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uniformity_eq_symm : 𝓤 α = map Prod.swap (𝓤 α)
le_antisymm uniformity_le_symm symm_le_uniformity
theorem
uniformity_eq_symm
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "le_antisymm", "symm_le_uniformity", "uniformity_le_symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comap_swap_uniformity : comap (@Prod.swap α α) (𝓤 α) = 𝓤 α
(congr_arg _ uniformity_eq_symm).trans <| comap_map Prod.swap_injective
theorem
comap_swap_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Prod.swap_injective", "comap", "trans", "uniformity_eq_symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
symmetrize_mem_uniformity {V : SetRel α α} (h : V ∈ 𝓤 α) : SetRel.symmetrize V ∈ 𝓤 α
by apply (𝓤 α).inter_sets h rw [← comap_swap_uniformity] exact preimage_mem_comap h
theorem
symmetrize_mem_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.symmetrize", "comap_swap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.hasBasis_symmetric : (𝓤 α).HasBasis (fun s : SetRel α α => s ∈ 𝓤 α ∧ SetRel.IsSymm s) id
hasBasis_self.2 fun t t_in => ⟨SetRel.symmetrize t, symmetrize_mem_uniformity t_in, inferInstance, SetRel.symmetrize_subset_self⟩
theorem
UniformSpace.hasBasis_symmetric
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.IsSymm", "symmetrize_mem_uniformity" ]
Symmetric entourages form a basis of `𝓤 α`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformity_lift_le_swap {g : SetRel α α → Filter β} {f : Filter β} (hg : Monotone g) (h : ((𝓤 α).lift fun s => g (preimage Prod.swap s)) ≤ f) : (𝓤 α).lift g ≤ f
calc (𝓤 α).lift g ≤ (Filter.map (@Prod.swap α α) <| 𝓤 α).lift g := lift_mono uniformity_le_symm le_rfl _ ≤ _ := by rw [map_lift_eq2 hg, image_swap_eq_preimage_swap]; exact h
theorem
uniformity_lift_le_swap
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Filter", "Filter.map", "Monotone", "SetRel", "le_rfl", "uniformity_le_symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformity_lift_le_comp {f : SetRel α α → Filter β} (h : Monotone f) : ((𝓤 α).lift fun s => f (s ○ s)) ≤ (𝓤 α).lift f
calc ((𝓤 α).lift fun s => f (s ○ s)) = ((𝓤 α).lift' fun s : SetRel α α => s ○ s).lift f := by rw [lift_lift'_assoc] · exact monotone_id.relComp monotone_id · exact h _ ≤ (𝓤 α).lift f := lift_mono comp_le_uniformity le_rfl
theorem
uniformity_lift_le_comp
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Filter", "Monotone", "SetRel", "comp_le_uniformity", "le_rfl", "monotone_id" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp3_mem_uniformity {s : SetRel α α} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, t ○ (t ○ t) ⊆ s
let ⟨_t', ht', ht's⟩ := comp_mem_uniformity_sets hs let ⟨t, ht, htt'⟩ := comp_mem_uniformity_sets ht' have := isRefl_of_mem_uniformity ht ⟨t, ht, (SetRel.comp_subset_comp (SetRel.left_subset_comp.trans htt') htt').trans ht's⟩
theorem
comp3_mem_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.comp_subset_comp", "comp_mem_uniformity_sets", "isRefl_of_mem_uniformity", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_le_uniformity3 : ((𝓤 α).lift' fun s : SetRel α α => s ○ (s ○ s)) ≤ 𝓤 α
fun _ h => let ⟨_t, htU, ht⟩ := comp3_mem_uniformity h mem_of_superset (mem_lift' htU) ht
theorem
comp_le_uniformity3
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "comp3_mem_uniformity" ]
See also `comp3_mem_uniformity`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_symm_mem_uniformity_sets {s : SetRel α α} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, SetRel.IsSymm t ∧ t ○ t ⊆ s
by obtain ⟨w, w_in, w_sub⟩ : ∃ w ∈ 𝓤 α, w ○ w ⊆ s := comp_mem_uniformity_sets hs use SetRel.symmetrize w, symmetrize_mem_uniformity w_in, inferInstance have : SetRel.symmetrize w ⊆ w := SetRel.symmetrize_subset_self calc SetRel.symmetrize w ○ SetRel.symmetrize w _ ⊆ w ○ w := by gcongr _ ⊆ s := w_sub
theorem
comp_symm_mem_uniformity_sets
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.IsSymm", "SetRel.symmetrize", "SetRel.symmetrize_subset_self", "comp_mem_uniformity_sets", "symmetrize_mem_uniformity" ]
See also `comp_open_symm_mem_uniformity_sets`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
subset_comp_self_of_mem_uniformity {s : SetRel α α} (h : s ∈ 𝓤 α) : s ⊆ s ○ s
have := isRefl_of_mem_uniformity h; SetRel.left_subset_comp
theorem
subset_comp_self_of_mem_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.left_subset_comp", "isRefl_of_mem_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_comp_symm_mem_uniformity_sets {s : SetRel α α} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, SetRel.IsSymm t ∧ t ○ t ○ t ⊆ s
by rcases comp_symm_mem_uniformity_sets hs with ⟨w, w_in, _, w_sub⟩ rcases comp_symm_mem_uniformity_sets w_in with ⟨t, t_in, t_symm, t_sub⟩ use t, t_in, t_symm have : t ⊆ t ○ t := subset_comp_self_of_mem_uniformity t_in calc t ○ t ○ t ⊆ w ○ (t ○ t) := by gcongr _ ⊆ w ○ w := by gcongr _ ⊆ s := w_su...
