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[Merged by Bors] - chore: rename some lemmas involving "of_closed" #8492

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2 changes: 1 addition & 1 deletion Mathlib/MeasureTheory/Function/ContinuousMapDense.lean
Original file line number Diff line number Diff line change
Expand Up @@ -93,7 +93,7 @@ theorem exists_continuous_snorm_sub_le_of_closed [μ.OuterRegular] (hp : p ≠
have hsv : s ⊆ v := subset_inter hsu sV
have hμv : μ v < ∞ := (measure_mono (inter_subset_right _ _)).trans_lt h'V
obtain ⟨g, hgv, hgs, hg_range⟩ :=
exists_continuous_zero_one_of_closed (u_open.inter V_open).isClosed_compl s_closed
exists_continuous_zero_one_of_isClosed (u_open.inter V_open).isClosed_compl s_closed
(disjoint_compl_left_iff.2 hsv)
-- Multiply this by `c` to get a continuous approximation to the function `f`; the key point is
-- that this is pointwise bounded by the indicator of the set `v \ s`, which has small measure.
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2 changes: 1 addition & 1 deletion Mathlib/Topology/Category/CompHaus/Basic.lean
Original file line number Diff line number Diff line change
Expand Up @@ -340,7 +340,7 @@ theorem epi_iff_surjective {X Y : CompHaus.{u}} (f : X ⟶ Y) : Epi f ↔ Functi
rw [Set.disjoint_singleton_right]
rintro ⟨y', hy'⟩
exact hy y' hy'
obtain ⟨φ, hφ0, hφ1, hφ01⟩ := exists_continuous_zero_one_of_closed hC hD hCD
obtain ⟨φ, hφ0, hφ1, hφ01⟩ := exists_continuous_zero_one_of_isClosed hC hD hCD
haveI : CompactSpace (ULift.{u} <| Set.Icc (0 : ℝ) 1) := Homeomorph.ulift.symm.compactSpace
haveI : T2Space (ULift.{u} <| Set.Icc (0 : ℝ) 1) := Homeomorph.ulift.symm.t2Space
let Z := of (ULift.{u} <| Set.Icc (0 : ℝ) 1)
Expand Down
2 changes: 1 addition & 1 deletion Mathlib/Topology/CompletelyRegular.lean
Original file line number Diff line number Diff line change
Expand Up @@ -75,7 +75,7 @@ instance NormalSpace.completelyRegularSpace [NormalSpace X] : CompletelyRegularS
intro x K hK hx
have cx : IsClosed {x} := by apply T1Space.t1
have d : Disjoint {x} K := by rwa [Set.disjoint_iff, subset_empty_iff, singleton_inter_eq_empty]
let ⟨⟨f, cf⟩, hfx, hfK, hficc⟩ := exists_continuous_zero_one_of_closed cx hK d
let ⟨⟨f, cf⟩, hfx, hfK, hficc⟩ := exists_continuous_zero_one_of_isClosed cx hK d
let g : X → I := fun x => ⟨f x, hficc x⟩
have cg : Continuous g := cf.subtype_mk hficc
have hgx : g x = 0 := Subtype.ext (hfx (mem_singleton_iff.mpr (Eq.refl x)))
Expand Down
10 changes: 5 additions & 5 deletions Mathlib/Topology/Connected/Basic.lean
Original file line number Diff line number Diff line change
Expand Up @@ -383,7 +383,7 @@ theorem IsPreconnected.preimage_of_open_map [TopologicalSpace β] {s : Set β} (
· exact ⟨a, has, hau, hinj.mem_set_image.1 hav⟩
#align is_preconnected.preimage_of_open_map IsPreconnected.preimage_of_open_map

theorem IsPreconnected.preimage_of_closed_map [TopologicalSpace β] {s : Set β}
theorem IsPreconnected.preimage_of_isClosedMap [TopologicalSpace β] {s : Set β}
(hs : IsPreconnected s) {f : α → β} (hinj : Function.Injective f) (hf : IsClosedMap f)
(hsf : s ⊆ range f) : IsPreconnected (f ⁻¹' s) :=
isPreconnected_closed_iff.2 fun u v hu hv hsuv hsu hsv => by
Expand All @@ -394,19 +394,19 @@ theorem IsPreconnected.preimage_of_closed_map [TopologicalSpace β] {s : Set β}
· simpa only [image_preimage_inter] using hsu.image f
· simpa only [image_preimage_inter] using hsv.image f
· exact ⟨a, has, hau, hinj.mem_set_image.1 hav⟩
#align is_preconnected.preimage_of_closed_map IsPreconnected.preimage_of_closed_map
#align is_preconnected.preimage_of_closed_map IsPreconnected.preimage_of_isClosedMap

