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tendsto_nhdsWithin_nhds [PseudoMetricSpace β] {f : α → β} {a b} : Tendsto f (𝓝[s] a) (𝓝 b) ↔ ∀ ε > 0, ∃ δ > 0, ∀ ⦃x : α⦄, x ∈ s → dist x a < δ → dist (f x) b < ε
by rw [← nhdsWithin_univ b, tendsto_nhdsWithin_nhdsWithin] simp only [mem_univ, true_and]
theorem
Metric.tendsto_nhdsWithin_nhds
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace", "nhdsWithin_univ" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_nhds_nhds [PseudoMetricSpace β] {f : α → β} {a b} : Tendsto f (𝓝 a) (𝓝 b) ↔ ∀ ε > 0, ∃ δ > 0, ∀ ⦃x : α⦄, dist x a < δ → dist (f x) b < ε
nhds_basis_ball.tendsto_iff nhds_basis_ball
theorem
Metric.tendsto_nhds_nhds
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuousAt_iff [PseudoMetricSpace β] {f : α → β} {a : α} : ContinuousAt f a ↔ ∀ ε > 0, ∃ δ > 0, ∀ ⦃x : α⦄, dist x a < δ → dist (f x) (f a) < ε
by rw [ContinuousAt, tendsto_nhds_nhds]
theorem
Metric.continuousAt_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ContinuousAt", "PseudoMetricSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuousWithinAt_iff [PseudoMetricSpace β] {f : α → β} {a : α} {s : Set α} : ContinuousWithinAt f s a ↔ ∀ ε > 0, ∃ δ > 0, ∀ ⦃x : α⦄, x ∈ s → dist x a < δ → dist (f x) (f a) < ε
by rw [ContinuousWithinAt, tendsto_nhdsWithin_nhds]
theorem
Metric.continuousWithinAt_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ContinuousWithinAt", "PseudoMetricSpace", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuousOn_iff [PseudoMetricSpace β] {f : α → β} {s : Set α} : ContinuousOn f s ↔ ∀ b ∈ s, ∀ ε > 0, ∃ δ > 0, ∀ a ∈ s, dist a b < δ → dist (f a) (f b) < ε
by simp [ContinuousOn, continuousWithinAt_iff]
theorem
Metric.continuousOn_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ContinuousOn", "PseudoMetricSpace", "Set", "continuousOn_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuous_iff [PseudoMetricSpace β] {f : α → β} : Continuous f ↔ ∀ b, ∀ ε > 0, ∃ δ > 0, ∀ a, dist a b < δ → dist (f a) (f b) < ε
continuous_iff_continuousAt.trans <| forall_congr' fun _ => tendsto_nhds_nhds
theorem
Metric.continuous_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Continuous", "PseudoMetricSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_nhds {f : Filter β} {u : β → α} {a : α} : Tendsto u f (𝓝 a) ↔ ∀ ε > 0, ∀ᶠ x in f, dist (u x) a < ε
nhds_basis_ball.tendsto_right_iff
theorem
Metric.tendsto_nhds
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Filter", "tendsto_nhds" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuousAt_iff' [TopologicalSpace β] {f : β → α} {b : β} : ContinuousAt f b ↔ ∀ ε > 0, ∀ᶠ x in 𝓝 b, dist (f x) (f b) < ε
by rw [ContinuousAt, tendsto_nhds]
theorem
Metric.continuousAt_iff'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ContinuousAt", "TopologicalSpace", "tendsto_nhds" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuousWithinAt_iff' [TopologicalSpace β] {f : β → α} {b : β} {s : Set β} : ContinuousWithinAt f s b ↔ ∀ ε > 0, ∀ᶠ x in 𝓝[s] b, dist (f x) (f b) < ε
by rw [ContinuousWithinAt, tendsto_nhds]
theorem
Metric.continuousWithinAt_iff'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ContinuousWithinAt", "Set", "TopologicalSpace", "tendsto_nhds" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuousOn_iff' [TopologicalSpace β] {f : β → α} {s : Set β} : ContinuousOn f s ↔ ∀ b ∈ s, ∀ ε > 0, ∀ᶠ x in 𝓝[s] b, dist (f x) (f b) < ε
by simp [ContinuousOn, continuousWithinAt_iff']
theorem
Metric.continuousOn_iff'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ContinuousOn", "Set", "TopologicalSpace", "continuousOn_iff'" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuous_iff' [TopologicalSpace β] {f : β → α} : Continuous f ↔ ∀ (a), ∀ ε > 0, ∀ᶠ x in 𝓝 a, dist (f x) (f a) < ε
