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coe_prod (K : PositiveCompacts α) (L : PositiveCompacts β) : (K ×ˢ L : PositiveCompacts (α × β)) = (K : Set α) ×ˢ (L : Set β)
rfl
theorem
TopologicalSpace.PositiveCompacts.coe_prod
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
CompactOpens (α : Type*) [TopologicalSpace α] extends Compacts α where isOpen' : IsOpen carrier
structure
TopologicalSpace.CompactOpens
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "IsOpen", "TopologicalSpace" ]
The type of compact open sets of a topological space. This is useful in non-Hausdorff contexts, in particular spectral spaces.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Simps.coe (s : CompactOpens α) : Set α
s initialize_simps_projections CompactOpens (carrier → coe, as_prefix coe, as_prefix toCompacts)
def
TopologicalSpace.CompactOpens.Simps.coe
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
See Note [custom simps projection].
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isCompact (s : CompactOpens α) : IsCompact (s : Set α)
s.isCompact'
theorem
TopologicalSpace.CompactOpens.isCompact
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "IsCompact", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isOpen (s : CompactOpens α) : IsOpen (s : Set α)
s.isOpen'
theorem
TopologicalSpace.CompactOpens.isOpen
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "IsOpen", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toOpens (s : CompactOpens α) : Opens α
⟨s, s.isOpen⟩
def
TopologicalSpace.CompactOpens.toOpens
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[]
Reinterpret a compact open as an open.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toClopens [T2Space α] (s : CompactOpens α) : Clopens α
⟨s, s.isCompact.isClosed, s.isOpen⟩
def
TopologicalSpace.CompactOpens.toClopens
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "T2Space" ]
Reinterpret a compact open as a clopen.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ext {s t : CompactOpens α} (h : (s : Set α) = t) : s = t
SetLike.ext' h
theorem
TopologicalSpace.CompactOpens.ext
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set", "SetLike.ext'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_sup (s t : CompactOpens α) : ↑(s ⊔ t) = (s ∪ t : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_sup
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_bot : ↑(⊥ : CompactOpens α) = (∅ : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_bot
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_finsetSup {ι : Type*} {f : ι → CompactOpens α} {s : Finset ι} : (↑(s.sup f) : Set α) = ⋃ i ∈ s, f i
by classical induction s using Finset.induction_on <;> simp [*]
lemma
TopologicalSpace.CompactOpens.coe_finsetSup
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Finset", "Finset.induction_on", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instInf : Min (CompactOpens α)
where min U V := ⟨⟨U ∩ V, QuasiSeparatedSpace.inter_isCompact U.1.1 V.1.1 U.2 U.1.2 V.2 V.1.2⟩, U.2.inter V.2⟩
instance
TopologicalSpace.CompactOpens.instInf
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_inf (s t : CompactOpens α) : ↑(s ⊓ t) = (s ∩ t : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_inf
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instSemilatticeInf : SemilatticeInf (CompactOpens α)
fast_instance% SetLike.coe_injective.semilatticeInf _ .rfl .rfl coe_inf
instance
TopologicalSpace.CompactOpens.instSemilatticeInf
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "SemilatticeInf" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instSDiff : SDiff (CompactOpens α)
where sdiff s t := ⟨⟨s \ t, s.isCompact.diff t.isOpen⟩, s.isOpen.sdiff t.isCompact.isClosed⟩
instance
TopologicalSpace.CompactOpens.instSDiff
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_sdiff (s t : CompactOpens α) : ↑(s \ t) = (s \ t : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_sdiff
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instGeneralizedBooleanAlgebra : GeneralizedBooleanAlgebra (CompactOpens α)
fast_instance% SetLike.coe_injective.generalizedBooleanAlgebra _ .rfl .rfl coe_sup coe_inf coe_bot coe_sdiff