theorem
comp_comp_symm_mem_uniformity_sets
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.IsSymm", "comp_symm_mem_uniformity_sets", "subset_comp_self_of_mem_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball (x : β) (V : Set (β × β)) : Set β
Prod.mk x ⁻¹' V
def
UniformSpace.ball
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
The ball around `(x : β)` with respect to `(V : Set (β × β))`. Intended to be used for `V ∈ 𝓤 β`, but this is not needed for the definition. Recovers the notions of metric space ball when `V = {p | dist p.1 p.2 < r }`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_ball_self (x : α) {V : SetRel α α} : V ∈ 𝓤 α → x ∈ ball x V
refl_mem_uniformity
lemma
UniformSpace.mem_ball_self
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "refl_mem_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_ball_comp {V W : Set (β × β)} {x y z} (h : y ∈ ball x V) (h' : z ∈ ball y W) : z ∈ ball x (V ○ W)
SetRel.prodMk_mem_comp h h'
theorem
UniformSpace.mem_ball_comp
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel.prodMk_mem_comp" ]
The triangle inequality for `UniformSpace.ball`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_subset_of_comp_subset {V W : Set (β × β)} {x y} (h : x ∈ ball y W) (h' : W ○ W ⊆ V) : ball x W ⊆ ball y V
fun _z z_in => h' (mem_ball_comp h z_in)
theorem
UniformSpace.ball_subset_of_comp_subset
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_mono {V W : Set (β × β)} (h : V ⊆ W) (x : β) : ball x V ⊆ ball x W
preimage_mono h
theorem
UniformSpace.ball_mono
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_inter (x : β) (V W : Set (β × β)) : ball x (V ∩ W) = ball x V ∩ ball x W
preimage_inter
theorem
UniformSpace.ball_inter
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_inter_left (x : β) (V W : Set (β × β)) : ball x (V ∩ W) ⊆ ball x V
ball_mono inter_subset_left x
theorem
UniformSpace.ball_inter_left
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_inter_right (x : β) (V W : Set (β × β)) : ball x (V ∩ W) ⊆ ball x W
ball_mono inter_subset_right x
theorem
UniformSpace.ball_inter_right
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_iInter {x : β} {V : ι → Set (β × β)} : ball x (⋂ i, V i) = ⋂ i, ball x (V i)
preimage_iInter
theorem
UniformSpace.ball_iInter
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_ball_symmetry {V : SetRel β β} [V.IsSymm] {x y} : x ∈ ball y V ↔ y ∈ ball x V
V.comm
theorem
UniformSpace.mem_ball_symmetry
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_eq_of_symmetry {V : SetRel β β} [V.IsSymm] {x} : ball x V = { y | (y, x) ∈ V }
by ext y rw [mem_ball_symmetry] exact Iff.rfl
theorem
UniformSpace.ball_eq_of_symmetry
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_comp_of_mem_ball {V W : SetRel β β} {x y z : β} [V.IsSymm] (hx : x ∈ ball z V) (hy : y ∈ ball z W) : (x, y) ∈ V ○ W
by rw [mem_ball_symmetry] at hx exact ⟨z, hx, hy⟩
theorem
UniformSpace.mem_comp_of_mem_ball
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_comp_comp {V W M : SetRel β β} [W.IsSymm] {p : β × β} : p ∈ V ○ M ○ W ↔ (ball p.1 V ×ˢ ball p.2 W ∩ M).Nonempty
by obtain ⟨x, y⟩ := p constructor · rintro ⟨z, ⟨w, hpw, hwz⟩, hzy⟩ exact ⟨(w, z), ⟨hpw, by rwa [mem_ball_symmetry]⟩, hwz⟩ · rintro ⟨⟨w, z⟩, ⟨w_in, z_in⟩, hwz⟩ rw [mem_ball_symmetry] at z_in exact ⟨z, ⟨w, w_in, hwz⟩, z_in⟩
theorem
UniformSpace.mem_comp_comp
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isCover_iff_subset_iUnion_ball {U : SetRel β β} [U.IsSymm] {s N : Set β} : U.IsCover s N ↔ s ⊆ ⋃ y ∈ N, ball y U
by simp [SetRel.IsCover, subset_def, ball, U.comm] alias ⟨_root_.SetRel.IsCover.subset_iUnion_ball, _root_.SetRel.IsCover.of_subset_iUnion_ball⟩ := isCover_iff_subset_iUnion_ball
lemma
UniformSpace.isCover_iff_subset_iUnion_ball
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel", "SetRel.IsCover" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_nhds_uniformity_iff_right {x : α} {s : Set α} : s ∈ 𝓝 x ↔ { p : α × α | p.1 = x → p.2 ∈ s } ∈ 𝓤 α
by simp only [nhds_eq_comap_uniformity, mem_comap_prodMk]
theorem
mem_nhds_uniformity_iff_right
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_nhds_uniformity_iff_left {x : α} {s : Set α} : s ∈ 𝓝 x ↔ { p : α × α | p.2 = x → p.1 ∈ s } ∈ 𝓤 α
by rw [uniformity_eq_symm, mem_nhds_uniformity_iff_right] simp only [mem_map, preimage_setOf_eq, Prod.snd_swap, Prod.fst_swap]
theorem
mem_nhds_uniformity_iff_left
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "mem_nhds_uniformity_iff_right", "uniformity_eq_symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhdsWithin_eq_comap_uniformity_of_mem {x : α} {T : Set α} (hx : x ∈ T) (S : Set α) : 𝓝[S] x = (𝓤 α ⊓ 𝓟 (T ×ˢ S)).comap (Prod.mk x)
by simp [nhdsWithin, nhds_eq_comap_uniformity, hx]
theorem
nhdsWithin_eq_comap_uniformity_of_mem
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "comap", "nhdsWithin", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhdsWithin_eq_comap_uniformity {x : α} (S : Set α) : 𝓝[S] x = (𝓤 α ⊓ 𝓟 (univ ×ˢ S)).comap (Prod.mk x)
nhdsWithin_eq_comap_uniformity_of_mem (mem_univ _) S
theorem
nhdsWithin_eq_comap_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "comap", "nhdsWithin_eq_comap_uniformity_of_mem" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isOpen_iff_ball_subset {s : Set α} : IsOpen s ↔ ∀ x ∈ s, ∃ V ∈ 𝓤 α, ball x V ⊆ s