continuous_iff_continuousAt.trans <| forall_congr' fun _ => tendsto_nhds
theorem
Metric.continuous_iff'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Continuous", "TopologicalSpace", "tendsto_nhds" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_atTop [Nonempty β] [SemilatticeSup β] {u : β → α} {a : α} : Tendsto u atTop (𝓝 a) ↔ ∀ ε > 0, ∃ N, ∀ n ≥ N, dist (u n) a < ε
(atTop_basis.tendsto_iff nhds_basis_ball).trans <| by simp only [true_and, mem_ball, mem_Ici]
theorem
Metric.tendsto_atTop
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "SemilatticeSup", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_atTop' [Nonempty β] [SemilatticeSup β] [NoMaxOrder β] {u : β → α} {a : α} : Tendsto u atTop (𝓝 a) ↔ ∀ ε > 0, ∃ N, ∀ n > N, dist (u n) a < ε
(atTop_basis_Ioi.tendsto_iff nhds_basis_ball).trans <| by simp only [true_and, gt_iff_lt, mem_Ioi, mem_ball]
theorem
Metric.tendsto_atTop'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "NoMaxOrder", "SemilatticeSup", "trans" ]
A variant of `tendsto_atTop` that uses `∃ N, ∀ n > N, ...` rather than `∃ N, ∀ n ≥ N, ...`
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isOpen_singleton_iff {α : Type*} [PseudoMetricSpace α] {x : α} : IsOpen ({x} : Set α) ↔ ∃ ε > 0, ∀ y, dist y x < ε → y = x
by simp [isOpen_iff, subset_singleton_iff, mem_ball]
theorem
Metric.isOpen_singleton_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "IsOpen", "PseudoMetricSpace", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.Dense.exists_dist_lt {s : Set α} (hs : Dense s) (x : α) {ε : ℝ} (hε : 0 < ε) : ∃ y ∈ s, dist x y < ε
by have : (ball x ε).Nonempty := by simp [hε] simpa only [mem_ball'] using hs.exists_mem_open isOpen_ball this
theorem
Dense.exists_dist_lt
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Dense", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.DenseRange.exists_dist_lt {β : Type*} {f : β → α} (hf : DenseRange f) (x : α) {ε : ℝ} (hε : 0 < ε) : ∃ y, dist x (f y) < ε
exists_range_iff.1 (hf.exists_dist_lt x hε)
theorem
DenseRange.exists_dist_lt
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "DenseRange" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformSpace_eq_bot : ‹PseudoMetricSpace α›.toUniformSpace = ⊥ ↔ ∃ r : ℝ, 0 < r ∧ Pairwise (r ≤ dist · · : α → α → Prop)
by simp only [uniformity_basis_dist.uniformSpace_eq_bot, mem_setOf_eq, not_lt]
lemma
Metric.uniformSpace_eq_bot
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Pairwise", "not_lt" ]
(Pseudo) metric space has discrete `UniformSpace` structure iff the distances between distinct points are uniformly bounded away from zero.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
DiscreteTopology.of_forall_le_dist {α} [PseudoMetricSpace α] {r : ℝ} (hpos : 0 < r) (hr : Pairwise (r ≤ dist · · : α → α → Prop)) : DiscreteTopology α
⟨by rw [Metric.uniformSpace_eq_bot.2 ⟨r, hpos, hr⟩, UniformSpace.toTopologicalSpace_bot]⟩
lemma
DiscreteTopology.of_forall_le_dist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "DiscreteTopology", "Pairwise", "PseudoMetricSpace", "UniformSpace.toTopologicalSpace_bot" ]
If the distances between distinct points in a (pseudo) metric space are uniformly bounded away from zero, then the space has discrete topology.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.uniformity_edist_aux {α} (d : α → α → ℝ≥0) : ⨅ ε > (0 : ℝ), 𝓟 { p : α × α | ↑(d p.1 p.2) < ε } = ⨅ ε > (0 : ℝ≥0∞), 𝓟 { p : α × α | ↑(d p.1 p.2) < ε }
by simp only [le_antisymm_iff, le_iInf_iff, le_principal_iff] refine ⟨fun ε hε => ?_, fun ε hε => ?_⟩ · rcases ENNReal.lt_iff_exists_nnreal_btwn.1 hε with ⟨ε', ε'0, ε'ε⟩ refine mem_iInf_of_mem (ε' : ℝ) (mem_iInf_of_mem (ENNReal.coe_pos.1 ε'0) ?_) exact fun x hx => lt_trans (ENNReal.coe_lt_coe.2 hx) ε'ε ...