instance
TopologicalSpace.CompactOpens.instGeneralizedBooleanAlgebra
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "GeneralizedBooleanAlgebra" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instTop : Top (CompactOpens α)
where top := ⟨⊤, isOpen_univ⟩
instance
TopologicalSpace.CompactOpens.instTop
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Top" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_top : ↑(⊤ : CompactOpens α) = (univ : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_top
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instBoundedOrder : BoundedOrder (CompactOpens α)
fast_instance% BoundedOrder.lift ((↑) : _ → Set α) (fun _ _ => id) coe_top coe_bot
instance
TopologicalSpace.CompactOpens.instBoundedOrder
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "BoundedOrder", "BoundedOrder.lift", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instCompl : Compl (CompactOpens α)
where compl s := ⟨⟨sᶜ, s.isOpen.isClosed_compl.isCompact⟩, s.isCompact.isClosed.isOpen_compl⟩
instance
TopologicalSpace.CompactOpens.instCompl
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Compl" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instHImp : HImp (CompactOpens α)
where himp s t := ⟨⟨s ⇨ t, IsClosed.isCompact (by simpa [himp_eq] using t.isCompact.isClosed.union s.isOpen.isClosed_compl)⟩, by simpa [himp_eq] using t.isOpen.union s.isCompact.isClosed.isOpen_compl⟩
instance
TopologicalSpace.CompactOpens.instHImp
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "HImp", "IsClosed.isCompact", "himp_eq" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_compl (s : CompactOpens α) : ↑sᶜ = (sᶜ : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_compl
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_himp (s t : CompactOpens α) : ↑(s ⇨ t) = (s ⇨ t : Set α)
rfl
lemma
TopologicalSpace.CompactOpens.coe_himp
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instBooleanAlgebra : BooleanAlgebra (CompactOpens α)
fast_instance% SetLike.coe_injective.booleanAlgebra _ .rfl .rfl coe_sup coe_inf coe_top coe_bot coe_compl coe_sdiff coe_himp
instance
TopologicalSpace.CompactOpens.instBooleanAlgebra
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "BooleanAlgebra" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
map (f : α → β) (hf : Continuous f) (hf' : IsOpenMap f) (s : CompactOpens α) : CompactOpens β
⟨s.toCompacts.map f hf, hf' _ s.isOpen⟩
def
TopologicalSpace.CompactOpens.map
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Continuous", "IsOpenMap" ]
The image of a compact open under a continuous open map.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_map {f : α → β} (hf : Continuous f) (hf' : IsOpenMap f) (s : CompactOpens α) : (s.map f hf hf' : Set β) = f '' s
rfl
theorem
TopologicalSpace.CompactOpens.coe_map
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Continuous", "IsOpenMap", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
map_id (K : CompactOpens α) : K.map id continuous_id IsOpenMap.id = K
CompactOpens.ext <| Set.image_id _
theorem
TopologicalSpace.CompactOpens.map_id
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set.image_id", "continuous_id" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
map_comp (f : β → γ) (g : α → β) (hf : Continuous f) (hg : Continuous g) (hf' : IsOpenMap f) (hg' : IsOpenMap g) (K : CompactOpens α) : K.map (f ∘ g) (hf.comp hg) (hf'.comp hg') = (K.map g hg hg').map f hf hf'
CompactOpens.ext <| Set.image_comp _ _ _
theorem
TopologicalSpace.CompactOpens.map_comp
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Continuous", "IsOpenMap", "Set.image_comp" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_prod (K : CompactOpens α) (L : CompactOpens β) : (K ×ˢ L : CompactOpens (α × β)) = (K : Set α) ×ˢ (L : Set β)
rfl
theorem
TopologicalSpace.CompactOpens.coe_prod
Topology.Sets
Mathlib/Topology/Sets/Compacts.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsOpenCover {ι X : Type*} [TopologicalSpace X] (u : ι → Opens X) : Prop
iSup u = ⊤
def
TopologicalSpace.IsOpenCover
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "TopologicalSpace", "iSup" ]