by simp_rw [isOpen_iff_mem_nhds, nhds_eq_comap_uniformity, mem_comap, ball]
theorem
isOpen_iff_ball_subset
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "IsOpen", "Set", "isOpen_iff_mem_nhds", "nhds_eq_comap_uniformity" ]
See also `isOpen_iff_isOpen_ball_subset`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_basis_uniformity' {p : ι → Prop} {s : ι → SetRel α α} (h : (𝓤 α).HasBasis p s) {x : α} : (𝓝 x).HasBasis p fun i => ball x (s i)
by rw [nhds_eq_comap_uniformity] exact h.comap (Prod.mk x)
theorem
nhds_basis_uniformity'
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_basis_uniformity {p : ι → Prop} {s : ι → SetRel α α} (h : (𝓤 α).HasBasis p s) {x : α} : (𝓝 x).HasBasis p fun i => { y | (y, x) ∈ s i }
by replace h := h.comap Prod.swap rw [comap_swap_uniformity] at h exact nhds_basis_uniformity' h
theorem
nhds_basis_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "comap_swap_uniformity", "nhds_basis_uniformity'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_eq_comap_uniformity' {x : α} : 𝓝 x = (𝓤 α).comap fun y => (y, x)
(nhds_basis_uniformity (𝓤 α).basis_sets).eq_of_same_basis <| (𝓤 α).basis_sets.comap _
theorem
nhds_eq_comap_uniformity'
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "comap", "nhds_basis_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.mem_nhds_iff {x : α} {s : Set α} : s ∈ 𝓝 x ↔ ∃ V ∈ 𝓤 α, ball x V ⊆ s
by rw [nhds_eq_comap_uniformity, mem_comap] simp_rw [ball]
theorem
UniformSpace.mem_nhds_iff
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.ball_mem_nhds (x : α) ⦃V : SetRel α α⦄ (V_in : V ∈ 𝓤 α) : ball x V ∈ 𝓝 x
by rw [UniformSpace.mem_nhds_iff] exact ⟨V, V_in, Subset.rfl⟩
theorem
UniformSpace.ball_mem_nhds
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "UniformSpace.mem_nhds_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.ball_mem_nhdsWithin {x : α} {S : Set α} ⦃V : SetRel α α⦄ (x_in : x ∈ S) (V_in : V ∈ 𝓤 α ⊓ 𝓟 (S ×ˢ S)) : ball x V ∈ 𝓝[S] x
by rw [nhdsWithin_eq_comap_uniformity_of_mem x_in, mem_comap] exact ⟨V, V_in, Subset.rfl⟩
theorem
UniformSpace.ball_mem_nhdsWithin
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel", "nhdsWithin_eq_comap_uniformity_of_mem" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.mem_nhds_iff_symm {x : α} {s : Set α} : s ∈ 𝓝 x ↔ ∃ V ∈ 𝓤 α, SetRel.IsSymm V ∧ ball x V ⊆ s
by rw [UniformSpace.mem_nhds_iff] constructor · rintro ⟨V, V_in, V_sub⟩ use SetRel.symmetrize V, symmetrize_mem_uniformity V_in, inferInstance exact Subset.trans (ball_mono SetRel.symmetrize_subset_self x) V_sub · rintro ⟨V, V_in, _, V_sub⟩ exact ⟨V, V_in, V_sub⟩
theorem
UniformSpace.mem_nhds_iff_symm
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel.IsSymm", "SetRel.symmetrize", "SetRel.symmetrize_subset_self", "UniformSpace.mem_nhds_iff", "symmetrize_mem_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.hasBasis_nhds (x : α) : HasBasis (𝓝 x) (fun s : SetRel α α => s ∈ 𝓤 α ∧ SetRel.IsSymm s) fun s => ball x s
⟨fun t => by simp [UniformSpace.mem_nhds_iff_symm, and_assoc]⟩
theorem
UniformSpace.hasBasis_nhds
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "SetRel.IsSymm", "UniformSpace.mem_nhds_iff_symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.mem_closure_iff_symm_ball {s : Set α} {x} : x ∈ closure s ↔ ∀ {V}, V ∈ 𝓤 α → SetRel.IsSymm V → (s ∩ ball x V).Nonempty
by simp [mem_closure_iff_nhds_basis (hasBasis_nhds x), Set.Nonempty]
theorem
UniformSpace.mem_closure_iff_symm_ball
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "Set.Nonempty", "SetRel.IsSymm", "closure", "mem_closure_iff_nhds_basis" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.mem_closure_iff_ball {s : Set α} {x} : x ∈ closure s ↔ ∀ {V}, V ∈ 𝓤 α → (ball x V ∩ s).Nonempty
by simp [mem_closure_iff_nhds_basis' (nhds_basis_uniformity' (𝓤 α).basis_sets)]
theorem
UniformSpace.mem_closure_iff_ball
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "closure", "mem_closure_iff_nhds_basis'", "nhds_basis_uniformity'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.closure_subset_preimage {U : SetRel α α} (hU : U ∈ 𝓤 α) (s : Set α) : closure s ⊆ U.preimage s
by intro x hx obtain ⟨y, hxy, hy⟩ := mem_closure_iff_ball.mp hx hU exact ⟨y, hy, hxy⟩
theorem
UniformSpace.closure_subset_preimage
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel", "closure" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformSpace.closure_subset_image {U : SetRel α α} (hU : U ∈ 𝓤 α) (s : Set α) : closure s ⊆ U.image s
closure_subset_preimage (symm_le_uniformity hU) s
theorem
UniformSpace.closure_subset_image
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel", "closure", "symm_le_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_eq_uniformity {x : α} : 𝓝 x = (𝓤 α).lift' (ball x)
(nhds_basis_uniformity' (𝓤 α).basis_sets).eq_biInf
theorem
nhds_eq_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "nhds_basis_uniformity'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_eq_uniformity' {x : α} : 𝓝 x = (𝓤 α).lift' fun s => { y | (y, x) ∈ s }
(nhds_basis_uniformity (𝓤 α).basis_sets).eq_biInf
theorem
nhds_eq_uniformity'