theorem
Metric.uniformity_edist_aux
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "le_antisymm_iff", "le_of_lt", "lt_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.uniformity_edist : 𝓤 α = ⨅ ε > 0, 𝓟 { p : α × α | edist p.1 p.2 < ε }
by simp only [PseudoMetricSpace.uniformity_dist, dist_nndist, edist_nndist, Metric.uniformity_edist_aux]
theorem
Metric.uniformity_edist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Metric.uniformity_edist_aux", "dist_nndist", "edist_nndist" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.eball_top_eq_univ (x : α) : eball x ∞ = Set.univ
Set.eq_univ_iff_forall.mpr fun y => edist_lt_top y x
theorem
Metric.eball_top_eq_univ
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Set.univ", "edist_lt_top" ]
In a pseudometric space, an open ball of infinite radius is the whole space
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.eball_ofReal {x : α} {ε : ℝ} : eball x (.ofReal ε) = ball x ε
by ext y simp only [mem_eball, mem_ball, edist_dist] exact ENNReal.ofReal_lt_ofReal_iff_of_nonneg dist_nonneg @[deprecated (since := "2026-01-24")] alias Metric.emetric_ball := Metric.eball_ofReal
theorem
Metric.eball_ofReal
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ENNReal.ofReal_lt_ofReal_iff_of_nonneg", "dist_nonneg", "edist_dist" ]
Balls defined using the distance or the edistance coincide
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.eball_coe {x : α} {ε : ℝ≥0} : eball x ε = ball x ε
by rw [← eball_ofReal] simp @[deprecated (since := "2026-01-24")] alias Metric.emetric_ball_nnreal := Metric.eball_coe
theorem
Metric.eball_coe
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
Balls defined using the distance or the edistance coincide
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.closedEBall_ofReal {x : α} {ε : ℝ} (h : 0 ≤ ε) : closedEBall x (.ofReal ε) = closedBall x ε
by ext y; simp [edist_le_ofReal h] @[deprecated (since := "2026-01-24")] alias Metric.emetric_closedBall := Metric.closedEBall_ofReal
theorem
Metric.closedEBall_ofReal
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "edist_le_ofReal" ]
Closed balls defined using the distance or the edistance coincide
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.closedEBall_coe {x : α} {ε : ℝ≥0} : closedEBall x ε = closedBall x ε
by rw [← closedEBall_ofReal ε.coe_nonneg, ENNReal.ofReal_coe_nnreal] @[deprecated (since := "2026-01-24")] alias Metric.emetric_closedBall_nnreal := Metric.closedEBall_coe
theorem
Metric.closedEBall_coe
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ENNReal.ofReal_coe_nnreal" ]
Closed balls defined using the distance or the edistance coincide
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.eball_top (x : α) : eball x ⊤ = univ
eq_univ_of_forall fun _ => edist_lt_top _ _ @[deprecated (since := "2026-01-24")] alias Metric.emetric_ball_top := Metric.eball_top
theorem
Metric.eball_top
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "edist_lt_top" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.replaceUniformity {α} [U : UniformSpace α] (m : PseudoMetricSpace α) (H : 𝓤[U] = 𝓤[PseudoEMetricSpace.toUniformSpace]) : PseudoMetricSpace α
{ m with toUniformSpace := U uniformity_dist := H.trans PseudoMetricSpace.uniformity_dist }
abbrev
PseudoMetricSpace.replaceUniformity
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace", "UniformSpace" ]
Build a new pseudometric space from an old one where the bundled uniform structure is provably (but typically non-definitionaly) equal to some given uniform structure. See Note [forgetful inheritance]. See Note [reducible non-instances].
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.replaceUniformity_eq {α} [U : UniformSpace α] (m : PseudoMetricSpace α) (H : 𝓤[U] = 𝓤[PseudoEMetricSpace.toUniformSpace]) : m.replaceUniformity H = m
by ext rfl
theorem
PseudoMetricSpace.replaceUniformity_eq
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace", "UniformSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.replaceTopology {γ} [U : TopologicalSpace γ] (m : PseudoMetricSpace γ) (H : U = m.toUniformSpace.toTopologicalSpace) : PseudoMetricSpace γ
@PseudoMetricSpace.replaceUniformity γ (m.toUniformSpace.replaceTopology H) m rfl
abbrev
PseudoMetricSpace.replaceTopology
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace", "PseudoMetricSpace.replaceUniformity", "TopologicalSpace" ]
Build a new pseudometric space from an old one where the bundled topological structure is provably (but typically non-definitionaly) equal to some given topological structure. See Note [forgetful inheritance]. See Note [reducible non-instances].
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.replaceTopology_eq {γ} [U : TopologicalSpace γ] (m : PseudoMetricSpace γ) (H : U = m.toUniformSpace.toTopologicalSpace) : m.replaceTopology H = m
by ext rfl
theorem
PseudoMetricSpace.replaceTopology_eq
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace", "TopologicalSpace" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoEMetricSpace.toPseudoMetricSpaceOfDist {X : Type*} [e : PseudoEMetricSpace X] (dist : X → X → ℝ) (dist_nonneg : ∀ x y, 0 ≤ dist x y) (h : ∀ x y, edist x y = .ofReal (dist x y)) : PseudoMetricSpace X
where dist := dist dist_self x := by simpa [h, (dist_nonneg _ _).ge_iff_eq', -edist_self] using edist_self x dist_comm x y := by simpa [h, dist_nonneg] using edist_comm x y dist_triangle x y z := by simpa [h, dist_nonneg, add_nonneg, ← ENNReal.ofReal_add] using edist_triangle x y z edist := edist edist_...
