvdp_gcdl _ _). rewrite dvdp_gcd dvdpp /= => /(dvdp_leq nzPx')/leq_trans/(_ (size_poly _ _)). by rewrite size_minPoly ltnn. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_nz_der
separablePn_pchar: reflect (exists2 p, p \in [pchar L] & exists2 g, g \is a polyOver K & minPoly K x = g \Po 'X^p) (~~ separable_element K x). Proof. rewrite separable_nz_der negbK; set f := minPoly K x. apply: (iffP eqP) => [f'0 | [p Hp [g _ ->]]]; last first. by rewrite deriv_comp derivXn -scaler_nat (pcharf0 Hp) scale0r mulr0. pose n := adjoin_degree K x; have sz_f: size f = n.+1 := size_minPoly K x. have fn1: f`_n = 1 by rewrite -(monicP (monic_minPoly K x)) lead_coefE sz_f. have dimKx: (adjoin_degree K x)%:R == 0 :> L. by rewrite -(coef0 _ n.-1) -f'0 coef_deriv fn1. have /natf0_pchar[// | p pcharLp] := dimKx. have /dvdnP[r Dn]: (p %| n)%N by rewrite (dvdn_pcharf pcharLp). exists p => //; exists (\poly_(i < r.+1) f`_(i * p)). by apply: polyOver_poly => i _; rewrite (polyOverP _) ?minPolyOver. rewrite comp_polyE size_poly_eq -?Dn ?fn1 ?oner_eq0 //. have pr_p := pcharf_prime pcharLp; have p_gt0 := prime_gt0 pr_p. apply/polyP=> i; rewrite coef_sum. have [[{}i ->] | p'i] := altP (@dvdnP p i); last first. rewrite big1 => [|j _]; last first. rewrite coefZ -exprM coefXn [_ == _](contraNF _ p'i) ?mulr0 // => /eqP->. by rewrite dvdn_mulr. rewrite (dvdn_pcharf pcharLp) in p'i; apply: mulfI p'i _ _ _. by rewrite mulr0 mulr_natl; case: i => // i; rewrite -coef_deriv f'0 coef0. have [ltri | leir] := leqP r.+1 i. rewrite nth_default ?sz_f ?Dn ?ltn_pmul2r ?big1 // => j _. rewrite coefZ -exprM coefXn mulnC gtn_eqF ?mulr0 //. by rewrite ltn_pmul2l ?(leq_tr ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separablePn_pchar
separable_root_der: separable_element K x (+) root (minPoly K x)^`() x. Proof. have KpKx': _^`() \is a polyOver K := polyOver_deriv (minPolyOver K x). rewrite separable_nz_der addNb (root_small_adjoin_poly KpKx') ?addbb //. by rewrite (leq_trans (size_poly _ _)) ?size_minPoly. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_root_der
Derivation_separableD : Derivation <<K; x>> D -> separable_element K x -> D x = - (map_poly D (minPoly K x)).[x] / (minPoly K x)^`().[x]. Proof. move=> derD sepKx; have:= separable_root_der; rewrite {}sepKx -sub0r => nzKx'x. apply: canRL (mulfK nzKx'x) (canRL (addrK _) _); rewrite mulrC addrC. rewrite -(Derivation_horner derD) ?minPolyxx ?linear0 //. exact: polyOverSv sKxK _ (minPolyOver _ _). Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_separable
Definition_ := @GRing.isZmodMorphism.Build _ _ body (extendDerivation_zmod_morphism_subproof E). HB.instance Definition _ := @GRing.isScalable.Build _ _ _ _ body (extendDerivation_scalable_subproof E). Let extendDerivationLinear := Eval hnf in (body : {linear _ -> _}).