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "nhds_basis_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_nhds_left (x : α) {s : SetRel α α} (h : s ∈ 𝓤 α) : { y : α | (x, y) ∈ s } ∈ 𝓝 x
ball_mem_nhds x h
theorem
mem_nhds_left
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_nhds_right (y : α) {s : SetRel α α} (h : s ∈ 𝓤 α) : { x : α | (x, y) ∈ s } ∈ 𝓝 y
mem_nhds_left _ (symm_le_uniformity h)
theorem
mem_nhds_right
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "mem_nhds_left", "symm_le_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_mem_nhds_ball_subset_of_mem_nhds {a : α} {U : Set α} (h : U ∈ 𝓝 a) : ∃ V ∈ 𝓝 a, ∃ t ∈ 𝓤 α, ∀ a' ∈ V, UniformSpace.ball a' t ⊆ U
let ⟨t, ht, htU⟩ := comp_mem_uniformity_sets (mem_nhds_uniformity_iff_right.1 h) ⟨_, mem_nhds_left a ht, t, ht, fun a₁ h₁ a₂ h₂ => @htU (a, a₂) ⟨a₁, h₁, h₂⟩ rfl⟩
theorem
exists_mem_nhds_ball_subset_of_mem_nhds
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "UniformSpace.ball", "comp_mem_uniformity_sets", "mem_nhds_left" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_right_nhds_uniformity {a : α} : Tendsto (fun a' => (a', a)) (𝓝 a) (𝓤 α)
fun _ => mem_nhds_right a
theorem
tendsto_right_nhds_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "mem_nhds_right" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_left_nhds_uniformity {a : α} : Tendsto (fun a' => (a, a')) (𝓝 a) (𝓤 α)
fun _ => mem_nhds_left a
theorem
tendsto_left_nhds_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "mem_nhds_left" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
lift_nhds_left {x : α} {g : Set α → Filter β} (hg : Monotone g) : (𝓝 x).lift g = (𝓤 α).lift fun s : SetRel α α => g (ball x s)
by rw [nhds_eq_comap_uniformity, comap_lift_eq2 hg] simp_rw [ball, Function.comp_def]
theorem
lift_nhds_left
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Filter", "Monotone", "Set", "SetRel", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
lift_nhds_right {x : α} {g : Set α → Filter β} (hg : Monotone g) : (𝓝 x).lift g = (𝓤 α).lift fun s : SetRel α α => g { y | (y, x) ∈ s }
by rw [nhds_eq_comap_uniformity', comap_lift_eq2 hg] simp_rw [Function.comp_def, preimage]
theorem
lift_nhds_right
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Filter", "Monotone", "Set", "SetRel", "nhds_eq_comap_uniformity'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_nhds_eq_uniformity_uniformity_prod {a b : α} : 𝓝 a ×ˢ 𝓝 b = (𝓤 α).lift fun s : SetRel α α => (𝓤 α).lift' fun t => { y : α | (y, a) ∈ s } ×ˢ { y : α | (b, y) ∈ t }
by rw [nhds_eq_uniformity', nhds_eq_uniformity, prod_lift'_lift'] exacts [rfl, monotone_preimage, monotone_preimage]
theorem
nhds_nhds_eq_uniformity_uniformity_prod
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel", "nhds_eq_uniformity", "nhds_eq_uniformity'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Filter.HasBasis.biInter_biUnion_ball {p : ι → Prop} {U : ι → SetRel α α} (h : HasBasis (𝓤 α) p U) (s : Set α) : (⋂ (i) (_ : p i), ⋃ x ∈ s, ball x (U i)) = closure s
by ext x simp [mem_closure_iff_nhds_basis (nhds_basis_uniformity h), ball]
theorem
Filter.HasBasis.biInter_biUnion_ball
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel", "closure", "mem_closure_iff_nhds_basis", "nhds_basis_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformContinuous (f : α → β)
Tendsto (fun x : α × α => (f x.1, f x.2)) (𝓤 α) (𝓤 β) /-- Notation for uniform continuity with respect to non-standard `UniformSpace` instances. -/ scoped[Uniformity] notation "UniformContinuous[" u₁ ", " u₂ "]" => @UniformContinuous _ _ u₁ u₂
def
UniformContinuous
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[]
A function `f : α → β` is *uniformly continuous* if `(f x, f y)` tends to the diagonal as `(x, y)` tends to the diagonal. In other words, if `x` is sufficiently close to `y`, then `f x` is close to `f y` no matter where `x` and `y` are located in `α`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformContinuousOn (f : α → β) (s : Set α) : Prop
Tendsto (fun x : α × α => (f x.1, f x.2)) (𝓤 α ⊓ 𝓟 (s ×ˢ s)) (𝓤 β)
def
UniformContinuousOn
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set" ]
A function `f : α → β` is *uniformly continuous* on `s : Set α` if `(f x, f y)` tends to the diagonal as `(x, y)` tends to the diagonal while remaining in `s ×ˢ s`. In other words, if `x` is sufficiently close to `y`, then `f x` is close to `f y` no matter where `x` and `y` are located in `s`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_def {f : α → β} : UniformContinuous f ↔ ∀ r ∈ 𝓤 β, { x : α × α | (f x.1, f x.2) ∈ r } ∈ 𝓤 α
Iff.rfl
theorem
uniformContinuous_def
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "UniformContinuous" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_iff_eventually {f : α → β} : UniformContinuous f ↔ ∀ r ∈ 𝓤 β, ∀ᶠ x : α × α in 𝓤 α, (f x.1, f x.2) ∈ r
Iff.rfl
theorem
uniformContinuous_iff_eventually
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "UniformContinuous" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuousOn_univ {f : α → β} : UniformContinuousOn f univ ↔ UniformContinuous f
by rw [UniformContinuousOn, UniformContinuous, univ_prod_univ, principal_univ, inf_top_eq]
