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le_add_mul {f : α → ℝ} {K : ℝ≥0} (h : LipschitzWith K f) (x y) : f x ≤ f y + K * dist x y
sub_le_iff_le_add'.1 <| le_trans (le_abs_self _) <| h.dist_le_mul x y
theorem
LipschitzWith.le_add_mul
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "le_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iff_le_add_mul {f : α → ℝ} {K : ℝ≥0} : LipschitzWith K f ↔ ∀ x y, f x ≤ f y + K * dist x y
⟨LipschitzWith.le_add_mul, LipschitzWith.of_le_add_mul K⟩
theorem
LipschitzWith.iff_le_add_mul
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.of_le_add_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
nndist_le (hf : LipschitzWith K f) (x y : α) : nndist (f x) (f y) ≤ K * nndist x y
hf.dist_le_mul x y
theorem
LipschitzWith.nndist_le
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_le_mul_of_le (hf : LipschitzWith K f) (hr : dist x y ≤ r) : dist (f x) (f y) ≤ K * r
(hf.dist_le_mul x y).trans <| by gcongr
theorem
LipschitzWith.dist_le_mul_of_le
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mapsTo_closedBall (hf : LipschitzWith K f) (x : α) (r : ℝ) : MapsTo f (Metric.closedBall x r) (Metric.closedBall (f x) (K * r))
fun _y hy => hf.dist_le_mul_of_le hy
theorem
LipschitzWith.mapsTo_closedBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "Metric.closedBall" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_lt_mul_of_lt (hf : LipschitzWith K f) (hK : K ≠ 0) (hr : dist x y < r) : dist (f x) (f y) < K * r
(hf.dist_le_mul x y).trans_lt <| by gcongr
theorem
LipschitzWith.dist_lt_mul_of_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mapsTo_ball (hf : LipschitzWith K f) (hK : K ≠ 0) (x : α) (r : ℝ) : MapsTo f (Metric.ball x r) (Metric.ball (f x) (K * r))
fun _y hy => hf.dist_lt_mul_of_lt hK hy
theorem
LipschitzWith.mapsTo_ball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "Metric.ball" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toLocallyBoundedMap (f : α → β) (hf : LipschitzWith K f) : LocallyBoundedMap α β
LocallyBoundedMap.ofMapBounded f fun _s hs => let ⟨C, hC⟩ := Metric.isBounded_iff.1 hs Metric.isBounded_iff.2 ⟨K * C, forall_mem_image.2 fun _x hx => forall_mem_image.2 fun _y hy => hf.dist_le_mul_of_le (hC hx hy)⟩
def
LipschitzWith.toLocallyBoundedMap
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LocallyBoundedMap", "LocallyBoundedMap.ofMapBounded" ]
A Lipschitz continuous map is a locally bounded map.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
coe_toLocallyBoundedMap (hf : LipschitzWith K f) : ⇑(hf.toLocallyBoundedMap f) = f
rfl
theorem
LipschitzWith.coe_toLocallyBoundedMap
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comap_cobounded_le (hf : LipschitzWith K f) : comap f (Bornology.cobounded β) ≤ Bornology.cobounded α
(hf.toLocallyBoundedMap f).2
theorem
LipschitzWith.comap_cobounded_le
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "comap" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBounded_image (hf : LipschitzWith K f) {s : Set α} (hs : IsBounded s) : IsBounded (f '' s)
hs.image (toLocallyBoundedMap f hf)
theorem
LipschitzWith.isBounded_image
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "Set" ]
The image of a bounded set under a Lipschitz map is bounded.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
diam_image_le (hf : LipschitzWith K f) (s : Set α) (hs : IsBounded s) : Metric.diam (f '' s) ≤ K * Metric.diam s
Metric.diam_le_of_forall_dist_le (mul_nonneg K.coe_nonneg Metric.diam_nonneg) <| forall_mem_image.2 fun _x hx => forall_mem_image.2 fun _y hy => hf.dist_le_mul_of_le <| Metric.dist_le_diam_of_mem hs hx hy
theorem
LipschitzWith.diam_image_le
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "Metric.diam", "Metric.diam_le_of_forall_dist_le", "Metric.diam_nonneg", "Metric.dist_le_diam_of_mem", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_left (y : α) : LipschitzWith 1 (dist · y)
LipschitzWith.mk_one fun _ _ => dist_dist_dist_le_left _ _ _
theorem
LipschitzWith.dist_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.mk_one", "dist_dist_dist_le_left" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_right (x : α) : LipschitzWith 1 (dist x)
LipschitzWith.of_le_add fun _ _ => dist_triangle_right _ _ _
theorem
LipschitzWith.dist_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.of_le_add", "dist_triangle_right" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist : LipschitzWith 2 (Function.uncurry <| @dist α _)
by rw [← one_add_one_eq_two] exact LipschitzWith.uncurry LipschitzWith.dist_left LipschitzWith.dist_right
theorem
LipschitzWith.dist
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.dist_left", "LipschitzWith.dist_right", "LipschitzWith.uncurry", "one_add_one_eq_two" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_iterate_succ_le_geometric {f : α → α} (hf : LipschitzWith K f) (x n) : dist (f^[n] x) (f^[n + 1] x) ≤ dist x (f x) * (K : ℝ) ^ n
by rw [iterate_succ, mul_comm] simpa only [NNReal.coe_pow] using! (hf.iterate n).dist_le_mul x (f x)
theorem
LipschitzWith.dist_iterate_succ_le_geometric
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "NNReal.coe_pow", "mul_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.lipschitzWith_max : LipschitzWith 1 fun p : ℝ × ℝ => max p.1 p.2
LipschitzWith.of_le_add fun _ _ => sub_le_iff_le_add'.1 <| (le_abs_self _).trans (abs_max_sub_max_le_max _ _ _ _)