An indexed family of open sets whose union is `X`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk (h : iSup u = ⊤) : IsOpenCover u
h
lemma
TopologicalSpace.IsOpenCover.mk
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
of_sets {v : ι → Set X} (h_open : ∀ i, IsOpen (v i)) (h_iUnion : ⋃ i, v i = univ) : IsOpenCover (fun i ↦ ⟨v i, h_open i⟩)
by simp [IsOpenCover, h_iUnion]
lemma
TopologicalSpace.IsOpenCover.of_sets
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "IsOpen", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iSup_eq_top (hu : IsOpenCover u) : ⨆ i, u i = ⊤
hu
lemma
TopologicalSpace.IsOpenCover.iSup_eq_top
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "iSup_eq_top" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iSup_set_eq_univ (hu : IsOpenCover u) : ⋃ i, (u i : Set X) = univ
by simpa [← SetLike.coe_set_eq] using hu.iSup_eq_top
lemma
TopologicalSpace.IsOpenCover.iSup_set_eq_univ
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Set", "SetLike.coe_set_eq" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comap (hv : IsOpenCover v) (f : C(X, Y)) : IsOpenCover fun k ↦ (v k).comap f
by simp [IsOpenCover, ← preimage_iUnion, hv.iSup_set_eq_univ]
lemma
TopologicalSpace.IsOpenCover.comap
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "comap" ]
Pullback of a covering of `Y` by a continuous map `X → Y`, giving a covering of `X` with the same index type.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_mem (hu : IsOpenCover u) (a : X) : ∃ i, a ∈ u i
by simpa [← hu.iSup_set_eq_univ] using mem_univ a
lemma
TopologicalSpace.IsOpenCover.exists_mem
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_mem_nhds (hu : IsOpenCover u) (a : X) : ∃ i, (u i : Set X) ∈ 𝓝 a
match hu.exists_mem a with | ⟨i, hi⟩ => ⟨i, (u i).isOpen.mem_nhds hi⟩
lemma
TopologicalSpace.IsOpenCover.exists_mem_nhds
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iUnion_inter (hu : IsOpenCover u) (s : Set X) : ⋃ i, s ∩ u i = s
by simp [← inter_iUnion, hu.iSup_set_eq_univ]
lemma
TopologicalSpace.IsOpenCover.iUnion_inter
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isTopologicalBasis (hu : IsOpenCover u) {B : ∀ i, Set (Set (u i))} (hB : ∀ i, IsTopologicalBasis (B i)) : IsTopologicalBasis (⋃ i, (Subtype.val '' ·) '' B i)
isTopologicalBasis_of_cover (fun i ↦ (u i).2) hu.iSup_set_eq_univ hB
lemma
TopologicalSpace.IsOpenCover.isTopologicalBasis
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Opens.IsBasis.isOpenCover {S : Set (Opens X)} (hS : Opens.IsBasis S) : IsOpenCover (fun U : S ↦ (U : Opens X))
top_le_iff.mp (subset_trans hS.2.superset (by simp))
lemma
TopologicalSpace.Opens.IsBasis.isOpenCover
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Set", "subset_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Opens.IsBasis.isOpenCover_mem_and_le {S : Set (Opens X)} (hS : Opens.IsBasis S) {U : ι → Opens X} (hU : IsOpenCover U) : IsOpenCover (fun V : { x : Opens X × ι // x.1 ∈ S ∧ x.1 ≤ U x.2 } ↦ V.1.1)
by refine top_le_iff.mp fun x _ ↦ ?_ obtain ⟨i, hxi⟩ := hU.exists_mem x obtain ⟨_, ⟨V, hV, rfl⟩, hxV, hVU⟩ := hS.exists_subset_of_mem_open hxi (U i).2 simp only [Opens.iSup_mk, Opens.carrier_eq_coe, Opens.mem_mk, Set.mem_iUnion, SetLike.mem_coe] exact ⟨⟨(V, i), hV, hVU⟩, hxV⟩
lemma
TopologicalSpace.Opens.IsBasis.isOpenCover_mem_and_le
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Set", "Set.mem_iUnion", "SetLike.mem_coe" ]
Given an open cover and a basis, the set of basis elements contained in any of the covers is still a cover.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsPreirreducible.of_subset_iUnion {X ι : Type*} [TopologicalSpace X] {U : ι → Opens X} (hn : Pairwise ((¬ Disjoint · ·) on U)) (h : ∀ i, IsPreirreducible ((U i) : Set X)) {s : Set X} (hs : IsOpen s) (hsU : s ⊆ ⋃ i, U i) : IsPreirreducible s
by rcases s.eq_empty_or_nonempty with he | hne · rw [he]; exact isPreirreducible_empty · choose x hx using hne choose i hi using mem_iUnion.mp <| hsU hx rcases exists_mem_irreducibleComponents_subset_of_isIrreducible (U i).carrier ⟨⟨x, hi⟩, h i⟩ with ⟨u, hu, hUu⟩ by_cases huniv : s ⊆ u · exa...