theorem
uniformContinuousOn_univ
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "UniformContinuous", "UniformContinuousOn" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_of_const {c : α → β} (h : ∀ a b, c a = c b) : UniformContinuous c
have : (fun x : α × α => (c x.fst, c x.snd)) ⁻¹' SetRel.id = univ := eq_univ_iff_forall.2 fun ⟨a, b⟩ => h a b le_trans (map_le_iff_le_comap.2 <| by simp [comap_principal, this]) refl_le_uniformity
theorem
uniformContinuous_of_const
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "SetRel.id", "UniformContinuous", "le_trans", "refl_le_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_id : UniformContinuous (@id α)
tendsto_id
theorem
uniformContinuous_id
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "UniformContinuous" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_const {b : β} : UniformContinuous fun _ : α => b
uniformContinuous_of_const fun _ _ => rfl
theorem
uniformContinuous_const
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "UniformContinuous", "uniformContinuous_of_const" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformContinuous.comp [UniformSpace γ] {g : β → γ} {f : α → β} (hg : UniformContinuous g) (hf : UniformContinuous f) : UniformContinuous (g ∘ f)
hg.comp hf
theorem
UniformContinuous.comp
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "UniformContinuous", "UniformSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformContinuous.iterate (T : β → β) (n : ℕ) (h : UniformContinuous T) : UniformContinuous T^[n]
by induction n with | zero => exact uniformContinuous_id | succ n hn => exact Function.iterate_succ _ _ ▸ UniformContinuous.comp hn h
theorem
UniformContinuous.iterate
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Function.iterate_succ", "UniformContinuous", "UniformContinuous.comp", "uniformContinuous_id" ]
If a function `T` is uniformly continuous in a uniform space `β`, then its `n`-th iterate `T^[n]` is also uniformly continuous.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Filter.HasBasis.uniformContinuous_iff {ι'} {p : ι → Prop} {s : ι → SetRel α α} (ha : (𝓤 α).HasBasis p s) {q : ι' → Prop} {t : ι' → Set (β × β)} (hb : (𝓤 β).HasBasis q t) {f : α → β} : UniformContinuous f ↔ ∀ i, q i → ∃ j, p j ∧ ∀ x y, (x, y) ∈ s j → (f x, f y) ∈ t i
(ha.tendsto_iff hb).trans <| by simp only [Prod.forall]
theorem
Filter.HasBasis.uniformContinuous_iff
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "SetRel", "UniformContinuous", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Filter.HasBasis.uniformContinuousOn_iff {ι'} {p : ι → Prop} {s : ι → SetRel α α} (ha : (𝓤 α).HasBasis p s) {q : ι' → Prop} {t : ι' → Set (β × β)} (hb : (𝓤 β).HasBasis q t) {f : α → β} {S : Set α} : UniformContinuousOn f S ↔ ∀ i, q i → ∃ j, p j ∧ ∀ x, x ∈ S → ∀ y, y ∈ S → (x, y) ∈ s j → (f x, f y) ∈ ...
((ha.inf_principal (S ×ˢ S)).tendsto_iff hb).trans <| by simp_rw [Prod.forall, Set.inter_comm (s _), forall_mem_comm, mem_inter_iff, mem_prod, and_imp]
theorem
Filter.HasBasis.uniformContinuousOn_iff
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "Set", "Set.inter_comm", "SetRel", "UniformContinuousOn", "forall_mem_comm", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsUniformInducing (f : α → β) : Prop where /-- The uniformity filter on the domain is the pullback of the uniformity filter on the codomain under `Prod.map f f`. -/ comap_uniformity : comap (fun x : α × α ↦ (f x.1, f x.2)) (𝓤 β) = 𝓤 α
structure
IsUniformInducing
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "comap" ]
A map `f : α → β` between uniform spaces is called *uniform inducing* if the uniformity filter on `α` is the pullback of the uniformity filter on `β` under `Prod.map f f`. If `α` is a separated space, then this implies that `f` is injective, hence it is a `IsUniformEmbedding`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsUniformEmbedding (f : α → β) : Prop extends IsUniformInducing f where /-- A uniform embedding is injective. -/ injective : Function.Injective f
structure
IsUniformEmbedding
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "IsUniformInducing" ]
A map `f : α → β` between uniform spaces is a *uniform embedding* if it is uniform inducing and injective. If `α` is a separated space, then the latter assumption follows from the former.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsUniformEmbedding.isUniformInducing {f : α → β} (hf : IsUniformEmbedding f) : IsUniformInducing f
hf.toIsUniformInducing
lemma
IsUniformEmbedding.isUniformInducing
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Defs.lean
[]
[ "IsUniformEmbedding", "IsUniformInducing" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoLocallyUniformly_of_forall_tendsto (hF_cont : ∀ i, Continuous (F i)) (hF_mono : Monotone F) (hf : Continuous f) (h_tendsto : ∀ x, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoLocallyUniformly F f atTop
by refine (atTop : Filter ι).eq_or_neBot.elim (fun h ↦ ?eq_bot) (fun _ ↦ ?_) case eq_bot => simp [h, tendstoLocallyUniformly_iff_forall_tendsto] have F_le_f (x : α) (n : ι) : F n x ≤ f x := by refine ge_of_tendsto (h_tendsto x) ?_ filter_upwards [Ici_mem_atTop n] with m hnm exact hF_mono hnm x simp_...