theorem
lipschitzWith_max
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.of_le_add", "abs_max_sub_max_le_max", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.lipschitzWith_min : LipschitzWith 1 fun p : ℝ × ℝ => min p.1 p.2
LipschitzWith.of_le_add fun _ _ => sub_le_iff_le_add'.1 <| (le_abs_self _).trans (abs_min_sub_min_le_max _ _ _ _)
theorem
lipschitzWith_min
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.of_le_add", "abs_min_sub_min_le_max", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.Real.lipschitzWith_toNNReal : LipschitzWith 1 Real.toNNReal
by refine lipschitzWith_iff_dist_le_mul.mpr (fun x y ↦ ?_) simpa only [NNReal.coe_one, dist_prod_same_right, one_mul, Real.dist_eq] using! lipschitzWith_iff_dist_le_mul.mp lipschitzWith_max (x, 0) (y, 0)
lemma
Real.lipschitzWith_toNNReal
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "NNReal.coe_one", "Real.dist_eq", "Real.toNNReal", "dist_prod_same_right", "lipschitzWith_max", "one_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
max (hf : LipschitzWith Kf f) (hg : LipschitzWith Kg g) : LipschitzWith (max Kf Kg) fun x => max (f x) (g x)
by simpa only [(· ∘ ·), one_mul] using! lipschitzWith_max.comp (hf.prodMk hg)
theorem
LipschitzWith.max
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "one_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
min (hf : LipschitzWith Kf f) (hg : LipschitzWith Kg g) : LipschitzWith (max Kf Kg) fun x => min (f x) (g x)
by simpa only [(· ∘ ·), one_mul] using! lipschitzWith_min.comp (hf.prodMk hg)
theorem
LipschitzWith.min
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "one_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
max_const (hf : LipschitzWith Kf f) (a : ℝ) : LipschitzWith Kf fun x => max (f x) a
by simpa using hf.max (LipschitzWith.const a)
theorem
LipschitzWith.max_const
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.const" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
const_max (hf : LipschitzWith Kf f) (a : ℝ) : LipschitzWith Kf fun x => max a (f x)
by simpa only [max_comm] using hf.max_const a
theorem
LipschitzWith.const_max
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
min_const (hf : LipschitzWith Kf f) (a : ℝ) : LipschitzWith Kf fun x => min (f x) a
by simpa using hf.min (LipschitzWith.const a)
theorem
LipschitzWith.min_const
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "LipschitzWith.const" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
const_min (hf : LipschitzWith Kf f) (a : ℝ) : LipschitzWith Kf fun x => min a (f x)
by simpa only [min_comm] using hf.min_const a
theorem
LipschitzWith.const_min
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith", "min_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
projIcc {a b : ℝ} (h : a ≤ b) : LipschitzWith 1 (projIcc a b h)
((LipschitzWith.id.const_min _).const_max _).subtype_mk _
theorem
LipschitzWith.projIcc
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzWith" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
LipschitzWith.properSpace {X Y : Type*} [PseudoMetricSpace X] [PseudoMetricSpace Y] [ProperSpace Y] {f : X → Y} (hf : IsProperMap f) {K : ℝ≥0} (hf' : LipschitzWith K f) : ProperSpace X
⟨fun x r ↦ (hf.isCompact_preimage (isCompact_closedBall (f x) (K * r))).of_isClosed_subset Metric.isClosed_closedBall (hf'.mapsTo_closedBall x r).subset_preimage⟩
lemma
LipschitzWith.properSpace
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "IsProperMap", "LipschitzWith", "Metric.isClosed_closedBall", "ProperSpace", "PseudoMetricSpace" ]
The preimage of a proper space under a Lipschitz proper map is proper.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
of_dist_le' {K : ℝ} (h : ∀ x ∈ s, ∀ y ∈ s, dist (f x) (f y) ≤ K * dist x y) : LipschitzOnWith (Real.toNNReal K) f s
of_dist_le_mul fun x hx y hy => le_trans (h x hx y hy) <| by gcongr; apply Real.le_coe_toNNReal
theorem
LipschitzOnWith.of_dist_le'
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "Real.le_coe_toNNReal", "Real.toNNReal", "le_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk_one (h : ∀ x ∈ s, ∀ y ∈ s, dist (f x) (f y) ≤ dist x y) : LipschitzOnWith 1 f s
of_dist_le_mul <| by simpa only [NNReal.coe_one, one_mul] using h
theorem
LipschitzOnWith.mk_one
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "NNReal.coe_one", "one_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
of_le_add_mul' {f : α → ℝ} (K : ℝ) (h : ∀ x ∈ s, ∀ y ∈ s, f x ≤ f y + K * dist x y) : LipschitzOnWith (Real.toNNReal K) f s
have I : ∀ x ∈ s, ∀ y ∈ s, f x - f y ≤ K * dist x y := fun x hx y hy => sub_le_iff_le_add'.2 (h x hx y hy) LipschitzOnWith.of_dist_le' fun x hx y hy => abs_sub_le_iff.2 ⟨I x hx y hy, dist_comm y x ▸ I y hy x hx⟩
theorem
LipschitzOnWith.of_le_add_mul'
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "LipschitzOnWith.of_dist_le'", "Real.toNNReal", "dist_comm" ]
For functions to `ℝ`, it suffices to prove `f x ≤ f y + K * dist x y`; this version doesn't assume `0≤K`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
of_le_add_mul {f : α → ℝ} (K : ℝ≥0) (h : ∀ x ∈ s, ∀ y ∈ s, f x ≤ f y + K * dist x y) : LipschitzOnWith K f s
by simpa only [Real.toNNReal_coe] using LipschitzOnWith.of_le_add_mul' K h
theorem
LipschitzOnWith.of_le_add_mul
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "LipschitzOnWith.of_le_add_mul'", "Real.toNNReal_coe" ]
