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small lint
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zstone1 committed Aug 5, 2023
1 parent 8d47d78 commit 7d2f2b4
Showing 1 changed file with 19 additions and 16 deletions.
35 changes: 19 additions & 16 deletions theories/normedtype.v
Original file line number Diff line number Diff line change
Expand Up @@ -4188,6 +4188,8 @@ exists (Uniform.class T'), ([set xy | ball (f xy.1) 1 (f xy.2)]); split.
Qed.

Section normalP.
Locate Real.type.
Print realType.
Context {T : topologicalType} {R : realType}.
Let normal_spaceP : [<->
(* 0 *) normal_space T;
Expand All @@ -4197,12 +4199,12 @@ Let normal_spaceP : [<->
exists U V, [/\ open U, open V, A `<=` U, B `<=` V & U `&` V = set0]
].
Proof.
tfae; first by move=> *; exact: normal_uniform_separator.
tfae; first by move=> ?; exact: normal_uniform_separator.
- move=> + A B clA clB AB0 => /(_ _ _ clA clB AB0) /(@uniform_separatorP _ R).
case=> f [cf f01 /imsub1P/subset_trans fa0 /imsub1P/subset_trans fb1].
case=> f [cf f01 /imsub1P/subset_trans fa0 /imsub1P/subset_trans fb1].
exists (f@^-1` `]-1, 1/2[), (f@^-1` `]1/2, 2[); split.
+ by apply: open_comp; [|exact: interval_open] => + _ .
+ by apply: open_comp; [|exact: interval_open] => + _ .
+ by apply: open_comp; [|exact: interval_open].
+ by apply: open_comp; [|exact: interval_open].
+ by apply: fa0; rewrite set_itvoo => x /= ->; apply/andP; split.
+ apply: fb1; rewrite set_itvoo => x /= ->.
by rewrite ltr_pdivr_mulr // mul1r Bool.andb_diag ltr_addl.
Expand All @@ -4212,15 +4214,15 @@ move=> + A clA B /set_nbhsP [C [oC AC CB]].
have AC0 : A `&` ~` C = set0 by apply/disjoints_subset; rewrite setCK.
case/(_ _ _ clA (open_closedC oC) AC0)=> U [V] [oU oV AU nCV UV0].
exists (~` (closure V)).
apply/set_nbhsP; exists (U); split => //.
apply/subsetCr; have := (open_closedC oU); rewrite closure_id => ->.
apply/set_nbhsP; exists (U); split => //.
apply/subsetCr; have := (open_closedC oU); rewrite closure_id => ->.
by apply: closure_subset; apply/disjoints_subset; rewrite setIC.
apply: (subset_trans _ CB); apply/subsetCP; apply: (subset_trans nCV).
apply/subsetCr; have := (open_closedC oV); rewrite closure_id => ->.
apply/subsetCr; have := (open_closedC oV); rewrite closure_id => ->.
by apply: closure_subset; apply/subsetC; exact: subset_closure.
Qed.

Lemma normal_openP : normal_space T <->
Lemma normal_openP : normal_space T <->
forall (A B : set T), closed A -> closed B -> A `&` B = set0 ->
exists U V, [/\ open U, open V, A `<=` U, B `<=` V & U `&` V = set0].
Proof. exact: (normal_spaceP 0%N 2%N). Qed.
Expand All @@ -4232,21 +4234,22 @@ Proof. exact: (normal_spaceP 0%N 1%N). Qed.
End normalP.

Section pseudometric_normal.

Lemma uniform_regular {X : uniformType} : @regular_space X.
Proof.
move=> x A; rewrite /= -nbhs_entourageE; case => E entE.
move/(subset_trans (ent_closure entE)) => ?.
by exists [set y | (split_ent E) (x, y)]; first by exists (split_ent E).
Qed.

Lemma regular_openP {T : topologicalType} (x : T) :
{for x, @regular_space T} <-> (forall A, closed A -> ~ A x -> exists (U V : set T),
[/\ open U, open V, U x, A `<=` V & U `&` V = set0]).
Lemma regular_openP {T : topologicalType} (x : T) :
{for x, @regular_space T} <-> (forall A, closed A -> ~ A x ->
exists (U V : set T), [/\ open U, open V, U x, A `<=` V & U `&` V = set0]).
Proof.
split.
move=> + A clA nAx => /(_ (~` A)) [].
by apply: open_nbhs_nbhs; split => //; apply: closed_openC.
move=> U Ux /subsetC; rewrite setCK => AclU; exists (interior U).
move=> U Ux /subsetC; rewrite setCK => AclU; exists (interior U).
exists (~` (closure U)); split => //; first exact: open_interior.
by apply: closed_openC; exact: closed_closure.
apply/disjoints_subset; rewrite setCK; apply: (@subset_trans _ U).
Expand All @@ -4257,11 +4260,11 @@ move=> + A Ax => /(_ (~` (interior A))) []; [|exact|].
move=> U [V] [oU oV Ux /subsetC cAV /disjoints_subset UV]; exists U.
by apply: open_nbhs_nbhs; split.
apply: subset_trans; first exact: (closure_subset UV).
move/open_closedC/closure_id:oV => <-.
move/open_closedC/closure_id: oV => <-.
apply: (subset_trans cAV); rewrite setCK; exact: interior_subset.
Qed.

Lemma pseudometric_normal {R : realType} {X : pseudoMetricType R} :
Lemma pseudometric_normal {R : realType} {X : pseudoMetricType R} :
normal_space X.
Proof.
apply/(@normal_openP _ R) => A B clA clB AB0.
Expand Down Expand Up @@ -4290,8 +4293,8 @@ case: (pselect ((epsA x)%:num/2 <= (epsB y)%:num/2)).
move/ball_sym:Axe =>/[swap] /le_ball /[apply] /(ball_triangle Bye).
rewrite -splitr => byx; have := projT2 (cid (eps' _ clA y)) nAy.
by rewrite -subset0; apply; split; first exact: byx.
move/negP; rewrite leNgt negbK => /ltW.
move/ball_sym:Bye =>/[swap] /le_ball /[apply] /(ball_triangle Axe).
move/negP; rewrite leNgt negbK => /ltW.
move/ball_sym:Bye =>/[swap] /le_ball /[apply] /(ball_triangle Axe).
rewrite -splitr => byx; have := projT2 (cid (eps' _ clB x)) nBx.
by rewrite -subset0; apply; split; first exact: byx.
Qed.
Expand Down

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