theorem
IsPreirreducible.of_subset_iUnion
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Disjoint", "IsOpen", "IsPreirreducible", "Pairwise", "Set", "TopologicalSpace", "by_cases", "exists_mem_irreducibleComponents_subset_of_isIrreducible", "isClosed_of_mem_irreducibleComponents", "isPreirreducible_empty" ]
(Pre)Irreducibility of an open set can be checked on a cover by opens with pairwise non-empty intersections.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PreirreducibleSpace.of_isOpenCover {X ι : Type*} [TopologicalSpace X] {U : ι → Opens X} (hn : Pairwise ((¬ Disjoint · ·) on U)) (hU : IsOpenCover U) (h : ∀ i, PreirreducibleSpace (U i)) : PreirreducibleSpace X
have h' (i : _) : IsPreirreducible (U i).carrier := IsPreirreducible.of_subtype ⟨IsPreirreducible.of_subset_iUnion hn h' isOpen_univ (by simpa using hU.iSup_set_eq_univ)⟩
theorem
PreirreducibleSpace.of_isOpenCover
Topology.Sets
Mathlib/Topology/Sets/OpenCover.lean
[]
[ "Disjoint", "IsPreirreducible", "IsPreirreducible.of_subtype", "Pairwise", "PreirreducibleSpace", "TopologicalSpace", "isOpen_univ" ]
(Pre)Irreducibility can be checked on an open cover with pairwise non-empty intersections.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Opens where /-- The underlying set of a bundled `TopologicalSpace.Opens` object. -/ carrier : Set α /-- The `TopologicalSpace.Opens.carrier _` is an open set. -/ is_open' : IsOpen carrier
structure
TopologicalSpace.Opens
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set" ]
The type of open subsets of a topological space.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instSecondCountableOpens [SecondCountableTopology α] (U : Opens α) : SecondCountableTopology U
inferInstanceAs (SecondCountableTopology U.1)
instance
TopologicalSpace.Opens.instSecondCountableOpens
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "SecondCountableTopology" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
«forall» {p : Opens α → Prop} : (∀ U, p U) ↔ ∀ (U : Set α) (hU : IsOpen U), p ⟨U, hU⟩
⟨fun h _ _ => h _, fun h _ => h _ _⟩
theorem
TopologicalSpace.Opens.«forall»
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
carrier_eq_coe (U : Opens α) : U.1 = ↑U
rfl
theorem
TopologicalSpace.Opens.carrier_eq_coe
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_mk {U : Set α} {hU : IsOpen U} : ↑(⟨U, hU⟩ : Opens α) = U
rfl
theorem
TopologicalSpace.Opens.coe_mk
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set" ]
the coercion `Opens α → Set α` applied to a pair is the same as taking the first component
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_mk {x : α} {U : Set α} {h : IsOpen U} : x ∈ mk U h ↔ x ∈ U
Iff.rfl
theorem
TopologicalSpace.Opens.mem_mk
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nonempty_coeSort {U : Opens α} : Nonempty U ↔ (U : Set α).Nonempty
Set.nonempty_coe_sort
theorem
TopologicalSpace.Opens.nonempty_coeSort
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "Set.nonempty_coe_sort" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nonempty_coe {U : Opens α} : (U : Set α).Nonempty ↔ ∃ x, x ∈ U
Iff.rfl
theorem
TopologicalSpace.Opens.nonempty_coe
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ext {U V : Opens α} (h : (U : Set α) = V) : U = V
SetLike.coe_injective h
theorem
TopologicalSpace.Opens.ext
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "SetLike.coe_injective" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_inj {U V : Opens α} : (U : Set α) = V ↔ U = V
SetLike.ext'_iff.symm
theorem
TopologicalSpace.Opens.coe_inj