For functions to `ℝ`, it suffices to prove `f x ≤ f y + K * dist x y`; this version assumes `0≤K`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
of_le_add {f : α → ℝ} (h : ∀ x ∈ s, ∀ y ∈ s, f x ≤ f y + dist x y) : LipschitzOnWith 1 f s
LipschitzOnWith.of_le_add_mul 1 <| by simpa only [NNReal.coe_one, one_mul]
theorem
LipschitzOnWith.of_le_add
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "LipschitzOnWith.of_le_add_mul", "NNReal.coe_one", "one_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
le_add_mul {f : α → ℝ} {K : ℝ≥0} (h : LipschitzOnWith K f s) {x : α} (hx : x ∈ s) {y : α} (hy : y ∈ s) : f x ≤ f y + K * dist x y
sub_le_iff_le_add'.1 <| le_trans (le_abs_self _) <| h.dist_le_mul x hx y hy
theorem
LipschitzOnWith.le_add_mul
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "le_trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
iff_le_add_mul {f : α → ℝ} {K : ℝ≥0} : LipschitzOnWith K f s ↔ ∀ x ∈ s, ∀ y ∈ s, f x ≤ f y + K * dist x y
⟨LipschitzOnWith.le_add_mul, LipschitzOnWith.of_le_add_mul K⟩
theorem
LipschitzOnWith.iff_le_add_mul
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "LipschitzOnWith.of_le_add_mul" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBounded_image2 (f : α → β → γ) {K₁ K₂ : ℝ≥0} {s : Set α} {t : Set β} (hs : Bornology.IsBounded s) (ht : Bornology.IsBounded t) (hf₁ : ∀ b ∈ t, LipschitzOnWith K₁ (fun a => f a b) s) (hf₂ : ∀ a ∈ s, LipschitzOnWith K₂ (f a) t) : Bornology.IsBounded (Set.image2 f s t)
Metric.isBounded_iff_ediam_ne_top.2 <| ne_top_of_le_ne_top (ENNReal.add_ne_top.mpr ⟨ENNReal.mul_ne_top ENNReal.coe_ne_top hs.ediam_ne_top, ENNReal.mul_ne_top ENNReal.coe_ne_top ht.ediam_ne_top⟩) (ediam_image2_le _ _ _ hf₁ hf₂)
theorem
LipschitzOnWith.isBounded_image2
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "Bornology.IsBounded", "ENNReal.coe_ne_top", "ENNReal.mul_ne_top", "LipschitzOnWith", "Set", "Set.image2", "ne_top_of_le_ne_top" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
min (hf : LocallyLipschitz f) (hg : LocallyLipschitz g) : LocallyLipschitz (fun x => min (f x) (g x))
lipschitzWith_min.locallyLipschitz.comp (hf.prodMk hg)
lemma
LocallyLipschitz.min
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LocallyLipschitz" ]
The minimum of locally Lipschitz functions is locally Lipschitz.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
max (hf : LocallyLipschitz f) (hg : LocallyLipschitz g) : LocallyLipschitz (fun x => max (f x) (g x))
lipschitzWith_max.locallyLipschitz.comp (hf.prodMk hg)
lemma
LocallyLipschitz.max
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LocallyLipschitz" ]
The maximum of locally Lipschitz functions is locally Lipschitz.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
max_const (hf : LocallyLipschitz f) (a : ℝ) : LocallyLipschitz fun x => max (f x) a
hf.max (LocallyLipschitz.const a)
theorem
LocallyLipschitz.max_const
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LocallyLipschitz", "LocallyLipschitz.const" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
const_max (hf : LocallyLipschitz f) (a : ℝ) : LocallyLipschitz fun x => max a (f x)
by simpa [max_comm] using (hf.max_const a)
theorem
LocallyLipschitz.const_max
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LocallyLipschitz" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
min_const (hf : LocallyLipschitz f) (a : ℝ) : LocallyLipschitz fun x => min (f x) a
hf.min (LocallyLipschitz.const a)
theorem
LocallyLipschitz.min_const
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LocallyLipschitz", "LocallyLipschitz.const" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
const_min (hf : LocallyLipschitz f) (a : ℝ) : LocallyLipschitz fun x => min a (f x)
by simpa [min_comm] using (hf.min_const a)
theorem
LocallyLipschitz.const_min
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LocallyLipschitz", "min_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
LipschitzOnWith.extend_real {f : α → ℝ} {s : Set α} {K : ℝ≥0} (hf : LipschitzOnWith K f s) : ∃ g : α → ℝ, LipschitzWith K g ∧ EqOn f g s
by /- An extension is given by `g y = Inf {f x + K * dist y x | x ∈ s}`. Taking `x = y`, one has `g y ≤ f y` for `y ∈ s`, and the other inequality holds because `f` is `K`-Lipschitz, so that it cannot counterbalance the growth of `K * dist y x`. One readily checks from the formula that the extended functi...
theorem
LipschitzOnWith.extend_real
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "LipschitzOnWith", "LipschitzWith", "LipschitzWith.const", "LipschitzWith.of_le_add_mul", "Set", "Subtype.coe_mk", "ciInf_le", "dist_self", "dist_triangle", "dist_triangle_left", "le_antisymm", "le_ciInf" ]
A function `f : α → ℝ` which is `K`-Lipschitz on a subset `s` admits a `K`-Lipschitz extension to the whole space.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
LipschitzOnWith.extend_pi [Fintype ι] {f : α → ι → ℝ} {s : Set α} {K : ℝ≥0} (hf : LipschitzOnWith K f s) : ∃ g : α → ι → ℝ, LipschitzWith K g ∧ EqOn f g s
by have : ∀ i, ∃ g : α → ℝ, LipschitzWith K g ∧ EqOn (fun x => f x i) g s := fun i => by have : LipschitzOnWith K (fun x : α => f x i) s := LipschitzOnWith.of_dist_le_mul fun x hx y hy => (dist_le_pi_dist _ _ i).trans (hf.dist_le_mul x hx y hy) exact this.extend_real choose g hg using this r...