abbrev
PseudoEMetricSpace.toPseudoMetricSpaceOfDist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ENNReal.coe_toNNReal_eq_toReal", "ENNReal.ofReal_add", "Metric.uniformity_edist_aux", "PseudoEMetricSpace", "PseudoMetricSpace", "dist_comm", "dist_nonneg", "dist_self", "dist_triangle", "edist_dist", "symm" ]
One gets a pseudometric space from an emetric space if the edistance is everywhere finite, by pushing the edistance to reals. We set it up so that the edist and the uniformity are defeq in the pseudometric space and the pseudoemetric space. In this definition, the distance is given separately, to be able to prescribe s...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoEMetricSpace.toPseudoMetricSpace {α : Type u} [PseudoEMetricSpace α] (h : ∀ x y : α, edist x y ≠ ⊤) : PseudoMetricSpace α
PseudoEMetricSpace.toPseudoMetricSpaceOfDist (ENNReal.toReal <| edist · ·) (by simp) (by simp [h])
abbrev
PseudoEMetricSpace.toPseudoMetricSpace
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "ENNReal.toReal", "PseudoEMetricSpace", "PseudoEMetricSpace.toPseudoMetricSpaceOfDist", "PseudoMetricSpace" ]
One gets a pseudometric space from an emetric space if the edistance is everywhere finite, by pushing the edistance to reals. We set it up so that the edist and the uniformity are defeq in the pseudometric space and the emetric space.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.replaceBornology {α} [B : Bornology α] (m : PseudoMetricSpace α) (H : ∀ s, @IsBounded _ B s ↔ @IsBounded _ PseudoMetricSpace.toBornology s) : PseudoMetricSpace α
{ m with toBornology := B cobounded_sets := Set.ext <| compl_surjective.forall.2 fun s => (H s).trans <| by rw [isBounded_iff, mem_setOf_eq, compl_compl] }
abbrev
PseudoMetricSpace.replaceBornology
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Bornology", "PseudoMetricSpace", "Set.ext", "compl_compl", "trans" ]
Build a new pseudometric space from an old one where the bundled bornology structure is provably (but typically non-definitionaly) equal to some given bornology structure. See Note [forgetful inheritance]. See Note [reducible non-instances].
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.replaceBornology_eq {α} [m : PseudoMetricSpace α] [B : Bornology α] (H : ∀ s, @IsBounded _ B s ↔ @IsBounded _ PseudoMetricSpace.toBornology s) : PseudoMetricSpace.replaceBornology _ H = m
by ext rfl
theorem
PseudoMetricSpace.replaceBornology_eq
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Bornology", "PseudoMetricSpace", "PseudoMetricSpace.replaceBornology" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.pseudoMetricSpace : PseudoMetricSpace ℝ
where dist x y := |x - y| dist_self := by simp [abs_zero] dist_comm _ _ := abs_sub_comm _ _ dist_triangle _ _ _ := abs_sub_le _ _ _
instance
Real.pseudoMetricSpace
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "PseudoMetricSpace", "dist_comm", "dist_self", "dist_triangle" ]
Instantiate the reals as a pseudometric space.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.dist_eq (x y : ℝ) : dist x y = |x - y|
rfl
theorem
Real.dist_eq
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.nndist_eq (x y : ℝ) : nndist x y = Real.nnabs (x - y)
rfl
theorem
Real.nndist_eq
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.nnabs" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.nndist_eq' (x y : ℝ) : nndist x y = Real.nnabs (y - x)
nndist_comm _ _
theorem
Real.nndist_eq'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.nnabs", "nndist_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.dist_0_eq_abs (x : ℝ) : dist x 0 = |x|
by simp [Real.dist_eq]
theorem
Real.dist_0_eq_abs
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.dist_eq" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.sub_le_dist (x y : ℝ) : x - y ≤ dist x y
by rw [Real.dist_eq, le_abs] exact Or.inl (le_refl _)
theorem
Real.sub_le_dist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.dist_eq", "le_refl" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.ball_eq_Ioo (x r : ℝ) : ball x r = Ioo (x - r) (x + r)
Set.ext fun y => by rw [mem_ball, dist_comm, Real.dist_eq, abs_sub_lt_iff, mem_Ioo, ← sub_lt_iff_lt_add', sub_lt_comm]
theorem
Real.ball_eq_Ioo
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.dist_eq", "Set.ext", "dist_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.ball_zero_eq_Ioo (r : ℝ) : ball 0 r = Ioo (-r) r
by simp [Real.ball_eq_Ioo]
theorem
Real.ball_zero_eq_Ioo
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.ball_eq_Ioo" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.closedBall_eq_Icc {x r : ℝ} : closedBall x r = Icc (x - r) (x + r)
by ext y rw [mem_closedBall, dist_comm, Real.dist_eq, abs_sub_le_iff, mem_Icc, ← sub_le_iff_le_add', sub_le_comm]
theorem
Real.closedBall_eq_Icc
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.dist_eq", "dist_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.closedBall_zero_eq_Icc (r : ℝ) : closedBall 0 r = Icc (-r) r