HB.instance
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Definition
extendDerivation: 'End(L) := linfun extendDerivationLinear.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
extendDerivation
extendDerivation_idy : y \in K -> extendDerivation K y = D y. Proof. move=> yK; rewrite lfunE /= Fadjoin_polyC // derivC map_polyC hornerC. by rewrite horner0 mul0r addr0. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
extendDerivation_id
extendDerivation_hornerp : p \is a polyOver K -> separable_element K x -> extendDerivation K p.[x] = (map_poly D p).[x] + p^`().[x] * Dx K. Proof. move=> Kp sepKx; have:= separable_root_der; rewrite {}sepKx /= => nz_pKx'x. rewrite [in RHS](divp_eq p (minPoly K x)) lfunE /= Fadjoin_poly_mod ?raddfD //=. rewrite (Derivation_mul_poly derD) ?divp_polyOver ?minPolyOver //. rewrite derivM !{1}hornerD !{1}hornerM minPolyxx !{1}mulr0 !{1}add0r. rewrite mulrDl addrA [_ + (_ * _ * _)]addrC {2}/Dx -mulrA -/Dx. by rewrite [_ / _]mulrC (mulVKf nz_pKx'x) mulrN addKr. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
extendDerivation_horner
extendDerivationP: separable_element K x -> Derivation <<K; x>> (extendDerivation K). Proof. move=> sep; apply/allrelP=> u v /vbasis_mem Hu /vbasis_mem Hv; apply/eqP. rewrite -(Fadjoin_poly_eq Hu) -(Fadjoin_poly_eq Hv) -hornerM. rewrite !{1}extendDerivation_horner ?{1}rpredM ?Fadjoin_polyOver //. rewrite (Derivation_mul_poly derD) ?Fadjoin_polyOver //. rewrite derivM !{1}hornerD !{1}hornerM !{1}mulrDl !{1}mulrDr -!addrA. congr (_ + _); rewrite [Dx K]lock -!{1}mulrA !{1}addrA; congr (_ + _). by rewrite addrC; congr (_ * _ + _); rewrite mulrC. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
extendDerivationP
Derivation_separableP: reflect (forall D, Derivation <<K; x>> D -> K <= lker D -> <<K; x>> <= lker D)%VS (separable_element K x). Proof. apply: (iffP idP) => [sepKx D derD /subvP DK_0 | derKx_0]. have{} DK_0 q: q \is a polyOver K -> map_poly D q = 0. move=> /polyOverP Kq; apply/polyP=> i; apply/eqP. by rewrite coef0 coef_map -memv_ker DK_0. apply/subvP=> _ /Fadjoin_polyP[p Kp ->]; rewrite memv_ker. rewrite (Derivation_horner derD) ?(polyOverSv sKxK) //. rewrite (Derivation_separable derD sepKx) !DK_0 ?minPolyOver //. by rewrite horner0 oppr0 mul0r mulr0 addr0. apply: wlog_neg; rewrite {1}separable_nz_der negbK => /eqP pKx'_0. pose Df := fun y => (Fadjoin_poly K x y)^`().[x]. have Dlin: linear Df. move=> a u v; rewrite /Df linearP /= -mul_polyC derivD derivM derivC. by rewrite mul0r add0r hornerD hornerM hornerC -scalerAl mul1r. pose DlinM := GRing.isLinear.Build _ _ _ _ Df Dlin. pose DL : {linear _ -> _} := HB.pack Df DlinM. pose D := linfun DL; apply: base_separable. have DK_0: (K <= lker D)%VS. apply/subvP=> v Kv; rewrite memv_ker lfunE /= /Df Fadjoin_polyC //. by rewrite derivC horner0. have Dder: Derivation <<K; x>> D. apply/allrelP=> u v /vbasis_mem Kx_u /vbasis_mem Kx_v; apply/eqP. rewrite !lfunE /= /Df; set Px := Fadjoin_poly K x. set Px_u := Px u; rewrite -(Fadjoin_poly_eq Kx_u) -/Px -/Px_u. set Px_v := Px v; rewrite -(Fadjoin_poly_eq Kx_v) -/Px -/Px_v. rewrite -!hornerM -hornerD -derivM. rewrite /Px Fadjoin_poly_mod ?rpredM ?Fadjoin_polyOve ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Derivation_separableP
separablePn:= (separablePn_pchar) (only parsing). Arguments separable_elementP {K x}.