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
inclusion {U V : Opens α} (h : U ≤ V) : U → V
Set.inclusion h
abbrev
TopologicalSpace.Opens.inclusion
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set.inclusion" ]
A version of `Set.inclusion` not requiring definitional abuse
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isOpen (U : Opens α) : IsOpen (U : Set α)
U.is_open'
theorem
TopologicalSpace.Opens.isOpen
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk_coe (U : Opens α) : mk (↑U) U.isOpen = U
rfl
theorem
TopologicalSpace.Opens.mk_coe
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Simps.coe (U : Opens α) : Set α
U initialize_simps_projections Opens (carrier → coe, as_prefix coe)
def
TopologicalSpace.Opens.Simps.coe
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
See Note [custom simps projection].
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
interior (s : Set α) : Opens α
⟨interior s, isOpen_interior⟩
def
TopologicalSpace.Opens.interior
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "interior" ]
The interior of a set, as an element of `Opens`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_interior {s : Set α} {x : α} : x ∈ Opens.interior s ↔ x ∈ _root_.interior s
.rfl
theorem
TopologicalSpace.Opens.mem_interior
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "mem_interior" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
gc : GaloisConnection ((↑) : Opens α → Set α) Opens.interior
fun U _ => ⟨fun h => interior_maximal h U.isOpen, fun h => le_trans h interior_subset⟩
theorem
TopologicalSpace.Opens.gc
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "GaloisConnection", "Set", "interior_maximal", "le_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
gi : GaloisCoinsertion (↑) (@Opens.interior α _)
where choice s hs := ⟨s, interior_eq_iff_isOpen.mp <| le_antisymm interior_subset hs⟩ gc := gc u_l_le _ := interior_subset choice_eq _s hs := le_antisymm hs interior_subset
def
TopologicalSpace.Opens.gi
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "GaloisCoinsertion", "interior_subset", "le_antisymm" ]
The Galois coinsertion between sets and opens.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk_inf_mk {U V : Set α} {hU : IsOpen U} {hV : IsOpen V} : (⟨U, hU⟩ ⊓ ⟨V, hV⟩ : Opens α) = ⟨U ⊓ V, IsOpen.inter hU hV⟩
rfl
theorem
TopologicalSpace.Opens.mk_inf_mk
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "IsOpen.inter", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_inf (s t : Opens α) : (↑(s ⊓ t) : Set α) = ↑s ∩ ↑t
rfl
theorem
TopologicalSpace.Opens.coe_inf
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_inf {s t : Opens α} {x : α} : x ∈ s ⊓ t ↔ x ∈ s ∧ x ∈ t
Iff.rfl
lemma
TopologicalSpace.Opens.mem_inf
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_sup (s t : Opens α) : (↑(s ⊔ t) : Set α) = ↑s ∪ ↑t
rfl
theorem
TopologicalSpace.Opens.coe_sup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_sup {s t : Opens α} {x : α} : x ∈ (s ⊔ t) ↔ x ∈ s ∨ x ∈ t
.rfl
theorem
TopologicalSpace.Opens.mem_sup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_bot : ((⊥ : Opens α) : Set α) = ∅
rfl
theorem
TopologicalSpace.Opens.coe_bot
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_bot {x : α} : x ∈ (⊥ : Opens α) ↔ False
Iff.rfl
lemma
TopologicalSpace.Opens.mem_bot
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk_empty : (⟨∅, isOpen_empty⟩ : Opens α) = ⊥
rfl
theorem
TopologicalSpace.Opens.mk_empty
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_eq_empty {U : Opens α} : (U : Set α) = ∅ ↔ U = ⊥