lemma
Monotone.tendstoLocallyUniformly_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Continuous", "Filter", "Metric.tendstoLocallyUniformly_iff", "Monotone", "TendstoLocallyUniformly", "continuous_const", "norm_le_norm_of_abs_le_abs", "tendstoLocallyUniformly_iff_forall_tendsto" ]
**Dini's theorem**: if `F n` is a monotone increasing collection of continuous functions converging pointwise to a continuous function `f`, then `F n` converges locally uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoLocallyUniformlyOn_of_forall_tendsto {s : Set α} (hF_cont : ∀ i, ContinuousOn (F i) s) (hF_mono : ∀ x ∈ s, Monotone (F · x)) (hf : ContinuousOn f s) (h_tendsto : ∀ x ∈ s, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoLocallyUniformlyOn F f atTop s
by rw [tendstoLocallyUniformlyOn_iff_tendstoLocallyUniformly_comp_coe] exact tendstoLocallyUniformly_of_forall_tendsto (hF_cont · |>.restrict) (fun _ _ h x ↦ hF_mono _ x.2 h) hf.restrict (fun x ↦ h_tendsto x x.2)
lemma
Monotone.tendstoLocallyUniformlyOn_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "ContinuousOn", "Monotone", "Set", "TendstoLocallyUniformlyOn", "tendstoLocallyUniformlyOn_iff_tendstoLocallyUniformly_comp_coe" ]
**Dini's theorem**: if `F n` is a monotone increasing collection of continuous functions on a set `s` converging pointwise to a continuous function `f`, then `F n` converges locally uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoUniformly_of_forall_tendsto [CompactSpace α] (hF_cont : ∀ i, Continuous (F i)) (hF_mono : Monotone F) (hf : Continuous f) (h_tendsto : ∀ x, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoUniformly F f atTop
tendstoLocallyUniformly_iff_tendstoUniformly_of_compactSpace.mp <| tendstoLocallyUniformly_of_forall_tendsto hF_cont hF_mono hf h_tendsto
lemma
Monotone.tendstoUniformly_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "CompactSpace", "Continuous", "Monotone", "TendstoUniformly" ]
**Dini's theorem**: if `F n` is a monotone increasing collection of continuous functions on a compact space converging pointwise to a continuous function `f`, then `F n` converges uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoUniformlyOn_of_forall_tendsto {s : Set α} (hs : IsCompact s) (hF_cont : ∀ i, ContinuousOn (F i) s) (hF_mono : ∀ x ∈ s, Monotone (F · x)) (hf : ContinuousOn f s) (h_tendsto : ∀ x ∈ s, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoUniformlyOn F f atTop s
tendstoLocallyUniformlyOn_iff_tendstoUniformlyOn_of_compact hs |>.mp <| tendstoLocallyUniformlyOn_of_forall_tendsto hF_cont hF_mono hf h_tendsto
lemma
Monotone.tendstoUniformlyOn_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "ContinuousOn", "IsCompact", "Monotone", "Set", "TendstoUniformlyOn", "tendstoLocallyUniformlyOn_iff_tendstoUniformlyOn_of_compact" ]
**Dini's theorem**: if `F n` is a monotone increasing collection of continuous functions on a compact set `s` converging pointwise to a continuous function `f`, then `F n` converges uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoLocallyUniformly_of_forall_tendsto (hF_cont : ∀ i, Continuous (F i)) (hF_anti : Antitone F) (hf : Continuous f) (h_tendsto : ∀ x, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoLocallyUniformly F f atTop
Monotone.tendstoLocallyUniformly_of_forall_tendsto (G := Gᵒᵈ) hF_cont hF_anti hf h_tendsto
lemma
Antitone.tendstoLocallyUniformly_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Antitone", "Continuous", "Monotone.tendstoLocallyUniformly_of_forall_tendsto", "TendstoLocallyUniformly" ]
**Dini's theorem**: if `F n` is a monotone decreasing collection of continuous functions on a converging pointwise to a continuous function `f`, then `F n` converges locally uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoLocallyUniformlyOn_of_forall_tendsto {s : Set α} (hF_cont : ∀ i, ContinuousOn (F i) s) (hF_anti : ∀ x ∈ s, Antitone (F · x)) (hf : ContinuousOn f s) (h_tendsto : ∀ x ∈ s, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoLocallyUniformlyOn F f atTop s
Monotone.tendstoLocallyUniformlyOn_of_forall_tendsto (G := Gᵒᵈ) hF_cont hF_anti hf h_tendsto
lemma
Antitone.tendstoLocallyUniformlyOn_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Antitone", "ContinuousOn", "Monotone.tendstoLocallyUniformlyOn_of_forall_tendsto", "Set", "TendstoLocallyUniformlyOn" ]
**Dini's theorem**: if `F n` is a monotone decreasing collection of continuous functions on a set `s` converging pointwise to a continuous function `f`, then `F n` converges locally uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoUniformly_of_forall_tendsto [CompactSpace α] (hF_cont : ∀ i, Continuous (F i)) (hF_anti : Antitone F) (hf : Continuous f) (h_tendsto : ∀ x, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoUniformly F f atTop
Monotone.tendstoUniformly_of_forall_tendsto (G := Gᵒᵈ) hF_cont hF_anti hf h_tendsto
lemma
Antitone.tendstoUniformly_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Antitone", "CompactSpace", "Continuous", "Monotone.tendstoUniformly_of_forall_tendsto", "TendstoUniformly" ]
**Dini's theorem**: if `F n` is a monotone decreasing collection of continuous functions on a compact space converging pointwise to a continuous function `f`, then `F n` converges uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendstoUniformlyOn_of_forall_tendsto {s : Set α} (hs : IsCompact s) (hF_cont : ∀ i, ContinuousOn (F i) s) (hF_anti : ∀ x ∈ s, Antitone (F · x)) (hf : ContinuousOn f s) (h_tendsto : ∀ x ∈ s, Tendsto (F · x) atTop (𝓝 (f x))) : TendstoUniformlyOn F f atTop s
Monotone.tendstoUniformlyOn_of_forall_tendsto (G := Gᵒᵈ) hs hF_cont hF_anti hf h_tendsto
lemma