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separablePn
separable_elementSK E x : (K <= E)%VS -> separable_element K x -> separable_element E x. Proof. move=> sKE /separable_elementP[f [fK rootf sepf]]; apply/separable_elementP. by exists f; rewrite (polyOverSv sKE). Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_elementS
adjoin_separableP{K x} : reflect (forall y, y \in <<K; x>>%VS -> separable_element K y) (separable_element K x). Proof. apply: (iffP idP) => [sepKx | -> //]; last exact: memv_adjoin. move=> _ /Fadjoin_polyP[q Kq ->]; apply/Derivation_separableP=> D derD DK_0. apply/subvP=> _ /Fadjoin_polyP[p Kp ->]. rewrite memv_ker -(extendDerivation_id x D (mempx_Fadjoin _ Kp)). have sepFyx: (separable_element <<K; q.[x]>> x). by apply: (separable_elementS (subv_adjoin _ _)). have KyxEqKx: (<< <<K; q.[x]>>; x>> = <<K; x>>)%VS. apply/eqP; rewrite eqEsubv andbC adjoinSl ?subv_adjoin //=. apply/FadjoinP/andP; rewrite memv_adjoin andbT. by apply/FadjoinP/andP; rewrite subv_adjoin mempx_Fadjoin. have /[!KyxEqKx] derDx := extendDerivationP derD sepFyx. rewrite -horner_comp (Derivation_horner derDx) ?memv_adjoin //; last first. by apply: (polyOverSv (subv_adjoin _ _)); apply: polyOver_comp. set Dx_p := map_poly _; have Dx_p_0 t: t \is a polyOver K -> (Dx_p t).[x] = 0. move/polyOverP=> Kt; congr (_.[x] = 0): (horner0 x); apply/esym/polyP => i. have /eqP Dti_0: D t`_i == 0 by rewrite -memv_ker (subvP DK_0) ?Kt. by rewrite coef0 coef_map /= {1}extendDerivation_id ?subvP_adjoin. rewrite (Derivation_separable derDx sepKx) -/Dx_p Dx_p_0 ?polyOver_comp //. by rewrite add0r mulrCA Dx_p_0 ?minPolyOver ?oppr0 ?mul0r. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
adjoin_separableP
separable_exponent_pcharK x : exists n, [pchar L].-nat n && separable_element K (x ^+ n). Proof. pose d := adjoin_degree K x; move: {2}d.+1 (ltnSn d) => n. elim: n => // n IHn in x @d *; rewrite ltnS => le_d_n. have [[p pcharLp]|] := altP (separablePn_pchar K x); last by rewrite negbK; exists 1. case=> g Kg defKx; have p_pr := pcharf_prime pcharLp. suffices /IHn[m /andP[pcharLm sepKxpm]]: adjoin_degree K (x ^+ p) < n. by exists (p * m)%N; rewrite pnatM pnatE // pcharLp pcharLm exprM. apply: leq_trans le_d_n; rewrite -ltnS -!size_minPoly. have nzKx: minPoly K x != 0 by rewrite monic_neq0 ?monic_minPoly. have nzg: g != 0 by apply: contra_eqN defKx => /eqP->; rewrite comp_poly0. apply: leq_ltn_trans (dvdp_leq nzg _) _. by rewrite minPoly_dvdp // rootE -hornerXn -horner_comp -defKx minPolyxx. rewrite (polySpred nzKx) ltnS defKx size_comp_poly size_polyXn /=. suffices g_gt1: 1 < size g by rewrite -(subnKC g_gt1) ltn_Pmulr ?prime_gt1. apply: contra_eqT (size_minPoly K x); rewrite defKx -leqNgt => /size1_polyC->. by rewrite comp_polyC size_polyC; case: (_ != 0). Qed. #[deprecated(since="mathcomp 2.4.0", note="Use separable_exponent_pchar instead.")]
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_exponent_pchar
separable_exponent:= (separable_exponent_pchar) (only parsing).
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_exponent
pcharf0_separableK : [pchar L] =i pred0 -> forall x, separable_element K x. Proof. move=> pcharL0 x; have [n /andP[pcharLn]] := separable_exponent_pchar K x. by rewrite (pnat_1 pcharLn (sub_in_pnat _ pcharLn)) // => p _; rewrite pcharL0. Qed. #[deprecated(since="mathcomp 2.4.0", note="Use pcharf0_separable instead.")]
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
pcharf0_separable
charf0_separable:= (pcharf0_separable) (only parsing).