SetLike.coe_injective.eq_iff' rfl
theorem
TopologicalSpace.Opens.coe_eq_empty
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_top (x : α) : x ∈ (⊤ : Opens α)
trivial
lemma
TopologicalSpace.Opens.mem_top
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_top : ((⊤ : Opens α) : Set α) = Set.univ
rfl
theorem
TopologicalSpace.Opens.coe_top
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "Set.univ" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk_univ : (⟨univ, isOpen_univ⟩ : Opens α) = ⊤
rfl
theorem
TopologicalSpace.Opens.mk_univ
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_eq_univ {U : Opens α} : (U : Set α) = univ ↔ U = ⊤
SetLike.coe_injective.eq_iff' rfl
theorem
TopologicalSpace.Opens.coe_eq_univ
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_sSup {S : Set (Opens α)} : (↑(sSup S) : Set α) = ⋃ i ∈ S, ↑i
rfl
theorem
TopologicalSpace.Opens.coe_sSup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_finset_sup (f : ι → Opens α) (s : Finset ι) : (↑(s.sup f) : Set α) = s.sup ((↑) ∘ f)
map_finset_sup (⟨⟨(↑), coe_sup⟩, coe_bot⟩ : SupBotHom (Opens α) (Set α)) _ _
theorem
TopologicalSpace.Opens.coe_finset_sup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Finset", "Set", "SupBotHom", "map_finset_sup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_finset_inf (f : ι → Opens α) (s : Finset ι) : (↑(s.inf f) : Set α) = s.inf ((↑) ∘ f)
map_finset_inf (⟨⟨(↑), coe_inf⟩, coe_top⟩ : InfTopHom (Opens α) (Set α)) _ _
theorem
TopologicalSpace.Opens.coe_finset_inf
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Finset", "InfTopHom", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_disjoint {s t : Opens α} : Disjoint (s : Set α) t ↔ Disjoint s t
by simp [disjoint_iff, ← SetLike.coe_set_eq]
lemma
TopologicalSpace.Opens.coe_disjoint
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Disjoint", "Set", "SetLike.coe_set_eq", "disjoint_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_iSup {ι} (s : ι → Opens α) : ((⨆ i, s i : Opens α) : Set α) = ⋃ i, s i
by simp [iSup]
theorem
TopologicalSpace.Opens.coe_iSup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iSup_def {ι} (s : ι → Opens α) : ⨆ i, s i = ⟨⋃ i, s i, isOpen_iUnion fun i => (s i).2⟩
ext <| coe_iSup s
theorem
TopologicalSpace.Opens.iSup_def
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "isOpen_iUnion" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iSup_mk {ι} (s : ι → Set α) (h : ∀ i, IsOpen (s i)) : (⨆ i, ⟨s i, h i⟩ : Opens α) = ⟨⋃ i, s i, isOpen_iUnion h⟩
iSup_def _
theorem
TopologicalSpace.Opens.iSup_mk
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set", "isOpen_iUnion" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_iSup {ι} {x : α} {s : ι → Opens α} : x ∈ iSup s ↔ ∃ i, x ∈ s i
by rw [← SetLike.mem_coe] simp
theorem
TopologicalSpace.Opens.mem_iSup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "SetLike.mem_coe", "iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_sSup {Us : Set (Opens α)} {x : α} : x ∈ sSup Us ↔ ∃ u ∈ Us, x ∈ u
by simp_rw [sSup_eq_iSup, mem_iSup, exists_prop]
theorem
TopologicalSpace.Opens.mem_sSup
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "sSup_eq_iSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
frameMinimalAxioms : Frame.MinimalAxioms (Opens α)
where inf_sSup_le_iSup_inf a s := (ext <| by simp only [coe_inf, coe_iSup, coe_sSup, Set.inter_iUnion₂]).le
def
TopologicalSpace.Opens.frameMinimalAxioms
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set.inter_iUnion₂" ]