theorem
LipschitzOnWith.extend_pi
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Lipschitz.lean
[]
[ "Fintype", "LipschitzOnWith", "LipschitzWith", "Set", "dist_le_pi_dist", "dist_nonneg", "dist_pi_le_iff", "trans" ]
A function `f : α → (ι → ℝ)` which is `K`-Lipschitz on a subset `s` admits a `K`-Lipschitz extension to the whole space. The same result for the space `ℓ^∞ (ι, ℝ)` over a possibly infinite type `ι` is implemented in `LipschitzOnWith.extend_lp_infty`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated (ε : ℝ≥0∞) (s : Set X) : Prop
s.Pairwise (ε < edist · ·)
def
Metric.IsSeparated
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set" ]
A set `s` is `ε`-separated if the extended distance between any two distinct elements is strictly greater than `ε`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSeparated_iff_setRelIsSeparated : IsSeparated ε s ↔ SetRel.IsSeparated {(x, y) | edist x y ≤ ε} s
by simp [IsSeparated, SetRel.IsSeparated]
lemma
Metric.isSeparated_iff_setRelIsSeparated
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "SetRel.IsSeparated" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.empty : IsSeparated ε (∅ : Set X)
pairwise_empty _
lemma
Metric.IsSeparated.empty
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.singleton : IsSeparated ε {x}
pairwise_singleton ..
lemma
Metric.IsSeparated.singleton
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.of_subsingleton (hs : s.Subsingleton) : IsSeparated ε s
hs.pairwise _ alias _root_.Set.Subsingleton.isSeparated := IsSeparated.of_subsingleton
lemma
Metric.IsSeparated.of_subsingleton
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.anti (hεδ : ε ≤ δ) (hs : IsSeparated δ s) : IsSeparated ε s
hs.mono' fun _ _ ↦ hεδ.trans_lt
lemma
Metric.IsSeparated.anti
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.subset (hst : s ⊆ t) (hs : IsSeparated ε t) : IsSeparated ε s
hs.mono hst
lemma
Metric.IsSeparated.subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSeparated_insert : IsSeparated ε (insert x s) ↔ IsSeparated ε s ∧ ∀ y ∈ s, x ≠ y → ε < edist x y
pairwise_insert_of_symmetric fun _ _ ↦ by simp [edist_comm]
lemma
Metric.isSeparated_insert
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSeparated_insert_of_notMem (hx : x ∉ s) : IsSeparated ε (insert x s) ↔ IsSeparated ε s ∧ ∀ y ∈ s, ε < edist x y
pairwise_insert_of_symmetric_of_notMem (fun _ _ ↦ by simp [edist_comm]) hx
lemma
Metric.isSeparated_insert_of_notMem
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.insert (hs : IsSeparated ε s) (h : ∀ y ∈ s, x ≠ y → ε < edist x y) : IsSeparated ε (insert x s)
isSeparated_insert.2 ⟨hs, h⟩
lemma
Metric.IsSeparated.insert
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isSeparated_zero {X : Type*} [EMetricSpace X] (s : Set X) : IsSeparated 0 s
by simp [IsSeparated, Set.Pairwise]
lemma
Metric.isSeparated_zero
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "EMetricSpace", "Set", "Set.Pairwise" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsSeparated.image_antilipschitz {ε K₁ : ℝ≥0} {f : X → Y} (hs : IsSeparated ε s) (hf : AntilipschitzWith K₁ f) (hK₁ : 0 < K₁) : IsSeparated ↑(ε / K₁) (f '' s)
by rintro x' ⟨x, hx, rfl⟩ y' ⟨y, hy, rfl⟩ hne have hmul : (↑ε : ℝ≥0∞) < edist (f x) (f y) * ↑K₁ := lt_of_lt_of_le (hs hx hy (by grind)) (by rw [mul_comm]; exact hf x y) exact ENNReal.coe_div hK₁.ne' ▸ ENNReal.div_lt_of_lt_mul hmul
lemma
Metric.IsSeparated.image_antilipschitz
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "AntilipschitzWith", "ENNReal.coe_div", "ENNReal.div_lt_of_lt_mul", "lt_of_lt_of_le", "mul_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
AreSeparated (s t : Set X)
∃ r, r ≠ 0 ∧ ∀ x ∈ s, ∀ y ∈ t, r ≤ edist x y
def
Metric.AreSeparated
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set" ]
Two sets in an (extended) metric space are called *metric separated* if the (extended) distance between `x ∈ s` and `y ∈ t` is bounded from below by a positive constant.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
symm (h : AreSeparated s t) : AreSeparated t s
let ⟨r, r0, hr⟩ := h ⟨r, r0, fun y hy x hx => edist_comm x y ▸ hr x hx y hy⟩
theorem
Metric.AreSeparated.symm
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comm : AreSeparated s t ↔ AreSeparated t s
⟨symm, symm⟩
theorem
Metric.AreSeparated.comm
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
empty_left (s : Set X) : AreSeparated ∅ s
⟨1, one_ne_zero, fun _x => False.elim⟩
theorem
Metric.AreSeparated.empty_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set", "one_ne_zero" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
empty_right (s : Set X) : AreSeparated s ∅
(empty_left s).symm
theorem