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
charf0_separable
pcharf_p_separableK x e p : p \in [pchar L] -> separable_element K x = (x \in <<K; x ^+ (p ^ e.+1)>>%VS). Proof. move=> pcharLp; apply/idP/idP=> [sepKx | /Fadjoin_poly_eq]; last first. set m := p ^ _; set f := Fadjoin_poly K _ x => Dx; apply/separable_elementP. have mL0: m%:R = 0 :> L by apply/eqP; rewrite -(dvdn_pcharf pcharLp) dvdn_exp. exists ('X - (f \Po 'X^m)); split. - by rewrite rpredB ?polyOver_comp ?rpredX ?polyOverX ?Fadjoin_polyOver. - by rewrite rootE !hornerE horner_comp hornerXn Dx subrr. rewrite unlock !(derivE, deriv_comp) -mulr_natr -rmorphMn /= mL0. by rewrite !mulr0 subr0 coprimep1. without loss{e} ->: e x sepKx / e = 0. move=> IH; elim: {e}e.+1 => [|e]; [exact: memv_adjoin | apply: subvP]. apply/FadjoinP/andP; rewrite subv_adjoin expnSr exprM (IH 0) //. by have /adjoin_separableP-> := sepKx; rewrite ?rpredX ?memv_adjoin. set K' := <<K; x ^+ p>>%VS; have sKK': (K <= K')%VS := subv_adjoin _ _. pose q := minPoly K' x; pose g := 'X^p - (x ^+ p)%:P. have [K'g]: g \is a polyOver K' /\ q \is a polyOver K'. by rewrite minPolyOver rpredB ?rpredX ?polyOverX // polyOverC memv_adjoin. have /dvdpP[c Dq]: 'X - x%:P %| q by rewrite dvdp_XsubCl root_minPoly. have co_c_g: coprimep c g. have pcharPp: p \in [pchar {poly L}] := rmorph_pchar polyC pcharLp. rewrite /g polyC_exp -!(pFrobenius_autE pcharPp) -rmorphB coprimep_expr //. have: separable_poly q := separable_elementS sKK' sepKx. by rewrite Dq separable_mul => /and3P[]. have{g K'g co_c_g} /size_poly1P[a nz ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
pcharf_p_separable
charf_p_separable:= (pcharf_p_separable) (only parsing).
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
charf_p_separable
pcharf_n_separableK x n : [pchar L].-nat n -> 1 < n -> separable_element K x = (x \in <<K; x ^+ n>>%VS). Proof. rewrite -pi_pdiv; set p := pdiv n => pcharLn pi_n_p. have pcharLp: p \in [pchar L] := pnatPpi pcharLn pi_n_p. have <-: (n`_p)%N = n by rewrite -(eq_partn n (pcharf_eq pcharLp)) part_pnat_id. by rewrite p_part lognE -mem_primes pi_n_p -pcharf_p_separable. Qed. #[deprecated(since="mathcomp 2.4.0", note="Use pcharf_n_separable instead.")]
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
pcharf_n_separable
charf_n_separable:= (pcharf_n_separable) (only parsing).
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
charf_n_separable
purely_inseparable_elementU x := x ^+ ex_minn (separable_exponent_pchar <<U>> x) \in U.
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
purely_inseparable_element
purely_inseparable_elementP_pchar{K x} : reflect (exists2 n, [pchar L].-nat n & x ^+ n \in K) (purely_inseparable_element K x). Proof. rewrite /purely_inseparable_element. case: ex_minnP => n /andP[pcharLn /=]; rewrite subfield_closed => sepKxn min_xn. apply: (iffP idP) => [Kxn | [m pcharLm Kxm]]; first by exists n. have{min_xn}: n <= m by rewrite min_xn ?pcharLm ?base_separable. rewrite leq_eqVlt => /predU1P[-> // | ltnm]; pose p := pdiv m. have m_gt1: 1 < m by have [/leq_ltn_trans->] := andP pcharLn. have pcharLp: p \in [pchar L] by rewrite (pnatPpi pcharLm) ?pi_pdiv. have [/p_natP[em Dm] /p_natP[en Dn]]: p.-nat m /\ p.-nat n. by rewrite -!(eq_pnat _ (pcharf_eq pcharLp)). rewrite Dn Dm ltn_exp2l ?prime_gt1 ?pdiv_prime // in ltnm. rewrite -(Fadjoin_idP Kxm) Dm -(subnKC ltnm) addSnnS expnD exprM -Dn. by rewrite -pcharf_p_separable. Qed. #[deprecated(since="mathcomp 2.4.0", note="Use purely_inseparable_elementP_pchar instead.")]