Open sets in a topological space form a frame.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
instFrame : Frame (Opens α)
fast_instance% .ofMinimalAxioms frameMinimalAxioms
instance
TopologicalSpace.Opens.instFrame
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "ofMinimalAxioms" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
frameHom : FrameHom (Opens α) (Set α)
where toFun := (·) map_inf' _ _ := rfl map_top' := rfl map_sSup' _ := by simp
def
TopologicalSpace.Opens.frameHom
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "FrameHom", "Set" ]
The coercion from open sets to sets as a `FrameHom`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isOpenEmbedding' (U : Opens α) : IsOpenEmbedding (Subtype.val : U → α)
U.isOpen.isOpenEmbedding_subtypeVal
theorem
TopologicalSpace.Opens.isOpenEmbedding'
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isOpenEmbedding_of_le {U V : Opens α} (i : U ≤ V) : IsOpenEmbedding (Set.inclusion <| SetLike.coe_subset_coe.2 i)
where toIsEmbedding := .inclusion i isOpen_range := by rw [Set.range_inclusion i] exact U.isOpen.preimage continuous_subtype_val
theorem
TopologicalSpace.Opens.isOpenEmbedding_of_le
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set.inclusion", "Set.range_inclusion", "continuous_subtype_val" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
not_nonempty_iff_eq_bot (U : Opens α) : ¬Set.Nonempty (U : Set α) ↔ U = ⊥
by rw [← coe_inj, coe_bot, ← Set.not_nonempty_iff_eq_empty]
theorem
TopologicalSpace.Opens.not_nonempty_iff_eq_bot
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "Set.Nonempty", "Set.not_nonempty_iff_eq_empty" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ne_bot_iff_nonempty (U : Opens α) : U ≠ ⊥ ↔ Set.Nonempty (U : Set α)
by rw [Ne, ← not_nonempty_iff_eq_bot, not_not]
theorem
TopologicalSpace.Opens.ne_bot_iff_nonempty
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "Set.Nonempty" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eq_bot_or_top [IndiscreteTopology α] (U : Opens α) : U = ⊥ ∨ U = ⊤
by rw [← coe_eq_empty, ← coe_eq_univ, ← IndiscreteTopology.isOpen_iff] exact U.2
theorem
TopologicalSpace.Opens.eq_bot_or_top
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IndiscreteTopology", "IndiscreteTopology.isOpen_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsBasis (B : Set (Opens α)) : Prop
IsTopologicalBasis (((↑) : _ → Set α) '' B)
def
TopologicalSpace.Opens.IsBasis
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
A set of `opens α` is a basis if the set of corresponding sets is a topological basis.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBasis_iff_nbhd {B : Set (Opens α)} : IsBasis B ↔ ∀ {U : Opens α} {x}, x ∈ U → ∃ U' ∈ B, x ∈ U' ∧ U' ≤ U
by constructor <;> intro h · rintro ⟨sU, hU⟩ x hx rcases h.mem_nhds_iff.mp (IsOpen.mem_nhds hU hx) with ⟨sV, ⟨⟨V, H₁, H₂⟩, hsV⟩⟩ refine ⟨V, H₁, ?_⟩ cases V dsimp at H₂ subst H₂ exact hsV · refine isTopologicalBasis_of_isOpen_of_nhds ?_ ?_ · rintro sU ⟨U, -, rfl⟩ exact U.2 · i...
theorem
TopologicalSpace.Opens.isBasis_iff_nbhd
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen.mem_nhds", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBasis_iff_cover {B : Set (Opens α)} : IsBasis B ↔ ∀ U : Opens α, ∃ Us, Us ⊆ B ∧ U = sSup Us
by constructor · intro hB U refine ⟨{ V : Opens α | V ∈ B ∧ V ≤ U }, fun U hU => hU.left, ext ?_⟩ rw [coe_sSup, hB.open_eq_sUnion' U.isOpen] simp_rw [sUnion_eq_biUnion, iUnion, mem_setOf_eq, iSup_and, iSup_image] rfl · intro h rw [isBasis_iff_nbhd] intro U x hx rcases h U with ⟨Us, hUs...