Metric.AreSeparated.empty_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set", "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
disjoint (h : AreSeparated s t) : Disjoint s t
let ⟨r, r0, hr⟩ := h Set.disjoint_left.mpr fun x hx1 hx2 => r0 <| by simpa using hr x hx1 x hx2
theorem
Metric.AreSeparated.disjoint
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Disjoint" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
subset_compl_right (h : AreSeparated s t) : s ⊆ tᶜ
fun _ hs ht => h.disjoint.le_bot ⟨hs, ht⟩
theorem
Metric.AreSeparated.subset_compl_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mono {s' t'} (hs : s ⊆ s') (ht : t ⊆ t') : AreSeparated s' t' → AreSeparated s t
fun ⟨r, r0, hr⟩ => ⟨r, r0, fun x hx y hy => hr x (hs hx) y (ht hy)⟩
theorem
Metric.AreSeparated.mono
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mono_left {s'} (h' : AreSeparated s' t) (hs : s ⊆ s') : AreSeparated s t
h'.mono hs Subset.rfl
theorem
Metric.AreSeparated.mono_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mono_right {t'} (h' : AreSeparated s t') (ht : t ⊆ t') : AreSeparated s t
h'.mono Subset.rfl ht
theorem
Metric.AreSeparated.mono_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
union_left {s'} (h : AreSeparated s t) (h' : AreSeparated s' t) : AreSeparated (s ∪ s') t
by rcases h, h' with ⟨⟨r, r0, hr⟩, ⟨r', r0', hr'⟩⟩ refine ⟨min r r', ?_, fun x hx y hy => hx.elim ?_ ?_⟩ · rw [← pos_iff_ne_zero] at r0 r0' ⊢ exact lt_min r0 r0' · exact fun hx => (min_le_left _ _).trans (hr _ hx _ hy) · exact fun hx => (min_le_right _ _).trans (hr' _ hx _ hy)
theorem
Metric.AreSeparated.union_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "lt_min", "min_le_left", "min_le_right", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
union_left_iff {s'} : AreSeparated (s ∪ s') t ↔ AreSeparated s t ∧ AreSeparated s' t
⟨fun h => ⟨h.mono_left subset_union_left, h.mono_left subset_union_right⟩, fun h => h.1.union_left h.2⟩
theorem
Metric.AreSeparated.union_left_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
union_right {t'} (h : AreSeparated s t) (h' : AreSeparated s t') : AreSeparated s (t ∪ t')
(h.symm.union_left h'.symm).symm
theorem
Metric.AreSeparated.union_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
union_right_iff {t'} : AreSeparated s (t ∪ t') ↔ AreSeparated s t ∧ AreSeparated s t'
comm.trans <| union_left_iff.trans <| and_congr comm comm
theorem
Metric.AreSeparated.union_right_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
finite_iUnion_left_iff {ι : Type*} {I : Set ι} (hI : I.Finite) {s : ι → Set X} {t : Set X} : AreSeparated (⋃ i ∈ I, s i) t ↔ ∀ i ∈ I, AreSeparated (s i) t
by induction I, hI using Set.Finite.induction_on with | empty => simp | insert _ _ hI => rw [biUnion_insert, forall_mem_insert, union_left_iff, hI] alias ⟨_, finite_iUnion_left⟩ := finite_iUnion_left_iff
theorem
Metric.AreSeparated.finite_iUnion_left_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set", "Set.Finite.induction_on" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
finite_iUnion_right_iff {ι : Type*} {I : Set ι} (hI : I.Finite) {s : Set X} {t : ι → Set X} : AreSeparated s (⋃ i ∈ I, t i) ↔ ∀ i ∈ I, AreSeparated s (t i)
by simpa only [@comm _ _ s] using finite_iUnion_left_iff hI
theorem
Metric.AreSeparated.finite_iUnion_right_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Set", "comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
finset_iUnion_left_iff {ι : Type*} {I : Finset ι} {s : ι → Set X} {t : Set X} : AreSeparated (⋃ i ∈ I, s i) t ↔ ∀ i ∈ I, AreSeparated (s i) t
finite_iUnion_left_iff I.finite_toSet alias ⟨_, finset_iUnion_left⟩ := finset_iUnion_left_iff
theorem
Metric.AreSeparated.finset_iUnion_left_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Finset", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
finset_iUnion_right_iff {ι : Type*} {I : Finset ι} {s : Set X} {t : ι → Set X} : AreSeparated s (⋃ i ∈ I, t i) ↔ ∀ i ∈ I, AreSeparated s (t i)
finite_iUnion_right_iff I.finite_toSet alias ⟨_, finset_iUnion_right⟩ := finset_iUnion_right_iff
theorem
Metric.AreSeparated.finset_iUnion_right_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/MetricSeparated.lean
[]
[ "Finset", "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
eventually_nhds_zero_forall_closedEBall_subset (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) (x : X) : ∀ᶠ p : ℝ≥0∞ × X in 𝓝 0 ×ˢ 𝓝 x, ∀ i, p.2 ∈ K i → closedEBall p.2 p.1 ⊆ U i
by suffices ∀ i, x ∈ K i → ∀ᶠ p : ℝ≥0∞ × X in 𝓝 0 ×ˢ 𝓝 x, closedEBall p.2 p.1 ⊆ U i by apply mp_mem ((eventually_all_finite (hfin.point_finite x)).2 this) (mp_mem (@tendsto_snd ℝ≥0∞ _ (𝓝 0) _ _ (hfin.iInter_compl_mem_nhds hK x)) _) apply univ_mem' rintro ⟨r, y⟩ hxy hyU i hi simp only [mem_iIn...