Antitone.tendstoUniformlyOn_of_forall_tendsto
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Antitone", "ContinuousOn", "IsCompact", "Monotone.tendstoUniformlyOn_of_forall_tendsto", "Set", "TendstoUniformlyOn" ]
**Dini's theorem**: if `F n` is a monotone decreasing collection of continuous functions on a compact set `s` converging pointwise to a continuous `f`, then `F n` converges uniformly to `f`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_of_monotone_of_pointwise (hF_mono : Monotone F) (h_tendsto : ∀ x, Tendsto (F · x) atTop (𝓝 (f x))) : Tendsto F atTop (𝓝 f)
tendsto_of_tendstoLocallyUniformly <| hF_mono.tendstoLocallyUniformly_of_forall_tendsto (F · |>.continuous) f.continuous h_tendsto
lemma
ContinuousMap.tendsto_of_monotone_of_pointwise
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Monotone" ]
**Dini's theorem**: if `F n` is a monotone increasing collection of continuous functions converging pointwise to a continuous function `f`, then `F n` converges to `f` in the compact-open topology.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_of_antitone_of_pointwise (hF_anti : Antitone F) (h_tendsto : ∀ x, Tendsto (F · x) atTop (𝓝 (f x))) : Tendsto F atTop (𝓝 f)
tendsto_of_monotone_of_pointwise (G := Gᵒᵈ) hF_anti h_tendsto
lemma
ContinuousMap.tendsto_of_antitone_of_pointwise
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Dini.lean
[]
[ "Antitone" ]
**Dini's theorem**: if `F n` is a monotone decreasing collection of continuous functions converging pointwise to a continuous function `f`, then `F n` converges to `f` in the compact-open topology.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
DiscreteUniformity (X : Type*) [u : UniformSpace X] : Prop where eq_bot : u = ⊥
class
DiscreteUniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/DiscreteUniformity.lean
[]
[ "UniformSpace" ]
The discrete uniformity
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.discreteUniformity_iff_eq_principal_setRelId {X : Type*} [UniformSpace X] : DiscreteUniformity X ↔ uniformity X = 𝓟 SetRel.id
by rw [discreteUniformity_iff_eq_bot, UniformSpace.ext_iff, Filter.ext_iff, bot_uniformity] @[deprecated (since := "2025-12-19")] alias _root_.discreteUniformity_iff_eq_principal_relId := _root_.discreteUniformity_iff_eq_principal_setRelId
theorem
discreteUniformity_iff_eq_principal_setRelId
Topology.UniformSpace
Mathlib/Topology/UniformSpace/DiscreteUniformity.lean
[]
[ "DiscreteUniformity", "SetRel.id", "UniformSpace", "UniformSpace.ext_iff", "bot_uniformity", "uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eq_principal_setRelId : uniformity X = 𝓟 SetRel.id
discreteUniformity_iff_eq_principal_setRelId.mp inferInstance @[deprecated (since := "2025-12-19")] alias eq_principal_relId := eq_principal_setRelId
theorem
DiscreteUniformity.eq_principal_setRelId
Topology.UniformSpace
Mathlib/Topology/UniformSpace/DiscreteUniformity.lean
[]
[ "SetRel.id", "uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.discreteUniformity_iff_setRelId_mem_uniformity {X : Type*} [UniformSpace X] : DiscreteUniformity X ↔ SetRel.id ∈ uniformity X
by rw [← uniformSpace_eq_bot, discreteUniformity_iff_eq_bot] @[deprecated (since := "2025-12-19")] alias _root_.discreteUniformity_iff_relId_mem_uniformity := _root_.discreteUniformity_iff_setRelId_mem_uniformity
theorem
discreteUniformity_iff_setRelId_mem_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/DiscreteUniformity.lean
[]
[ "DiscreteUniformity", "SetRel.id", "UniformSpace", "uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
relId_mem_uniformity : SetRel.id ∈ uniformity X
discreteUniformity_iff_setRelId_mem_uniformity.mp inferInstance
theorem
DiscreteUniformity.relId_mem_uniformity
Topology.UniformSpace
Mathlib/Topology/UniformSpace/DiscreteUniformity.lean
[]
[ "SetRel.id", "uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous {Y : Type*} [UniformSpace Y] (f : X → Y) : UniformContinuous f
by simp only [uniformContinuous_iff_le_comap, DiscreteUniformity.eq_bot, bot_le]
theorem
DiscreteUniformity.uniformContinuous
Topology.UniformSpace
Mathlib/Topology/UniformSpace/DiscreteUniformity.lean
[]
[ "UniformContinuous", "UniformSpace", "uniformContinuous_iff_le_comap" ]
On a space with a discrete uniformity, any function is uniformly continuous.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
EquicontinuousAt (F : ι → X → α) (x₀ : X) : Prop
∀ U ∈ 𝓤 α, ∀ᶠ x in 𝓝 x₀, ∀ i, (F i x₀, F i x) ∈ U
def
EquicontinuousAt
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[]
A family `F : ι → X → α` of functions from a topological space to a uniform space is *equicontinuous at `x₀ : X`* if, for all entourages `U ∈ 𝓤 α`, there is a neighborhood `V` of `x₀` such that, for all `x ∈ V` and for all `i : ι`, `F i x` is `U`-close to `F i x₀`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Set.EquicontinuousAt (H : Set <| X → α) (x₀ : X) : Prop
EquicontinuousAt ((↑) : H → X → α) x₀
abbrev
Set.EquicontinuousAt
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousAt", "Set" ]
We say that a set `H : Set (X → α)` of functions is equicontinuous at a point if the family `(↑) : ↥H → (X → α)` is equicontinuous at that point.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
EquicontinuousWithinAt (F : ι → X → α) (S : Set X) (x₀ : X) : Prop
∀ U ∈ 𝓤 α, ∀ᶠ x in 𝓝[S] x₀, ∀ i, (F i x₀, F i x) ∈ U
def
EquicontinuousWithinAt
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "Set" ]
A family `F : ι → X → α` of functions from a topological space to a uniform space is *equicontinuous at `x₀ : X` within `S : Set X`* if, for all entourages `U ∈ 𝓤 α`, there is a neighborhood `V` of `x₀` within `S` such that, for all `x ∈ V` and for all `i : ι`, `F i x` is `U`-close to `F i x₀`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Set.EquicontinuousWithinAt (H : Set <| X → α) (S : Set X) (x₀ : X) : Prop
