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chore(topology/basic): rename lemmas (#16598)
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`interior_eq_iff_open` -> `interior_eq_iff_is_open`, it's dual lemma `closure_eq_iff_is_closed` renamed in #4
`subset_interior_iff_open` -> `subset_interior_iff_is_open`
`subset_interior_iff_subset_of_open` -> `is_open.subset_interior_iff`, it's dual lemma `is_closed.closure_subset_iff` renamed in #3251
`closure_inter_open` -> `is_open.closure_inter`
`closure_inter_open'` -> `is_open.closure_inter'`
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negiizhao committed Sep 23, 2022
1 parent 79a2eb3 commit 3972305
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2 changes: 1 addition & 1 deletion src/analysis/calculus/extend_deriv.lean
Expand Up @@ -58,7 +58,7 @@ begin
{ rw closure_prod_eq at this,
intros y y_in,
apply this ⟨x, y⟩,
have : B ∩ closure s ⊆ closure (B ∩ s), from closure_inter_open is_open_ball,
have : B ∩ closure s ⊆ closure (B ∩ s), from is_open_ball.closure_inter,
exact ⟨this ⟨mem_ball_self δ_pos, hx⟩, this y_in⟩ },
have key : ∀ p : E × E, p ∈ (B ∩ s) ×ˢ (B ∩ s) → ∥f p.2 - f p.1 - (f' p.2 - f' p.1)∥
≤ ε * ∥p.2 - p.1∥,
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2 changes: 1 addition & 1 deletion src/analysis/convex/strict.lean
Expand Up @@ -144,7 +144,7 @@ variables [topological_space β] [linear_ordered_cancel_add_comm_monoid β] [ord
lemma strict_convex_Iic (r : β) : strict_convex 𝕜 (Iic r) :=
begin
rintro x (hx : x ≤ r) y (hy : y ≤ r) hxy a b ha hb hab,
refine (subset_interior_iff_subset_of_open is_open_Iio).2 Iio_subset_Iic_self _,
refine is_open_Iio.subset_interior_iff.2 Iio_subset_Iic_self _,
rw ←convex.combo_self hab r,
obtain rfl | hx := hx.eq_or_lt,
{ exact add_lt_add_left (smul_lt_smul_of_pos (hy.lt_of_ne hxy.symm) hb) _ },
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34 changes: 17 additions & 17 deletions src/topology/basic.lean
Expand Up @@ -248,13 +248,13 @@ subset_sUnion_of_mem ⟨h₂, h₁⟩
lemma is_open.interior_eq {s : set α} (h : is_open s) : interior s = s :=
subset.antisymm interior_subset (interior_maximal (subset.refl s) h)

lemma interior_eq_iff_open {s : set α} : interior s = s ↔ is_open s :=
lemma interior_eq_iff_is_open {s : set α} : interior s = s ↔ is_open s :=
⟨assume h, h ▸ is_open_interior, is_open.interior_eq⟩

lemma subset_interior_iff_open {s : set α} : s ⊆ interior s ↔ is_open s :=
by simp only [interior_eq_iff_open.symm, subset.antisymm_iff, interior_subset, true_and]
lemma subset_interior_iff_is_open {s : set α} : s ⊆ interior s ↔ is_open s :=
by simp only [interior_eq_iff_is_open.symm, subset.antisymm_iff, interior_subset, true_and]

lemma subset_interior_iff_subset_of_open {s t : set α} (h₁ : is_open s) :
lemma is_open.subset_interior_iff {s t : set α} (h₁ : is_open s) :
s ⊆ interior t ↔ s ⊆ t :=
⟨assume h, subset.trans h interior_subset, assume h₂, interior_maximal h₂ h₁⟩