by simp [Real.closedBall_eq_Icc]
theorem
Real.closedBall_zero_eq_Icc
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.closedBall_eq_Icc" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.Ioo_eq_ball (x y : ℝ) : Ioo x y = ball ((x + y) / 2) ((y - x) / 2)
by rw [Real.ball_eq_Ioo, ← sub_div, add_comm, ← sub_add, add_sub_cancel_left, add_self_div_two, ← add_div, add_assoc, add_sub_cancel, add_self_div_two]
theorem
Real.Ioo_eq_ball
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.ball_eq_Ioo", "add_div", "add_self_div_two", "sub_div" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.Icc_eq_closedBall (x y : ℝ) : Icc x y = closedBall ((x + y) / 2) ((y - x) / 2)
by rw [Real.closedBall_eq_Icc, ← sub_div, add_comm, ← sub_add, add_sub_cancel_left, add_self_div_two, ← add_div, add_assoc, add_sub_cancel, add_self_div_two]
theorem
Real.Icc_eq_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.closedBall_eq_Icc", "add_div", "add_self_div_two", "sub_div" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.sphere_eq_pair (x : ℝ) {r : ℝ} (hr : 0 ≤ r) : sphere x r = {x - r, x + r}
by ext; simp [dist_eq]; grind
lemma
Real.sphere_eq_pair
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.uniformity_eq_comap_nhds_zero : 𝓤 α = comap (fun p : α × α => dist p.1 p.2) (𝓝 (0 : ℝ))
by ext s simp only [mem_uniformity_dist, (nhds_basis_ball.comap _).mem_iff] simp [subset_def, Real.dist_0_eq_abs]
theorem
Metric.uniformity_eq_comap_nhds_zero
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Real.dist_0_eq_abs", "comap" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_uniformity_iff_dist_tendsto_zero {f : ι → α × α} {p : Filter ι} : Tendsto f p (𝓤 α) ↔ Tendsto (fun x => dist (f x).1 (f x).2) p (𝓝 0)
by rw [Metric.uniformity_eq_comap_nhds_zero, tendsto_comap_iff, Function.comp_def]
theorem
tendsto_uniformity_iff_dist_tendsto_zero
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Filter", "Metric.uniformity_eq_comap_nhds_zero" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Filter.Tendsto.congr_dist {f₁ f₂ : ι → α} {p : Filter ι} {a : α} (h₁ : Tendsto f₁ p (𝓝 a)) (h : Tendsto (fun x => dist (f₁ x) (f₂ x)) p (𝓝 0)) : Tendsto f₂ p (𝓝 a)
h₁.congr_uniformity <| tendsto_uniformity_iff_dist_tendsto_zero.2 h alias tendsto_of_tendsto_of_dist := Filter.Tendsto.congr_dist
theorem
Filter.Tendsto.congr_dist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Filter", "f₁", "f₂" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_iff_of_dist {f₁ f₂ : ι → α} {p : Filter ι} {a : α} (h : Tendsto (fun x => dist (f₁ x) (f₂ x)) p (𝓝 0)) : Tendsto f₁ p (𝓝 a) ↔ Tendsto f₂ p (𝓝 a)
Uniform.tendsto_congr <| tendsto_uniformity_iff_dist_tendsto_zero.2 h
theorem
tendsto_iff_of_dist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Filter", "Uniform.tendsto_congr", "f₁", "f₂" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
PseudoMetricSpace.dist_eq_of_dist_zero (x : α) {y z : α} (h : dist y z = 0) : dist x y = dist x z
dist_comm y x ▸ dist_comm z x ▸ sub_eq_zero.1 (abs_nonpos_iff.1 (h ▸ abs_dist_sub_le y z x))
theorem
PseudoMetricSpace.dist_eq_of_dist_zero
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "abs_dist_sub_le", "dist_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_dist_dist_le_left (x y z : α) : dist (dist x z) (dist y z) ≤ dist x y
abs_dist_sub_le ..
theorem
dist_dist_dist_le_left
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "abs_dist_sub_le" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_dist_dist_le_right (x y z : α) : dist (dist x y) (dist x z) ≤ dist y z
by simpa only [dist_comm x] using dist_dist_dist_le_left y z x
theorem
dist_dist_dist_le_right
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "dist_comm", "dist_dist_dist_le_left" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_dist_dist_le (x y x' y' : α) : dist (dist x y) (dist x' y') ≤ dist x x' + dist y y'
(dist_triangle _ _ _).trans <| add_le_add (dist_dist_dist_le_left _ _ _) (dist_dist_dist_le_right _ _ _)
theorem
dist_dist_dist_le
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "dist_dist_dist_le_left", "dist_dist_dist_le_right", "dist_triangle", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nhds_comap_dist (a : α) : ((𝓝 (0 : ℝ)).comap (dist · a)) = 𝓝 a
by simp only [@nhds_eq_comap_uniformity α, Metric.uniformity_eq_comap_nhds_zero, comap_comap, Function.comp_def, dist_comm]
theorem
nhds_comap_dist
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Metric.uniformity_eq_comap_nhds_zero", "comap", "dist_comm", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_iff_dist_tendsto_zero {f : β → α} {x : Filter β} {a : α} : Tendsto f x (𝓝 a) ↔ Tendsto (fun b => dist (f b) a) x (𝓝 0)
by rw [← nhds_comap_dist a, tendsto_comap_iff, Function.comp_def]
theorem
tendsto_iff_dist_tendsto_zero