theorem IsConnected.preimage_of_openMap [TopologicalSpace β] {s : Set β} (hs : IsConnected s)
{f : α → β} (hinj : Function.Injective f) (hf : IsOpenMap f) (hsf : s ⊆ range f) :
IsConnected (f ⁻¹' s) :=
⟨hs.nonempty.preimage' hsf, hs.isPreconnected.preimage_of_open_map hinj hf hsf⟩
#align is_connected.preimage_of_open_map IsConnected.preimage_of_openMap

theorem IsConnected.preimage_of_closedMap [TopologicalSpace β] {s : Set β} (hs : IsConnected s)
theorem IsConnected.preimage_of_isClosedMap [TopologicalSpace β] {s : Set β} (hs : IsConnected s)
{f : α → β} (hinj : Function.Injective f) (hf : IsClosedMap f) (hsf : s ⊆ range f) :
IsConnected (f ⁻¹' s) :=
⟨hs.nonempty.preimage' hsf, hs.isPreconnected.preimage_of_closed_map hinj hf hsf⟩
#align is_connected.preimage_of_closed_map IsConnected.preimage_of_closedMap
⟨hs.nonempty.preimage' hsf, hs.isPreconnected.preimage_of_isClosedMap hinj hf hsf⟩
#align is_connected.preimage_of_closed_map IsConnected.preimage_of_isClosedMap

theorem IsPreconnected.subset_or_subset (hu : IsOpen u) (hv : IsOpen v) (huv : Disjoint u v)
(hsuv : s ⊆ u ∪ v) (hs : IsPreconnected s) : s ⊆ u ∨ s ⊆ v := by
Expand Down
4 changes: 2 additions & 2 deletions Mathlib/Topology/ContinuousFunction/Ideals.lean
Original file line number Diff line number Diff line change
Expand Up @@ -324,7 +324,7 @@ theorem setOfIdeal_ofSet_eq_interior (s : Set X) : setOfIdeal (idealOfSet 𝕜 s
/- Apply Urysohn's lemma to get `g : C(X, ℝ)` which is zero on `sᶜ` and `g x ≠ 0`, then compose
with the natural embedding `ℝ ↪ 𝕜` to produce the desired `f`. -/
obtain ⟨g, hgs, hgx : Set.EqOn g 1 {x}, -⟩ :=
exists_continuous_zero_one_of_closed isClosed_closure isClosed_singleton
exists_continuous_zero_one_of_isClosed isClosed_closure isClosed_singleton
(Set.disjoint_singleton_right.mpr hx)
exact
⟨⟨fun x => g x, continuous_ofReal.comp (map_continuous g)⟩, by
Expand Down Expand Up @@ -435,7 +435,7 @@ variable [CompactSpace X] [T2Space X] [IsROrC 𝕜]
theorem continuousMapEval_bijective : Bijective (continuousMapEval X 𝕜) := by
refine' ⟨fun x y hxy => _, fun φ => _⟩
· contrapose! hxy
rcases exists_continuous_zero_one_of_closed (isClosed_singleton : _root_.IsClosed {x})
rcases exists_continuous_zero_one_of_isClosed (isClosed_singleton : _root_.IsClosed {x})
(isClosed_singleton : _root_.IsClosed {y}) (Set.disjoint_singleton.mpr hxy) with
⟨f, fx, fy, -⟩
rw [FunLike.ne_iff]
Expand Down
2 changes: 1 addition & 1 deletion Mathlib/Topology/Metrizable/Urysohn.lean
Original file line number Diff line number Diff line change
Expand Up @@ -62,7 +62,7 @@ theorem exists_inducing_l_infty : ∃ f : X → ℕ →ᵇ ℝ, Inducing f := by
have : ∀ UV : s, ∃ f : C(X, ℝ),
EqOn f 0 UV.1.1 ∧ EqOn f (fun _ => ε UV) UV.1.2ᶜ ∧ ∀ x, f x ∈ Icc 0 (ε UV) := by
intro UV
rcases exists_continuous_zero_one_of_closed isClosed_closure
rcases exists_continuous_zero_one_of_isClosed isClosed_closure
(hB.isOpen UV.2.1.2).isClosed_compl (hd UV) with
⟨f, hf₀, hf₁, hf01⟩
exact ⟨ε UV • f, fun x hx => by simp [hf₀ (subset_closure hx)], fun x hx => by simp [hf₁ hx],
Expand Down
2 changes: 1 addition & 1 deletion Mathlib/Topology/PartitionOfUnity.lean
Original file line number Diff line number Diff line change
Expand Up @@ -321,7 +321,7 @@ theorem exists_isSubordinate_of_locallyFinite [NormalSpace X] (hs : IsClosed s)
let ⟨f, _, hfU⟩ :=
exists_isSubordinate_of_locallyFinite_of_prop (fun _ => True)
(fun _ _ hs ht hd =>
(exists_continuous_zero_one_of_closed hs ht hd).imp fun _ hf => ⟨trivial, hf⟩)
(exists_continuous_zero_one_of_isClosed hs ht hd).imp fun _ hf => ⟨trivial, hf⟩)
hs U ho hf hU
⟨f, hfU⟩
#align bump_covering.exists_is_subordinate_of_locally_finite BumpCovering.exists_isSubordinate_of_locallyFinite
Expand Down
4 changes: 2 additions & 2 deletions Mathlib/Topology/UrysohnsBounded.lean
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ import Mathlib.Topology.ContinuousFunction.Bounded
/-!
# Urysohn's lemma for bounded continuous functions