theorem
TopologicalSpace.Opens.isBasis_iff_cover
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "iSup_and", "iSup_image", "le_sSup" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsBasis.isCompact_open_iff_eq_finite_iUnion {ι : Type*} (b : ι → Opens α) (hb : IsBasis (Set.range b)) (hb' : ∀ i, IsCompact (b i : Set α)) (U : Set α) : IsCompact U ∧ IsOpen U ↔ ∃ s : Set ι, s.Finite ∧ U = ⋃ i ∈ s, b i
by apply isCompact_open_iff_eq_finite_iUnion_of_isTopologicalBasis fun i : ι => (b i).1 · convert! (config := { transparency := .default }) hb ext simp · exact hb'
theorem
TopologicalSpace.Opens.IsBasis.isCompact_open_iff_eq_finite_iUnion
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsCompact", "IsOpen", "Set", "Set.range", "isCompact_open_iff_eq_finite_iUnion_of_isTopologicalBasis" ]
If `α` has a basis consisting of compact opens, then an open set in `α` is compact open iff it is a finite union of some elements in the basis
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsBasis.exists_finite_of_isCompact {B : Set (Opens α)} (hB : IsBasis B) {U : Opens α} (hU : IsCompact U.1) : ∃ Us ⊆ B, Us.Finite ∧ U = sSup Us
by classical obtain ⟨Us', hsub, hsup⟩ := isBasis_iff_cover.mp hB U obtain ⟨t, ht⟩ := hU.elim_finite_subcover (fun s : Us' ↦ s.1) (fun s ↦ s.1.2) (by simp [hsup]) refine ⟨Finset.image Subtype.val t, subset_trans (by simp) hsub, Finset.finite_toSet _, ?_⟩ exact le_antisymm (subset_trans ht (by simp)) (le_trans ...
lemma
TopologicalSpace.Opens.IsBasis.exists_finite_of_isCompact
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Finset.finite_toSet", "IsCompact", "Set", "le_antisymm", "le_trans", "sSup_le_sSup", "subset_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsBasis.le_iff {α} {t₁ t₂ : TopologicalSpace α} {Us : Set (Opens α)} (hUs : @IsBasis α t₂ Us) : t₁ ≤ t₂ ↔ ∀ U ∈ Us, IsOpen[t₁] U
by conv_lhs => rw [hUs.eq_generateFrom] simp [Set.subset_def, le_generateFrom_iff_subset_isOpen]
lemma
TopologicalSpace.Opens.IsBasis.le_iff
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "IsOpen", "Set", "Set.subset_def", "TopologicalSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBasis_sigma {ι : Type*} {α : ι → Type*} [∀ i, TopologicalSpace (α i)] {B : ∀ i, Set (Opens (α i))} (hB : ∀ i, IsBasis (B i)) : IsBasis (⋃ i : ι, (fun U ↦ ⟨Sigma.mk i '' U.1, isOpenMap_sigmaMk _ U.2⟩) '' B i)
by convert! TopologicalSpace.IsTopologicalBasis.sigma hB simp only [IsBasis, Set.image_iUnion, ← Set.image_comp] simp
lemma
TopologicalSpace.Opens.isBasis_sigma
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set", "Set.image_comp", "Set.image_iUnion", "TopologicalSpace", "TopologicalSpace.IsTopologicalBasis.sigma", "isOpenMap_sigmaMk" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsBasis.of_isInducing {B : Set (Opens β)} (H : IsBasis B) {f : α → β} (h : IsInducing f) : IsBasis { ⟨f ⁻¹' U, U.2.preimage h.continuous⟩ | U ∈ B }
by simp only [IsBasis] at H ⊢ convert! H.isInducing h ext; simp
lemma
TopologicalSpace.Opens.IsBasis.of_isInducing
Topology.Sets
Mathlib/Topology/Sets/Opens.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319