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Filter", "nhds_comap_dist" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ball_subset_interior_closedBall : ball x ε ⊆ interior (closedBall x ε)
interior_maximal ball_subset_closedBall isOpen_ball
theorem
Metric.ball_subset_interior_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "interior", "interior_maximal" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_closure_iff {s : Set α} {a : α} : a ∈ closure s ↔ ∀ ε > 0, ∃ b ∈ s, dist a b < ε
(mem_closure_iff_nhds_basis nhds_basis_ball).trans <| by simp only [mem_ball, dist_comm]
theorem
Metric.mem_closure_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Set", "closure", "dist_comm", "mem_closure_iff", "mem_closure_iff_nhds_basis", "trans" ]
ε-characterization of the closure in pseudometric spaces
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_closure_range_iff {e : β → α} {a : α} : a ∈ closure (range e) ↔ ∀ ε > 0, ∃ k : β, dist a (e k) < ε
by simp only [mem_closure_iff, exists_range_iff]
theorem
Metric.mem_closure_range_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "closure", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_closure_range_iff_nat {e : β → α} {a : α} : a ∈ closure (range e) ↔ ∀ n : ℕ, ∃ k : β, dist a (e k) < 1 / ((n : ℝ) + 1)
(mem_closure_iff_nhds_basis nhds_basis_ball_inv_nat_succ).trans <| by simp only [mem_ball, dist_comm, exists_range_iff, forall_const]
theorem
Metric.mem_closure_range_iff_nat
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "closure", "dist_comm", "mem_closure_iff_nhds_basis", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_of_closed' {s : Set α} (hs : IsClosed s) {a : α} : a ∈ s ↔ ∀ ε > 0, ∃ b ∈ s, dist a b < ε
by simpa only [hs.closure_eq] using @mem_closure_iff _ _ s a
theorem
Metric.mem_of_closed'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "IsClosed", "Set", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dense_iff {s : Set α} : Dense s ↔ ∀ x, ∀ r > 0, (ball x r ∩ s).Nonempty
forall_congr' fun x => by simp only [mem_closure_iff, Set.Nonempty, mem_inter_iff, mem_ball', and_comm]
theorem
Metric.dense_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Dense", "Set", "Set.Nonempty", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dense_iff_iUnion_ball (s : Set α) : Dense s ↔ ∀ r > 0, ⋃ c ∈ s, ball c r = univ
by simp_rw [eq_univ_iff_forall, mem_iUnion, exists_prop, mem_ball, Dense, mem_closure_iff, forall_comm (α := α)]
theorem
Metric.dense_iff_iUnion_ball
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Dense", "Set", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
denseRange_iff {f : β → α} : DenseRange f ↔ ∀ x, ∀ r > 0, ∃ y, dist x (f y) < r
forall_congr' fun x => by simp only [mem_closure_iff, exists_range_iff]
theorem
Metric.denseRange_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "DenseRange", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_ofMul (a b : X) : nndist (ofMul a) (ofMul b) = nndist a b
rfl
theorem
nndist_ofMul
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_ofAdd (a b : X) : nndist (ofAdd a) (ofAdd b) = nndist a b
rfl
theorem
nndist_ofAdd
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_toMul (a b : Additive X) : nndist a.toMul b.toMul = nndist a b
rfl
theorem
nndist_toMul
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Additive" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_toAdd (a b : Multiplicative X) : nndist a.toAdd b.toAdd = nndist a b
rfl
theorem
nndist_toAdd
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[ "Multiplicative" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_toDual (a b : X) : nndist (toDual a) (toDual b) = nndist a b
rfl
theorem
nndist_toDual
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_ofDual (a b : Xᵒᵈ) : nndist (ofDual a) (ofDual b) = nndist a b
rfl
theorem
nndist_ofDual
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Defs.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Real.singleton_eq_inter_Icc (b : ℝ) : {b} = ⋂ (r > 0), Icc (b - r) (b + r)
by simp [Icc_eq_closedBall, biInter_basis_nhds Metric.nhds_basis_closedBall]
lemma
Real.singleton_eq_inter_Icc
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "Metric.nhds_basis_closedBall", "biInter_basis_nhds" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
squeeze_zero' {α} {f g : α → ℝ} {t₀ : Filter α} (hf : ∀ᶠ t in t₀, 0 ≤ f t) (hft : ∀ᶠ t in t₀, f t ≤ g t) (g0 : Tendsto g t₀ (𝓝 0)) : Tendsto f t₀ (𝓝 0)
tendsto_of_tendsto_of_tendsto_of_le_of_le' tendsto_const_nhds g0 hf hft
lemma
squeeze_zero'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "Filter", "tendsto_const_nhds", "tendsto_of_tendsto_of_tendsto_of_le_of_le'" ]
Special case of the sandwich lemma; see `tendsto_of_tendsto_of_tendsto_of_le_of_le'` for the general case.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
squeeze_zero {α} {f g : α → ℝ} {t₀ : Filter α} (hf : ∀ t, 0 ≤ f t) (hft : ∀ t, f t ≤ g t) (g0 : Tendsto g t₀ (𝓝 0)) : Tendsto f t₀ (𝓝 0)
