diff options
| author | Reynald Affeldt | 2020-04-06 03:04:22 +0900 |
|---|---|---|
| committer | Reynald Affeldt | 2020-04-15 21:07:29 +0900 |
| commit | 710a449fad7132a6ac89d19159fda44e48718b1d (patch) | |
| tree | 266097e8c886ffc62c62a459d2982ef798340025 /mathcomp/fingroup/action.v | |
| parent | 71f2fc1e08817af19edcedf0e2980a499951fba3 (diff) | |
addressing comments about PR#221 of mathcomp
Diffstat (limited to 'mathcomp/fingroup/action.v')
| -rw-r--r-- | mathcomp/fingroup/action.v | 47 |
1 files changed, 22 insertions, 25 deletions
diff --git a/mathcomp/fingroup/action.v b/mathcomp/fingroup/action.v index 651dd6d..9631d28 100644 --- a/mathcomp/fingroup/action.v +++ b/mathcomp/fingroup/action.v @@ -1607,7 +1607,7 @@ Qed. Canonical perm_action := Action aperm_is_action. -Lemma pcycleE a : pcycle a = orbit perm_action <[a]>%g. +Lemma porbitE a : porbit a = orbit perm_action <[a]>%g. Proof. by []. Qed. Lemma perm_act1P a : reflect (forall x, aperm x a = x) (a == 1). @@ -1643,11 +1643,11 @@ move=> sAD x; rewrite morphimEsub // /orbit -imset_comp. by apply: eq_imset => a //=; rewrite actpermK. Qed. -Lemma pcycle_actperm (a : aT) : - a \in D -> pcycle (actperm to a) =1 orbit to <[a]>. +Lemma porbit_actperm (a : aT) : + a \in D -> porbit (actperm to a) =1 orbit to <[a]>. Proof. move=> Da x. -by rewrite pcycleE -orbit_morphim_actperm ?cycle_subG ?morphim_cycle. +by rewrite porbitE -orbit_morphim_actperm ?cycle_subG ?morphim_cycle. Qed. End ActpermOrbits. @@ -1680,26 +1680,8 @@ Proof. by rewrite ker_actperm astab_actby setIT (setIidPr (astab_sub _ _)). Qed. Lemma im_restr_perm p : restr_perm p @: S = S. Proof. exact: im_perm_on (restr_perm_on p). Qed. -Definition perm_ong : {set {perm T}} := [set s | perm_on S s]. -Lemma group_set_perm_ong : group_set perm_ong. -Proof using. -apply/group_setP; split => [| s t]; rewrite !inE; - [exact: perm_on1 | exact: perm_onM]. -Qed. -Canonical perm_ong_group : {group {perm T}} := Group group_set_perm_ong. -Lemma card_perm_ong : #|perm_ong| = #|S|`!. -Proof using. by rewrite cardsE /= card_perm. Qed. - -Lemma perm_ongE : perm_ong = 'C(~:S | 'P). -Proof using. -apply/setP => s; rewrite inE; apply/idP/astabP => [Hperm x | Hstab]. -- by rewrite inE /= apermE => /out_perm; apply. -- apply/subsetP => x; rewrite unfold_in; apply contraR => H. - by move/(_ x): Hstab; rewrite inE /= apermE => ->. -Qed. - Lemma restr_perm_commute s : commute (restr_perm s) s. -Proof using. +Proof. case: (boolP (s \in 'N(S | 'P))) => [HC | /triv_restr_perm ->]; last exact: (commute_sym (commute1 _)). apply/permP => x; case: (boolP (x \in S)) => Hx; rewrite !permM. @@ -1711,6 +1693,19 @@ Qed. End RestrictPerm. +Section Symmetry. + +Variables (T : finType) (S : {set T}). + +Lemma SymE : Sym S = 'C(~: S | 'P). +Proof. +apply/setP => s; rewrite inE; apply/idP/astabP => [Hperm x | Hstab]. +- by rewrite inE /= apermE => /out_perm; apply. +- apply/subsetP => x; rewrite unfold_in; apply contraR => H. + by move/(_ x): Hstab; rewrite inE /= apermE => ->. +Qed. + +End Symmetry. Section AutIn. @@ -2403,7 +2398,7 @@ exact: (morph_afix (gact_stable to1) (injmP injh)). Qed. Lemma morph_gact_irr A M : - A \subset D1 -> M \subset R1 -> + A \subset D1 -> M \subset R1 -> acts_irreducibly (f @* A) (h @* M) to2 = acts_irreducibly A M to1. Proof. move=> sAD1 sMR1. @@ -2737,4 +2732,6 @@ Arguments aut_groupAction {gT} G%g. Notation "[ 'Aut' G ]" := (aut_action G) : action_scope. Notation "[ 'Aut' G ]" := (aut_groupAction G) : groupAction_scope. - +Notation pcycleE := (deprecate pcycleE porbitE _) (only parsing). +Notation pcycle_actperm := (deprecate pcycle_actperm porbit_actperm _) + (only parsing). |