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
purely_inseparable_elementP_pchar
purely_inseparable_elementP:= (purely_inseparable_elementP_pchar) (only parsing).
Notation
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
purely_inseparable_elementP
separable_inseparable_elementK x : separable_element K x && purely_inseparable_element K x = (x \in K). Proof. rewrite /purely_inseparable_element; case: ex_minnP => [[|m]] //=. rewrite subfield_closed; case: m => /= [-> //| m _ /(_ 1)/implyP/= insepKx]. by rewrite (negPf insepKx) (contraNF (@base_separable K x) insepKx). Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable_inseparable_element
base_inseparableK x : x \in K -> purely_inseparable_element K x. Proof. by rewrite -separable_inseparable_element => /andP[]. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
base_inseparable
sub_inseparableK E x : (K <= E)%VS -> purely_inseparable_element K x -> purely_inseparable_element E x. Proof. move/subvP=> sKE /purely_inseparable_elementP_pchar[n pcharLn /sKE Exn]. by apply/purely_inseparable_elementP_pchar; exists n. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
sub_inseparable
finite_PET: K_is_large \/ exists z, (<< <<K; y>>; x>> = <<K; z>>)%VS. Proof. have [-> | /cyclic_or_large[|[a Dxa]]] := eqVneq x 0; first 2 [by left]. by rewrite addv0 subfield_closed; right; exists y. have [-> | /cyclic_or_large[|[b Dyb]]] := eqVneq y 0; first 2 [by left]. by rewrite addv0 subfield_closed; right; exists x. pose h0 (ij : 'I_a.+1 * 'I_b.+1) := x ^+ ij.1 * y ^+ ij.2. pose H := <<[set ij | h0 ij == 1%R]>>%G; pose h (u : coset_of H) := h0 (repr u). have h0M: {morph h0: ij1 ij2 / (ij1 * ij2)%g >-> ij1 * ij2}. by rewrite /h0 => [] [i1 j1] [i2 j2] /=; rewrite mulrACA -!exprD !expr_mod. have memH ij: (ij \in H) = (h0 ij == 1). rewrite /= gen_set_id ?inE //; apply/group_setP; rewrite inE [h0 _]mulr1. by split=> // ? ? /[!(inE, h0M)] /eqP-> /eqP->; rewrite mulr1. have nH ij: ij \in 'N(H)%g. by apply/(subsetP (cent_sub _))/centP=> ij1 _; congr (_, _); rewrite Zp_mulgC. have hE ij: h (coset H ij) = h0 ij. rewrite /h val_coset //; case: repr_rcosetP => ij1. by rewrite memH h0M => /eqP->; rewrite mul1r. have h1: h 1%g = 1 by rewrite /h repr_coset1 [h0 _]mulr1. have hM: {morph h: u v / (u * v)%g >-> u * v}. by do 2![move=> u; have{u} [? _ ->] := cosetP u]; rewrite -morphM // !hE h0M. have /cyclicP[w defW]: cyclic [set: coset_of H]. apply: field_mul_group_cyclic (in2W hM) _ => u _; have [ij _ ->] := cosetP u. by split=> [/eqP | -> //]; rewrite hE -memH => /coset_id. have Kw_h ij t: h0 ij = t -> t \in <<K; h w>>%VS. have /cycleP[k Dk]: coset H ij \in <[w]>%g by r ...