theorem
Metric.eventually_nhds_zero_forall_closedEBall_subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "IsClosed", "IsOpen", "LocallyFinite", "add_tsub_cancel_of_le", "le_trans", "lt_trans", "not_imp_not", "tsub_le_tsub_left" ]
Let `K : ι → Set X` be a locally finite family of closed sets in an emetric space. Let `U : ι → Set X` be a family of open sets such that `K i ⊆ U i` for all `i`. Then for any point `x : X`, for sufficiently small `r : ℝ≥0∞` and for `y` sufficiently close to `x`, for all `i`, if `y ∈ K i`, then `Metric.closedEBall y r ...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_forall_closedEBall_subset_aux₁ (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) (x : X) : ∃ r : ℝ, ∀ᶠ y in 𝓝 x, r ∈ Ioi (0 : ℝ) ∩ ENNReal.ofReal ⁻¹' ⋂ (i) (_ : y ∈ K i), { r | closedEBall y r ⊆ U i }
by have := (ENNReal.continuous_ofReal.tendsto' 0 0 ENNReal.ofReal_zero).eventually (eventually_nhds_zero_forall_closedEBall_subset hK hU hKU hfin x).curry rcases this.exists_gt with ⟨r, hr0, hr⟩ refine ⟨r, hr.mono fun y hy => ⟨hr0, ?_⟩⟩ rwa [mem_preimage, mem_iInter₂]
theorem
Metric.exists_forall_closedEBall_subset_aux₁
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "ENNReal.ofReal", "ENNReal.ofReal_zero", "IsClosed", "IsOpen", "LocallyFinite" ]
Auxiliary lemma for `exists_continuous_real_forall_closedEBall_subset` and its smooth counterpart.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_forall_closedEBall_subset_aux₂ (y : X) : Convex ℝ (Ioi (0 : ℝ) ∩ ENNReal.ofReal ⁻¹' ⋂ (i) (_ : y ∈ K i), { r | closedEBall y r ⊆ U i })
(convex_Ioi _).inter <| OrdConnected.convex <| OrdConnected.preimage_ennreal_ofReal <| ordConnected_iInter fun i => ordConnected_iInter fun (_ : y ∈ K i) => ordConnected_setOf_closedEBall_subset y (U i)
theorem
Metric.exists_forall_closedEBall_subset_aux₂
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "Convex", "ENNReal.ofReal", "convex_Ioi" ]
Auxiliary lemma for `exists_continuous_real_forall_closedEBall_subset` and its smooth counterpart.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_continuous_real_forall_closedEBall_subset (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) : ∃ δ : C(X, ℝ), (∀ x, 0 < δ x) ∧ ∀ (i), ∀ x ∈ K i, closedEBall x (ENNReal.ofReal <| δ x) ⊆ U i
by simpa only [mem_inter_iff, forall_and, mem_preimage, mem_iInter, @forall_comm ι X] using! exists_continuous_forall_mem_convex_of_local_const exists_forall_closedEBall_subset_aux₂ (exists_forall_closedEBall_subset_aux₁ hK hU hKU hfin)
theorem
Metric.exists_continuous_real_forall_closedEBall_subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "ENNReal.ofReal", "IsClosed", "IsOpen", "LocallyFinite", "exists_continuous_forall_mem_convex_of_local_const" ]
Let `X` be an extended metric space. Let `K : ι → Set X` be a locally finite family of closed sets, let `U : ι → Set X` be a family of open sets such that `K i ⊆ U i` for all `i`. Then there exists a positive continuous function `δ : C(X, ℝ)` such that for any `i` and `x ∈ K i`, we have `Metric.closedEBall x (ENNReal.o...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_continuous_nnreal_forall_closedEBall_subset (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) : ∃ δ : C(X, ℝ≥0), (∀ x, 0 < δ x) ∧ ∀ (i), ∀ x ∈ K i, closedEBall x (δ x) ⊆ U i
by rcases exists_continuous_real_forall_closedEBall_subset hK hU hKU hfin with ⟨δ, hδ₀, hδ⟩ lift δ to C(X, ℝ≥0) using fun x => (hδ₀ x).le refine ⟨δ, hδ₀, fun i x hi => ?_⟩ simpa only [← ENNReal.ofReal_coe_nnreal] using! hδ i x hi
theorem
Metric.exists_continuous_nnreal_forall_closedEBall_subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "ENNReal.ofReal_coe_nnreal", "IsClosed", "IsOpen", "LocallyFinite" ]
Let `X` be an extended metric space. Let `K : ι → Set X` be a locally finite family of closed sets, let `U : ι → Set X` be a family of open sets such that `K i ⊆ U i` for all `i`. Then there exists a positive continuous function `δ : C(X, ℝ≥0)` such that for any `i` and `x ∈ K i`, we have `Metric.closedEBall x (δ x) ⊆ ...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_continuous_ennreal_forall_closedEBall_subset (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) : ∃ δ : C(X, ℝ≥0∞), (∀ x, 0 < δ x) ∧ ∀ (i), ∀ x ∈ K i, closedEBall x (δ x) ⊆ U i
let ⟨δ, hδ₀, hδ⟩ := exists_continuous_nnreal_forall_closedEBall_subset hK hU hKU hfin ⟨ContinuousMap.comp ⟨Coe.coe, ENNReal.continuous_coe⟩ δ, fun x => ENNReal.coe_pos.2 (hδ₀ x), hδ⟩
theorem
Metric.exists_continuous_ennreal_forall_closedEBall_subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "IsClosed", "IsOpen", "LocallyFinite" ]