Expand Down Expand Up @@ -305,7 +305,7 @@ have interior (s ∪ t) ⊆ s, from
have u \ s ⊆ t,
from assume x ⟨h₁, h₂⟩, or.resolve_left (hu₂ h₁) h₂,
have u \ s ⊆ interior t,
by rwa subset_interior_iff_subset_of_open (is_open.sdiff hu₁ h₁),
by rwa (is_open.sdiff hu₁ h₁).subset_interior_iff,
have u \ s ⊆ ∅,
by rwa h₂ at this,
this ⟨hx₁, hx₂⟩,
Expand All @@ -314,7 +314,7 @@ subset.antisymm
(interior_mono $ subset_union_left _ _)

lemma is_open_iff_forall_mem_open : is_open s ↔ ∀ x ∈ s, ∃ t ⊆ s, is_open t ∧ x ∈ t :=
by rw ← subset_interior_iff_open; simp only [subset_def, mem_interior]
by rw ← subset_interior_iff_is_open; simp only [subset_def, mem_interior]

lemma interior_Inter_subset (s : ι → set α) : interior (⋂ i, s i) ⊆ ⋂ i, interior (s i) :=
subset_Inter $ λ i, interior_mono $ Inter_subset _ _
Expand Down Expand Up @@ -364,9 +364,9 @@ lemma is_closed.closure_subset_iff {s t : set α} (h₁ : is_closed t) :
closure s ⊆ t ↔ s ⊆ t :=
⟨subset.trans subset_closure, assume h, closure_minimal h h₁⟩

lemma is_closed.mem_iff_closure_subset {α : Type*} [topological_space α] {U : set α}
(hU : is_closed U) {x : α} : x ∈ U ↔ closure ({x} : set α) ⊆ U :=
(hU.closure_subset_iff.trans set.singleton_subset_iff).symm
lemma is_closed.mem_iff_closure_subset {s : set α} (hs : is_closed s) {x : α} :
x ∈ s ↔ closure ({x} : set α) ⊆ s :=
(hs.closure_subset_iff.trans set.singleton_subset_iff).symm

@[mono] lemma closure_mono {s t : set α} (h : s ⊆ t) : closure s ⊆ closure t :=
closure_minimal (subset.trans h subset_closure) is_closed_closure
Expand Down Expand Up @@ -959,7 +959,7 @@ lemma subset_interior_iff_nhds {s V : set α} : s ⊆ interior V ↔ ∀ x ∈ s
show (∀ x, x ∈ s → x ∈ _) ↔ _, by simp_rw mem_interior_iff_mem_nhds

lemma is_open_iff_nhds {s : set α} : is_open s ↔ ∀a∈s, 𝓝 a ≤ 𝓟 s :=
calc is_open s ↔ s ⊆ interior s : subset_interior_iff_open.symm
calc is_open s ↔ s ⊆ interior s : subset_interior_iff_is_open.symm
... ↔ (∀a∈s, 𝓝 a ≤ 𝓟 s) : by rw [interior_eq_nhds]; refl

lemma is_open_iff_mem_nhds {s : set α} : is_open s ↔ ∀a∈s, s ∈ 𝓝 a :=
Expand All @@ -973,7 +973,7 @@ theorem is_open_iff_ultrafilter {s : set α} :
is_open s ↔ (∀ (x ∈ s) (l : ultrafilter α), ↑l ≤ 𝓝 x → s ∈ l) :=
by simp_rw [is_open_iff_mem_nhds, ← mem_iff_ultrafilter]

lemma is_open_singleton_iff_nhds_eq_pure {α : Type*} [topological_space α] (a : α) :
lemma is_open_singleton_iff_nhds_eq_pure (a : α) :
is_open ({a} : set α) ↔ 𝓝 a = pure a :=
begin
split,
Expand Down Expand Up @@ -1082,21 +1082,21 @@ calc is_closed s ↔ closure s ⊆ s : closure_subset_iff_is_closed.symm
lemma is_closed_iff_nhds {s : set α} : is_closed s ↔ ∀ x, (∀ U ∈ 𝓝 x, (U ∩ s).nonempty) → x ∈ s :=
by simp_rw [is_closed_iff_cluster_pt, cluster_pt, inf_principal_ne_bot_iff]