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
finite_PET
Primitive_Element_Theorem: exists z, (<< <<K; y>>; x>> = <<K; z>>)%VS. Proof. have /polyOver_subvs[p Dp]: minPoly K x \is a polyOver K := minPolyOver K x. have nz_pKx: minPoly K x != 0 by rewrite monic_neq0 ?monic_minPoly. have{nz_pKx} nz_p: p != 0 by rewrite Dp map_poly_eq0 in nz_pKx. have{Dp} px0: root (map_poly vsval p) x by rewrite -Dp root_minPoly. have [q0 [Kq0 q0y0 sepKq0]] := separable_elementP sepKy. have /polyOver_subvs[q Dq]: minPoly K y \is a polyOver K := minPolyOver K y. have qy0: root (map_poly vsval q) y by rewrite -Dq root_minPoly. have sep_pKy: separable_poly (minPoly K y). by rewrite (dvdp_separable _ sepKq0) ?minPoly_dvdp. have{sep_pKy} sep_q: separable_poly q by rewrite Dq separable_map in sep_pKy. have [r nz_r PETr] := large_field_PET nz_p px0 qy0 sep_q. have [[s [Us Ks /ltnW leNs]] | //] := finite_PET (size r). have{s Us leNs} /allPn[t {}/Ks Kt nz_rt]: ~~ all (root r) s. by apply: contraTN leNs; rewrite -ltnNge => /max_poly_roots->. have{PETr} [/= [p1 Dx] [q1 Dy]] := PETr (Subvs Kt) nz_rt. set z := t * y - x in Dx Dy; exists z; apply/eqP. rewrite eqEsubv !(sameP FadjoinP andP) subv_adjoin. have Kz_p1z (r1 : {poly subvs_of K}): (map_poly vsval r1).[z] \in <<K; z>>%VS. rewrite rpred_horner ?memv_adjoin ?(polyOverSv (subv_adjoin K z)) //. by apply/polyOver_subvs; exists r1. rewrite -{1}Dx -{1}Dy !{Dx Dy}Kz_p1z /=. rewrite (subv_trans (subv_adjoin K y)) ?subv_adjoin // rpredB ?memv_adjoin //. by rewrite subvP_adjoin // rpredM ?memv_adjoin ?subvP_adjoin. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
Primitive_Element_Theorem
adjoin_separable: separable_element <<K; y>> x -> separable_element K x. Proof. have /Derivation_separableP derKy := sepKy => /Derivation_separableP derKy_x. have [z defKz] := Primitive_Element_Theorem. suffices /adjoin_separableP: separable_element K z. by apply; rewrite -defKz memv_adjoin. apply/Derivation_separableP=> D; rewrite -defKz => derKxyD DK_0. suffices derKyD: Derivation <<K; y>>%VS D by rewrite derKy_x // derKy. by apply: DerivationS derKxyD; apply: subv_adjoin. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
adjoin_separable
strong_Primitive_Element_TheoremK x y : separable_element <<K; x>> y -> exists2 z : L, (<< <<K; y>>; x>> = <<K; z>>)%VS & separable_element K x -> separable_element K y. Proof. move=> sepKx_y; have [n /andP[pcharLn sepKyn]] := separable_exponent_pchar K y. have adjK_C z t: (<<<<K; z>>; t>> = <<<<K; t>>; z>>)%VS. by rewrite !agenv_add_id -!addvA (addvC <[_]>%VS). have [z defKz] := Primitive_Element_Theorem x sepKyn. exists z => [|/adjoin_separable->]; rewrite ?sepKx_y // -defKz. have [|n_gt1|-> //] := ltngtP n 1; first by case: (n) pcharLn. apply/eqP; rewrite !(adjK_C _ x) eqEsubv; apply/andP. split; apply/FadjoinP/andP; rewrite subv_adjoin ?rpredX ?memv_adjoin //=. by rewrite -pcharf_n_separable ?sepKx_y. Qed.
Lemma
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
strong_Primitive_Element_Theorem
separableU W : bool := all (separable_element U) (vbasis W).
Definition
field
[ "From HB Require Import structures", "From mathcomp Require Import ssreflect ssrbool ssrfun eqtype ssrnat seq div", "From mathcomp Require Import choice fintype tuple finfun bigop finset prime", "From mathcomp Require Import binomial ssralg poly polydiv fingroup perm", "From mathcomp Require Import morphism quotient gproduct finalg zmodp cyclic", "From mathcomp Require Import matrix mxalgebra mxpoly polyXY vector falgebra", "From mathcomp Require Import fieldext" ]
field/separable.v
separable