squeeze_zero' (Eventually.of_forall hf) (Eventually.of_forall hft) g0
lemma
squeeze_zero
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "Filter", "squeeze_zero'" ]
Special case of the sandwich lemma; see `tendsto_of_tendsto_of_tendsto_of_le_of_le` and `tendsto_of_tendsto_of_tendsto_of_le_of_le'` for the general case.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eventually_closedBall_subset {x : α} {u : Set α} (hu : u ∈ 𝓝 x) : ∀ᶠ r in 𝓝 (0 : ℝ), closedBall x r ⊆ u
by obtain ⟨ε, εpos, hε⟩ : ∃ ε, 0 < ε ∧ closedBall x ε ⊆ u := nhds_basis_closedBall.mem_iff.1 hu have : Iic ε ∈ 𝓝 (0 : ℝ) := Iic_mem_nhds εpos filter_upwards [this] with _ hr using Subset.trans (closedBall_subset_closedBall hr) hε
lemma
eventually_closedBall_subset
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "Set" ]
If `u` is a neighborhood of `x`, then for small enough `r`, the closed ball `Metric.closedBall x r` is contained in `u`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_closedBall_smallSets (x : α) : Tendsto (closedBall x) (𝓝 0) (𝓝 x).smallSets
tendsto_smallSets_iff.2 fun _ ↦ eventually_closedBall_subset
lemma
tendsto_closedBall_smallSets
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "eventually_closedBall_subset" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eventually_ball_subset {x : α} {u : Set α} (hu : u ∈ 𝓝 x) : ∀ᶠ r in 𝓝 (0 : ℝ), ball x r ⊆ u
(eventually_closedBall_subset hu).mono fun _r hr ↦ ball_subset_closedBall.trans hr
lemma
eventually_ball_subset
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "Set", "eventually_closedBall_subset" ]
If `u` is a neighborhood of `x`, then for small enough `r`, the open ball `Metric.ball x r` is contained in `u`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isClosed_closedBall : IsClosed (closedBall x ε)
isClosed_le (by fun_prop) continuous_const
lemma
Metric.isClosed_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "IsClosed", "continuous_const", "isClosed_le" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isClosed_sphere : IsClosed (sphere x ε)
isClosed_eq (by fun_prop) continuous_const
lemma
Metric.isClosed_sphere
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "IsClosed", "continuous_const", "isClosed_eq" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
closure_closedBall : closure (closedBall x ε) = closedBall x ε
isClosed_closedBall.closure_eq
lemma
Metric.closure_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "closure" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
closure_sphere : closure (sphere x ε) = sphere x ε
isClosed_sphere.closure_eq
lemma
Metric.closure_sphere
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "closure" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
closure_ball_subset_closedBall : closure (ball x ε) ⊆ closedBall x ε
closure_minimal ball_subset_closedBall isClosed_closedBall
lemma
Metric.closure_ball_subset_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "closure", "closure_minimal" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
frontier_ball_subset_sphere : frontier (ball x ε) ⊆ sphere x ε
frontier_lt_subset_eq (by fun_prop) continuous_const
lemma
Metric.frontier_ball_subset_sphere
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "continuous_const", "frontier", "frontier_lt_subset_eq" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
frontier_closedBall_subset_sphere : frontier (closedBall x ε) ⊆ sphere x ε
frontier_le_subset_eq (by fun_prop) continuous_const
lemma
Metric.frontier_closedBall_subset_sphere
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "continuous_const", "frontier", "frontier_le_subset_eq" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
closedBall_zero' (x : α) : closedBall x 0 = closure {x}
Subset.antisymm (fun _y hy => mem_closure_iff.2 fun _ε ε0 => ⟨x, mem_singleton x, (mem_closedBall.1 hy).trans_lt ε0⟩) (closure_minimal (singleton_subset_iff.2 (dist_self x).le) isClosed_closedBall)
lemma
Metric.closedBall_zero'
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "closure", "closure_minimal", "dist_self" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eventually_isCompact_closedBall [WeaklyLocallyCompactSpace α] (x : α) : ∀ᶠ r in 𝓝 (0 : ℝ), IsCompact (closedBall x r)
by rcases exists_compact_mem_nhds x with ⟨s, s_compact, hs⟩ filter_upwards [eventually_closedBall_subset hs] with r hr exact IsCompact.of_isClosed_subset s_compact isClosed_closedBall hr
lemma
Metric.eventually_isCompact_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "IsCompact", "IsCompact.of_isClosed_subset", "WeaklyLocallyCompactSpace", "eventually_closedBall_subset" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_isCompact_closedBall [WeaklyLocallyCompactSpace α] (x : α) : ∃ r, 0 < r ∧ IsCompact (closedBall x r)
by have : ∀ᶠ r in 𝓝[>] 0, IsCompact (closedBall x r) := eventually_nhdsWithin_of_eventually_nhds (eventually_isCompact_closedBall x) simpa only [and_comm] using (this.and self_mem_nhdsWithin).exists