Let `X` be an extended metric space. Let `K : ι → Set X` be a locally finite family of closed sets, let `U : ι → Set X` be a family of open sets such that `K i ⊆ U i` for all `i`. Then there exists a positive continuous function `δ : C(X, ℝ≥0∞)` such that for any `i` and `x ∈ K i`, we have `Metric.closedEBall x (δ x) ⊆...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_continuous_nnreal_forall_closedBall_subset (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) : ∃ δ : C(X, ℝ≥0), (∀ x, 0 < δ x) ∧ ∀ (i), ∀ x ∈ K i, closedBall x (δ x) ⊆ U i
by rcases Metric.exists_continuous_nnreal_forall_closedEBall_subset hK hU hKU hfin with ⟨δ, hδ0, hδ⟩ refine ⟨δ, hδ0, fun i x hx => ?_⟩ rw [← Metric.closedEBall_coe] exact hδ i x hx
theorem
Metric.exists_continuous_nnreal_forall_closedBall_subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "IsClosed", "IsOpen", "LocallyFinite", "Metric.closedEBall_coe", "Metric.exists_continuous_nnreal_forall_closedEBall_subset" ]
Let `X` be a metric space. Let `K : ι → Set X` be a locally finite family of closed sets, let `U : ι → Set X` be a family of open sets such that `K i ⊆ U i` for all `i`. Then there exists a positive continuous function `δ : C(X, ℝ≥0)` such that for any `i` and `x ∈ K i`, we have `Metric.closedBall x (δ x) ⊆ U i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_continuous_real_forall_closedBall_subset (hK : ∀ i, IsClosed (K i)) (hU : ∀ i, IsOpen (U i)) (hKU : ∀ i, K i ⊆ U i) (hfin : LocallyFinite K) : ∃ δ : C(X, ℝ), (∀ x, 0 < δ x) ∧ ∀ (i), ∀ x ∈ K i, closedBall x (δ x) ⊆ U i
let ⟨δ, hδ₀, hδ⟩ := exists_continuous_nnreal_forall_closedBall_subset hK hU hKU hfin ⟨ContinuousMap.comp ⟨Coe.coe, NNReal.continuous_coe⟩ δ, hδ₀, hδ⟩
theorem
Metric.exists_continuous_real_forall_closedBall_subset
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PartitionOfUnity.lean
[]
[ "IsClosed", "IsOpen", "LocallyFinite" ]
Let `X` be a metric space. Let `K : ι → Set X` be a locally finite family of closed sets, let `U : ι → Set X` be a family of open sets such that `K i ⊆ U i` for all `i`. Then there exists a positive continuous function `δ : C(X, ℝ)` such that for any `i` and `x ∈ K i`, we have `Metric.closedBall x (δ x) ⊆ U i`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Perfect.small_diam_aux (hC : Perfect C) (ε_pos : 0 < ε) {x : α} (xC : x ∈ C) : let D
closure (Metric.eball x (ε / 2) ∩ C) Perfect D ∧ D.Nonempty ∧ D ⊆ C ∧ Metric.ediam D ≤ ε := by have : x ∈ Metric.eball x (ε / 2) := by apply Metric.mem_eball_self rw [ENNReal.div_pos_iff] exact ⟨ne_of_gt ε_pos, by simp⟩ have := hC.closure_nhds_inter x xC this Metric.isOpen_eball refine ⟨this.1, th...
theorem
Perfect.small_diam_aux
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Perfect.lean
[]
[ "ENNReal.div_mul_cancel", "ENNReal.div_pos_iff", "IsClosed.closure_subset_iff", "Metric.eball", "Metric.ediam", "Metric.ediam_closure", "Metric.ediam_eball_le", "Metric.ediam_mono", "Metric.isOpen_eball", "Metric.mem_eball_self", "Perfect", "closure", "le_trans", "mul_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Perfect.small_diam_splitting (hC : Perfect C) (hnonempty : C.Nonempty) (ε_pos : 0 < ε) : ∃ C₀ C₁ : Set α, (Perfect C₀ ∧ C₀.Nonempty ∧ C₀ ⊆ C ∧ Metric.ediam C₀ ≤ ε) ∧ (Perfect C₁ ∧ C₁.Nonempty ∧ C₁ ⊆ C ∧ Metric.ediam C₁ ≤ ε) ∧ Disjoint C₀ C₁
by rcases hC.splitting hnonempty with ⟨D₀, D₁, ⟨perf0, non0, sub0⟩, ⟨perf1, non1, sub1⟩, hdisj⟩ obtain ⟨x₀, hx₀⟩ := non0 obtain ⟨x₁, hx₁⟩ := non1 rcases perf0.small_diam_aux ε_pos hx₀ with ⟨perf0', non0', sub0', diam0⟩ rcases perf1.small_diam_aux ε_pos hx₁ with ⟨perf1', non1', sub1', diam1⟩ refine ⟨clos...
theorem
Perfect.small_diam_splitting
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Perfect.lean
[]
[ "Disjoint", "Disjoint.mono", "Metric.eball", "Metric.ediam", "Perfect", "Set", "closure" ]
A refinement of `Perfect.splitting` for metric spaces, where we also control the diameter of the new perfect sets.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Perfect.exists_nat_bool_injection (hC : Perfect C) (hnonempty : C.Nonempty) [CompleteSpace α] : ∃ f : (ℕ → Bool) → α, range f ⊆ C ∧ Continuous f ∧ Injective f
by obtain ⟨u, -, upos', hu⟩ := exists_seq_strictAnti_tendsto' (zero_lt_one' ℝ≥0∞) have upos := fun n => (upos' n).1 let P := Subtype fun E : Set α => Perfect E ∧ E.Nonempty choose C0 C1 h0 h1 hdisj using fun {C : Set α} (hC : Perfect C) (hnonempty : C.Nonempty) {ε : ℝ≥0∞} (hε : 0 < ε) => hC.small_diam_s...