lemma closure_inter_open {s t : set α} (h : is_open s) : s ∩ closure t ⊆ closure (s ∩ t) :=
lemma is_open.closure_inter {s t : set α} (h : is_open s) : s ∩ closure t ⊆ closure (s ∩ t) :=
begin
rintro a ⟨hs, ht⟩,
have : s ∈ 𝓝 a := is_open.mem_nhds h hs,
rw mem_closure_iff_nhds_ne_bot at ht ⊢,
rwa [← inf_principal, ← inf_assoc, inf_eq_left.2 (le_principal_iff.2 this)],
end

lemma closure_inter_open' {s t : set α} (h : is_open t) : closure s ∩ t ⊆ closure (s ∩ t) :=
by simpa only [inter_comm] using closure_inter_open h
lemma is_open.closure_inter' {s t : set α} (h : is_open t) : closure s ∩ t ⊆ closure (s ∩ t) :=
by simpa only [inter_comm] using h.closure_inter

lemma dense.open_subset_closure_inter {s t : set α} (hs : dense s) (ht : is_open t) :
t ⊆ closure (t ∩ s) :=
calc t = t ∩ closure s : by rw [hs.closure_eq, inter_univ]
... ⊆ closure (t ∩ s) : closure_inter_open ht
... ⊆ closure (t ∩ s) : ht.closure_inter

lemma mem_closure_of_mem_closure_union {s₁ s₂ : set α} {x : α} (h : x ∈ closure (s₁ ∪ s₂))
(h₁ : s₁ᶜ ∈ 𝓝 x) : x ∈ closure s₂ :=
Expand All @@ -1112,7 +1112,7 @@ end
/-- The intersection of an open dense set with a dense set is a dense set. -/
lemma dense.inter_of_open_left {s t : set α} (hs : dense s) (ht : dense t) (hso : is_open s) :
dense (s ∩ t) :=
λ x, (closure_minimal (closure_inter_open hso) is_closed_closure) $
λ x, (closure_minimal hso.closure_inter is_closed_closure) $
by simp [hs.closure_eq, ht.closure_eq]

/-- The intersection of a dense set with an open dense set is a dense set. -/
Expand All @@ -1127,7 +1127,7 @@ let ⟨U, hsub, ho, hx⟩ := mem_nhds_iff.1 ht in

lemma closure_diff {s t : set α} : closure s \ closure t ⊆ closure (s \ t) :=
calc closure s \ closure t = (closure t)ᶜ ∩ closure s : by simp only [diff_eq, inter_comm]
... ⊆ closure ((closure t)ᶜ ∩ s) : closure_inter_open $ is_open_compl_iff.mpr $ is_closed_closure
... ⊆ closure ((closure t)ᶜ ∩ s) : (is_open_compl_iff.mpr $ is_closed_closure).closure_inter
... = closure (s \ closure t) : by simp only [diff_eq, inter_comm]
... ⊆ closure (s \ t) : closure_mono $ diff_subset_diff (subset.refl s) subset_closure

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2 changes: 1 addition & 1 deletion src/topology/locally_finite.lean
Expand Up @@ -78,7 +78,7 @@ begin
intro x,
rcases hf x with ⟨s, hsx, hsf⟩,
refine ⟨interior s, interior_mem_nhds.2 hsx, hsf.subset $ λ i hi, _⟩,
exact (hi.mono (closure_inter_open' is_open_interior)).of_closure.mono
exact (hi.mono is_open_interior.closure_inter').of_closure.mono
(inter_subset_inter_right _ interior_subset)
end

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2 changes: 1 addition & 1 deletion src/topology/maps.lean
Expand Up @@ -365,7 +365,7 @@ lemma is_open_map_iff_nhds_le [topological_space α] [topological_space β] {f :

lemma is_open_map_iff_interior [topological_space α] [topological_space β] {f : α → β} :
is_open_map f ↔ ∀ s, f '' (interior s) ⊆ interior (f '' s) :=
⟨is_open_map.image_interior_subset, λ hs u hu, subset_interior_iff_open.mp $
⟨is_open_map.image_interior_subset, λ hs u hu, subset_interior_iff_is_open.mp $
calc f '' u = f '' (interior u) : by rw hu.interior_eq
... ⊆ interior (f '' u) : hs u⟩