lemma
Metric.exists_isCompact_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "IsCompact", "WeaklyLocallyCompactSpace", "eventually_nhdsWithin_of_eventually_nhds", "self_mem_nhdsWithin" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
biInter_gt_closedBall (x : α) (r : ℝ) : ⋂ r' > r, closedBall x r' = closedBall x r
by ext simp [forall_gt_imp_ge_iff_le_of_dense]
theorem
Metric.biInter_gt_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "forall_gt_imp_ge_iff_le_of_dense" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
biInter_gt_ball (x : α) (r : ℝ) : ⋂ r' > r, ball x r' = closedBall x r
by ext simp [forall_gt_iff_le]
theorem
Metric.biInter_gt_ball
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
biUnion_lt_ball (x : α) (r : ℝ) : ⋃ r' < r, ball x r' = ball x r
by ext rw [← not_iff_not] simp [forall_lt_imp_le_iff_le_of_dense]
theorem
Metric.biUnion_lt_ball
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "not_iff_not" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
biUnion_lt_closedBall (x : α) (r : ℝ) : ⋃ r' < r, closedBall x r' = ball x r
by ext rw [← not_iff_not] simp [forall_lt_iff_le]
theorem
Metric.biUnion_lt_closedBall
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "forall_lt_iff_le", "not_iff_not" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
lebesgue_number_lemma_of_metric {s : Set α} {ι : Sort*} {c : ι → Set α} (hs : IsCompact s) (hc₁ : ∀ i, IsOpen (c i)) (hc₂ : s ⊆ ⋃ i, c i) : ∃ δ > 0, ∀ x ∈ s, ∃ i, ball x δ ⊆ c i
by simpa only [ball, UniformSpace.ball, preimage_setOf_eq, dist_comm] using uniformity_basis_dist.lebesgue_number_lemma hs hc₁ hc₂
theorem
lebesgue_number_lemma_of_metric
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "IsCompact", "IsOpen", "Set", "UniformSpace.ball", "dist_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
lebesgue_number_lemma_of_metric_sUnion {s : Set α} {c : Set (Set α)} (hs : IsCompact s) (hc₁ : ∀ t ∈ c, IsOpen t) (hc₂ : s ⊆ ⋃₀ c) : ∃ δ > 0, ∀ x ∈ s, ∃ t ∈ c, ball x δ ⊆ t
by rw [sUnion_eq_iUnion] at hc₂; simpa using lebesgue_number_lemma_of_metric hs (by simpa) hc₂
theorem
lebesgue_number_lemma_of_metric_sUnion
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Lemmas.lean
[]
[ "IsCompact", "IsOpen", "Set", "lebesgue_number_lemma_of_metric" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pseudoMetricSpacePi : PseudoMetricSpace (∀ b, X b)
by /- we construct the instance from the pseudoemetric space instance to avoid checking again that the uniformity is the same as the product uniformity, but we register nevertheless a nice formula for the distance -/ let i := PseudoEMetricSpace.toPseudoMetricSpaceOfDist (fun f g : ∀ b, X b => ((sup univ...
instance
pseudoMetricSpacePi
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[ "Filter.eventually_all", "Finset.mem_univ", "NNReal.zero_le_coe", "PseudoEMetricSpace.toPseudoMetricSpaceOfDist", "PseudoMetricSpace", "dist_nndist", "edist_pi_def" ]
A finite product of pseudometric spaces is a pseudometric space, with the sup distance.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_pi_def (f g : ∀ b, X b) : nndist f g = sup univ fun b => nndist (f b) (g b)
rfl
lemma
nndist_pi_def
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_pi_def (f g : ∀ b, X b) : dist f g = (sup univ fun b => nndist (f b) (g b) : ℝ≥0)
rfl
lemma
dist_pi_def
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_pi_le_iff {f g : ∀ b, X b} {r : ℝ≥0} : nndist f g ≤ r ↔ ∀ b, nndist (f b) (g b) ≤ r
by simp [nndist_pi_def]
lemma
nndist_pi_le_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[ "nndist_pi_def" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_pi_lt_iff {f g : ∀ b, X b} {r : ℝ≥0} (hr : 0 < r) : nndist f g < r ↔ ∀ b, nndist (f b) (g b) < r
by simp [nndist_pi_def, Finset.sup_lt_iff hr]
lemma
nndist_pi_lt_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[ "Finset.sup_lt_iff", "nndist_pi_def" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_pi_eq_iff {f g : ∀ b, X b} {r : ℝ≥0} (hr : 0 < r) : nndist f g = r ↔ (∃ i, nndist (f i) (g i) = r) ∧ ∀ b, nndist (f b) (g b) ≤ r
by rw [eq_iff_le_not_lt, nndist_pi_lt_iff hr, nndist_pi_le_iff, not_forall, and_comm] simp_rw [not_lt, and_congr_left_iff, le_antisymm_iff] intro h refine exists_congr fun b => ?_ apply (and_iff_right <| h _).symm
lemma
nndist_pi_eq_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[ "eq_iff_le_not_lt", "le_antisymm_iff", "nndist_pi_le_iff", "nndist_pi_lt_iff", "not_lt", "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_pi_lt_iff {f g : ∀ b, X b} {r : ℝ} (hr : 0 < r) : dist f g < r ↔ ∀ b, dist (f b) (g b) < r
by lift r to ℝ≥0 using hr.le exact nndist_pi_lt_iff hr
lemma
dist_pi_lt_iff
Topology.MetricSpace.Pseudo
Mathlib/Topology/MetricSpace/Pseudo/Pi.lean
[]
[ "nndist_pi_lt_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319