EquicontinuousWithinAt ((↑) : H → X → α) S x₀
abbrev
Set.EquicontinuousWithinAt
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousWithinAt", "Set" ]
We say that a set `H : Set (X → α)` of functions is equicontinuous at a point within a subset if the family `(↑) : ↥H → (X → α)` is equicontinuous at that point within that same subset.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Equicontinuous (F : ι → X → α) : Prop
∀ x₀, EquicontinuousAt F x₀
def
Equicontinuous
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousAt" ]
A family `F : ι → X → α` of functions from a topological space to a uniform space is *equicontinuous* on all of `X` if it is equicontinuous at each point of `X`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Set.Equicontinuous (H : Set <| X → α) : Prop
Equicontinuous ((↑) : H → X → α)
abbrev
Set.Equicontinuous
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "Equicontinuous", "Set" ]
We say that a set `H : Set (X → α)` of functions is equicontinuous if the family `(↑) : ↥H → (X → α)` is equicontinuous.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
EquicontinuousOn (F : ι → X → α) (S : Set X) : Prop
∀ x₀ ∈ S, EquicontinuousWithinAt F S x₀
def
EquicontinuousOn
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousWithinAt", "Set" ]
A family `F : ι → X → α` of functions from a topological space to a uniform space is *equicontinuous on `S : Set X`* if it is equicontinuous *within `S`* at each point of `S`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Set.EquicontinuousOn (H : Set <| X → α) (S : Set X) : Prop
EquicontinuousOn ((↑) : H → X → α) S
abbrev
Set.EquicontinuousOn
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousOn", "Set" ]
We say that a set `H : Set (X → α)` of functions is equicontinuous on a subset if the family `(↑) : ↥H → (X → α)` is equicontinuous on that subset.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformEquicontinuous (F : ι → β → α) : Prop
∀ U ∈ 𝓤 α, ∀ᶠ xy : β × β in 𝓤 β, ∀ i, (F i xy.1, F i xy.2) ∈ U
def
UniformEquicontinuous
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[]
A family `F : ι → β → α` of functions between uniform spaces is *uniformly equicontinuous* if, for all entourages `U ∈ 𝓤 α`, there is an entourage `V ∈ 𝓤 β` such that, whenever `x` and `y` are `V`-close, we have that, *for all `i : ι`*, `F i x` is `U`-close to `F i y`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Set.UniformEquicontinuous (H : Set <| β → α) : Prop
UniformEquicontinuous ((↑) : H → β → α)
abbrev
Set.UniformEquicontinuous
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "Set", "UniformEquicontinuous" ]
We say that a set `H : Set (X → α)` of functions is uniformly equicontinuous if the family `(↑) : ↥H → (X → α)` is uniformly equicontinuous.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
UniformEquicontinuousOn (F : ι → β → α) (S : Set β) : Prop
∀ U ∈ 𝓤 α, ∀ᶠ xy : β × β in 𝓤 β ⊓ 𝓟 (S ×ˢ S), ∀ i, (F i xy.1, F i xy.2) ∈ U
def
UniformEquicontinuousOn
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "Set" ]
A family `F : ι → β → α` of functions between uniform spaces is *uniformly equicontinuous on `S : Set β`* if, for all entourages `U ∈ 𝓤 α`, there is a relative entourage `V ∈ 𝓤 β ⊓ 𝓟 (S ×ˢ S)` such that, whenever `x` and `y` are `V`-close, we have that, *for all `i : ι`*, `F i x` is `U`-close to `F i y`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Set.UniformEquicontinuousOn (H : Set <| β → α) (S : Set β) : Prop
UniformEquicontinuousOn ((↑) : H → β → α) S
abbrev
Set.UniformEquicontinuousOn
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "Set", "UniformEquicontinuousOn" ]
We say that a set `H : Set (X → α)` of functions is uniformly equicontinuous on a subset if the family `(↑) : ↥H → (X → α)` is uniformly equicontinuous on that subset.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
EquicontinuousAt.equicontinuousWithinAt {F : ι → X → α} {x₀ : X} (H : EquicontinuousAt F x₀) (S : Set X) : EquicontinuousWithinAt F S x₀
fun U hU ↦ (H U hU).filter_mono inf_le_left
lemma
EquicontinuousAt.equicontinuousWithinAt
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousAt", "EquicontinuousWithinAt", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
EquicontinuousWithinAt.mono {F : ι → X → α} {x₀ : X} {S T : Set X} (H : EquicontinuousWithinAt F T x₀) (hST : S ⊆ T) : EquicontinuousWithinAt F S x₀
fun U hU ↦ (H U hU).filter_mono <| nhdsWithin_mono x₀ hST
lemma
EquicontinuousWithinAt.mono
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousWithinAt", "Set", "nhdsWithin_mono" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
equicontinuousWithinAt_univ (F : ι → X → α) (x₀ : X) : EquicontinuousWithinAt F univ x₀ ↔ EquicontinuousAt F x₀
by rw [EquicontinuousWithinAt, EquicontinuousAt, nhdsWithin_univ]
lemma
equicontinuousWithinAt_univ
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousAt", "EquicontinuousWithinAt", "nhdsWithin_univ" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
equicontinuousAt_restrict_iff (F : ι → X → α) {S : Set X} (x₀ : S) : EquicontinuousAt (S.restrict ∘ F) x₀ ↔ EquicontinuousWithinAt F S x₀
by simp [EquicontinuousWithinAt, EquicontinuousAt, ← eventually_nhds_subtype_iff]
lemma
equicontinuousAt_restrict_iff
Topology.UniformSpace
Mathlib/Topology/UniformSpace/Equicontinuity.lean
[]
[ "EquicontinuousAt", "EquicontinuousWithinAt", "Set", "eventually_nhds_subtype_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319