In this file we reformulate Urysohn's lemma `exists_continuous_zero_one_of_closed` in terms of
In this file we reformulate Urysohn's lemma `exists_continuous_zero_one_of_isClosed` in terms of
bounded continuous functions `X →ᵇ ℝ`. These lemmas live in a separate file because
`Topology.ContinuousFunction.Bounded` imports too many other files.

Expand All @@ -35,7 +35,7 @@ then there exists a continuous function `f : X → ℝ` such that
theorem exists_bounded_zero_one_of_closed {X : Type*} [TopologicalSpace X] [NormalSpace X]
{s t : Set X} (hs : IsClosed s) (ht : IsClosed t) (hd : Disjoint s t) :
∃ f : X →ᵇ ℝ, EqOn f 0 s ∧ EqOn f 1 t ∧ ∀ x, f x ∈ Icc (0 : ℝ) 1 :=
let ⟨f, hfs, hft, hf⟩ := exists_continuous_zero_one_of_closed hs ht hd
let ⟨f, hfs, hft, hf⟩ := exists_continuous_zero_one_of_isClosed hs ht hd
⟨⟨f, 1, fun _ _ => Real.dist_le_of_mem_Icc_01 (hf _) (hf _)⟩, hfs, hft, hf⟩
#align exists_bounded_zero_one_of_closed exists_bounded_zero_one_of_closed

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6 changes: 3 additions & 3 deletions Mathlib/Topology/UrysohnsLemma.lean
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@ import Mathlib.Topology.ContinuousFunction.Basic
/-!
# Urysohn's lemma

In this file we prove Urysohn's lemma `exists_continuous_zero_one_of_closed`: for any two disjoint
In this file we prove Urysohn's lemma `exists_continuous_zero_one_of_isClosed`: for any two disjoint
closed sets `s` and `t` in a normal topological space `X` there exists a continuous function
`f : X → ℝ` such that

Expand Down Expand Up @@ -320,7 +320,7 @@ then there exists a continuous function `f : X → ℝ` such that
* `f` equals one on `t`;
* `0 ≤ f x ≤ 1` for all `x`.
-/
theorem exists_continuous_zero_one_of_closed [NormalSpace X]
theorem exists_continuous_zero_one_of_isClosed [NormalSpace X]
{s t : Set X} (hs : IsClosed s) (ht : IsClosed t)
(hd : Disjoint s t) : ∃ f : C(X, ℝ), EqOn f 0 s ∧ EqOn f 1 t ∧ ∀ x, f x ∈ Icc (0 : ℝ) 1 := by
-- The actual proof is in the code above. Here we just repack it into the expected format.
Expand All @@ -338,7 +338,7 @@ theorem exists_continuous_zero_one_of_closed [NormalSpace X]
exact ⟨v, v_open, cv, hv, trivial⟩ }
exact ⟨⟨c.lim, c.continuous_lim⟩, c.lim_of_mem_C, fun x hx => c.lim_of_nmem_U _ fun h => h hx,
c.lim_mem_Icc⟩
#align exists_continuous_zero_one_of_closed exists_continuous_zero_one_of_closed
#align exists_continuous_zero_one_of_closed exists_continuous_zero_one_of_isClosed

/-- Urysohn's lemma: if `s` and `t` are two disjoint sets in a regular locally compact topological
space `X`, with `s` compact and `t` closed, then there exists a continuous
Expand Down
2 changes: 1 addition & 1 deletion docs/overview.yaml
Original file line number Diff line number Diff line change
Expand Up @@ -217,7 +217,7 @@ Topology:
Stone-Cech compactification: 'StoneCech'
topological fiber bundle: 'FiberBundle'
topological vector bundle: 'VectorBundle'
Urysohn's lemma: 'exists_continuous_zero_one_of_closed'
Urysohn's lemma: 'exists_continuous_zero_one_of_isClosed'
Stone-Weierstrass theorem: 'ContinuousMap.subalgebra_topologicalClosure_eq_top_of_separatesPoints'
Uniform notions:
uniform space: 'UniformSpace'
Expand Down