theorem
Perfect.exists_nat_bool_injection
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Perfect.lean
[]
[ "CantorScheme.Disjoint", "CompleteSpace", "Continuous", "Perfect", "PiNat.res_length", "Set", "Subtype.val_inj", "exists_seq_strictAnti_tendsto'", "symm", "tendsto_const_nhds", "tendsto_of_tendsto_of_tendsto_of_le_of_le'", "zero_lt_one'" ]
Any nonempty perfect set in a complete metric space admits a continuous injection from the Cantor space, `ℕ → Bool`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
IsClosed.exists_nat_bool_injection_of_not_countable {α : Type*} [TopologicalSpace α] [PolishSpace α] {C : Set α} (hC : IsClosed C) (hunc : ¬C.Countable) : ∃ f : (ℕ → Bool) → α, range f ⊆ C ∧ Continuous f ∧ Function.Injective f
by letI := TopologicalSpace.upgradeIsCompletelyMetrizable α obtain ⟨D, hD, Dnonempty, hDC⟩ := exists_perfect_nonempty_of_isClosed_of_not_countable hC hunc obtain ⟨f, hfD, hf⟩ := hD.exists_nat_bool_injection Dnonempty exact ⟨f, hfD.trans hDC, hf⟩
theorem
IsClosed.exists_nat_bool_injection_of_not_countable
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Perfect.lean
[]
[ "Continuous", "IsClosed", "PolishSpace", "Set", "TopologicalSpace", "TopologicalSpace.upgradeIsCompletelyMetrizable", "exists_perfect_nonempty_of_isClosed_of_not_countable" ]
Any closed uncountable subset of a Polish space admits a continuous injection from the Cantor space `ℕ → Bool`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
apply_firstDiff_ne {x y : ∀ n, E n} (h : x ≠ y) : x (firstDiff x y) ≠ y (firstDiff x y)
by rw [firstDiff_def, dif_pos h] classical exact Nat.find_spec (ne_iff.1 h)
theorem
PiNat.apply_firstDiff_ne
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[ "Nat.find_spec" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
apply_eq_of_lt_firstDiff {x y : ∀ n, E n} {n : ℕ} (hn : n < firstDiff x y) : x n = y n
by rw [firstDiff_def] at hn aesop
theorem
PiNat.apply_eq_of_lt_firstDiff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
firstDiff_comm (x y : ∀ n, E n) : firstDiff x y = firstDiff y x
by classical simp only [firstDiff_def, ne_comm]
theorem
PiNat.firstDiff_comm
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
min_firstDiff_le (x y z : ∀ n, E n) (h : x ≠ z) : min (firstDiff x y) (firstDiff y z) ≤ firstDiff x z
by by_contra! H rw [lt_min_iff] at H refine apply_firstDiff_ne h ?_ calc x (firstDiff x z) = y (firstDiff x z) := apply_eq_of_lt_firstDiff H.1 _ = z (firstDiff x z) := apply_eq_of_lt_firstDiff H.2
theorem
PiNat.min_firstDiff_le
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[ "lt_min_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
cylinder (x : ∀ n, E n) (n : ℕ) : Set (∀ n, E n)
{ y | ∀ i, i < n → y i = x i }
def
PiNat.cylinder
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[ "Set" ]
In a product space `Π n, E n`, the cylinder set of length `n` around `x`, denoted `cylinder x n`, is the set of sequences `y` that coincide with `x` on the first `n` symbols, i.e., such that `y i = x i` for all `i < n`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
cylinder_eq_pi (x : ∀ n, E n) (n : ℕ) : cylinder x n = Set.pi (Finset.range n : Set ℕ) fun i : ℕ => {x i}
by ext y simp [cylinder]
theorem
PiNat.cylinder_eq_pi
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[ "Finset.range", "Set", "Set.pi" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
cylinder_zero (x : ∀ n, E n) : cylinder x 0 = univ
by simp [cylinder_eq_pi]
theorem
PiNat.cylinder_zero
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
cylinder_anti (x : ∀ n, E n) {m n : ℕ} (h : m ≤ n) : cylinder x n ⊆ cylinder x m
fun _y hy i hi => hy i (hi.trans_le h)
theorem
PiNat.cylinder_anti
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_cylinder_iff {x y : ∀ n, E n} {n : ℕ} : y ∈ cylinder x n ↔ ∀ i < n, y i = x i
Iff.rfl
theorem
PiNat.mem_cylinder_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
self_mem_cylinder (x : ∀ n, E n) (n : ℕ) : x ∈ cylinder x n
by simp
theorem
PiNat.self_mem_cylinder
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_cylinder_iff_eq {x y : ∀ n, E n} {n : ℕ} : y ∈ cylinder x n ↔ cylinder y n = cylinder x n
by constructor · intro hy apply Subset.antisymm · intro z hz i hi rw [← hy i hi] exact hz i hi · intro z hz i hi rw [hy i hi] exact hz i hi · intro h rw [← h] exact self_mem_cylinder _ _
theorem
PiNat.mem_cylinder_iff_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_cylinder_comm (x y : ∀ n, E n) (n : ℕ) : y ∈ cylinder x n ↔ x ∈ cylinder y n
by simp [eq_comm]
theorem
PiNat.mem_cylinder_comm
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_cylinder_iff_le_firstDiff {x y : ∀ n, E n} (hne : x ≠ y) (i : ℕ) : x ∈ cylinder y i ↔ i ≤ firstDiff x y
by constructor · intro h by_contra! exact apply_firstDiff_ne hne (h _ this) · intro hi j hj exact apply_eq_of_lt_firstDiff (hj.trans_le hi)
theorem
PiNat.mem_cylinder_iff_le_firstDiff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mem_cylinder_firstDiff (x y : ∀ n, E n) : x ∈ cylinder y (firstDiff x y)
fun _i hi => apply_eq_of_lt_firstDiff hi
theorem
PiNat.mem_cylinder_firstDiff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
cylinder_eq_cylinder_of_le_firstDiff (x y : ∀ n, E n) {n : ℕ} (hn : n ≤ firstDiff x y) : cylinder x n = cylinder y n
by rw [← mem_cylinder_iff_eq] intro i hi exact apply_eq_of_lt_firstDiff (hi.trans_le hn)
theorem
PiNat.cylinder_eq_cylinder_of_le_firstDiff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/PiNat.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319