Expand Down
2 changes: 1 addition & 1 deletion src/topology/metric_space/hausdorff_distance.lean
Expand Up @@ -990,7 +990,7 @@ end

lemma thickening_subset_interior_cthickening (δ : ℝ) (E : set α) :
thickening δ E ⊆ interior (cthickening δ E) :=
(subset_interior_iff_open.mpr (is_open_thickening)).trans
(subset_interior_iff_is_open.mpr (is_open_thickening)).trans
(interior_mono (thickening_subset_cthickening δ E))

lemma closure_thickening_subset_cthickening (δ : ℝ) (E : set α) :
Expand Down
2 changes: 1 addition & 1 deletion src/topology/nhds_set.lean
Expand Up @@ -54,7 +54,7 @@ lemma has_basis_nhds_set (s : set α) : (𝓝ˢ s).has_basis (λ U, is_open U
⟨λ t, by simp [mem_nhds_set_iff_exists, and_assoc]⟩

lemma is_open.mem_nhds_set (hU : is_open s) : s ∈ 𝓝ˢ t ↔ t ⊆ s :=
by rw [← subset_interior_iff_mem_nhds_set, interior_eq_iff_open.mpr hU]
by rw [← subset_interior_iff_mem_nhds_set, interior_eq_iff_is_open.mpr hU]

lemma principal_le_nhds_set : 𝓟 s ≤ 𝓝ˢ s :=
λ s hs, (subset_interior_iff_mem_nhds_set.mpr hs).trans interior_subset
Expand Down
2 changes: 1 addition & 1 deletion src/topology/sets/opens.lean
Expand Up @@ -69,7 +69,7 @@ open order_dual (of_dual to_dual)

/-- The galois coinsertion between sets and opens. -/
def gi : galois_coinsertion subtype.val (@interior α _) :=
{ choice := λ s hs, ⟨s, interior_eq_iff_open.mp $ le_antisymm interior_subset hs⟩,
{ choice := λ s hs, ⟨s, interior_eq_iff_is_open.mp $ le_antisymm interior_subset hs⟩,
gc := gc,
u_l_le := λ _, interior_subset,
choice_eq := λ s hs, le_antisymm hs interior_subset }
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2 changes: 1 addition & 1 deletion src/topology/subset_properties.lean
Expand Up @@ -1390,7 +1390,7 @@ protected lemma is_clopen.is_closed (hs : is_clopen s) : is_closed s := hs.2

lemma is_clopen_iff_frontier_eq_empty {s : set α} : is_clopen s ↔ frontier s = ∅ :=
begin
rw [is_clopen, ← closure_eq_iff_is_closed, ← interior_eq_iff_open, frontier, diff_eq_empty],
rw [is_clopen, ← closure_eq_iff_is_closed, ← interior_eq_iff_is_open, frontier, diff_eq_empty],
refine ⟨λ h, (h.2.trans h.1.symm).subset, λ h, _⟩,
exact ⟨interior_subset.antisymm (subset_closure.trans h),
(h.trans interior_subset).antisymm subset_closure⟩
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2 changes: 1 addition & 1 deletion src/topology/uniform_space/basic.lean
Expand Up @@ -848,7 +848,7 @@ le_antisymm
let ⟨t, ht, hst, ht_comp⟩ := nhdset_of_mem_uniformity s hs in
have s ⊆ interior d, from
calc s ⊆ t : hst
... ⊆ interior d : (subset_interior_iff_subset_of_open ht).mpr $
... ⊆ interior d : ht.subset_interior_iff.mpr $
λ x (hx : x ∈ t), let ⟨x, y, h₁, h₂, h₃⟩ := ht_comp hx in hs_comp ⟨x, h₁, y, h₂, h₃⟩,
have interior d ∈ 𝓤 α, by filter_upwards [hs] using this,
by simp [this])
Expand Down

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