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ProperSpace (α : Type u) [PseudoMetricSpace α] : Prop where isCompact_closedBall : ∀ x : α, ∀ r, IsCompact (closedBall x r)
class
ProperSpace
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "IsCompact", "PseudoMetricSpace" ]
A pseudometric space is proper if all closed balls are compact.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isCompact_sphere {α : Type*} [PseudoMetricSpace α] [ProperSpace α] (x : α) (r : ℝ) : IsCompact (sphere x r)
(isCompact_closedBall x r).of_isClosed_subset isClosed_sphere sphere_subset_closedBall
theorem
isCompact_sphere
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "IsCompact", "ProperSpace", "PseudoMetricSpace" ]
In a proper pseudometric space, all spheres are compact.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Metric.sphere.compactSpace {α : Type*} [PseudoMetricSpace α] [ProperSpace α] (x : α) (r : ℝ) : CompactSpace (sphere x r)
isCompact_iff_compactSpace.mp (isCompact_sphere _ _)
instance
Metric.sphere.compactSpace
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "CompactSpace", "ProperSpace", "PseudoMetricSpace", "isCompact_sphere" ]
In a proper pseudometric space, any sphere is a `CompactSpace` when considered as a subtype.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ProperSpace.of_isCompact_closedBall_of_le (R : ℝ) (h : ∀ x : α, ∀ r, R ≤ r → IsCompact (closedBall x r)) : ProperSpace α
⟨fun x r => IsCompact.of_isClosed_subset (h x (max r R) (le_max_right _ _)) isClosed_closedBall (closedBall_subset_closedBall <| le_max_left _ _)⟩
theorem
ProperSpace.of_isCompact_closedBall_of_le
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "IsCompact", "IsCompact.of_isClosed_subset", "ProperSpace" ]
If all closed balls of large enough radius are compact, then the space is proper. Especially useful when the lower bound for the radius is 0.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ProperSpace.of_seq_closedBall {β : Type*} {l : Filter β} [NeBot l] {x : α} {r : β → ℝ} (hr : Tendsto r l atTop) (hc : ∀ᶠ i in l, IsCompact (closedBall x (r i))) : ProperSpace α
where isCompact_closedBall a r := let ⟨_i, hci, hir⟩ := (hc.and <| hr.eventually_ge_atTop <| r + dist a x).exists hci.of_isClosed_subset isClosed_closedBall <| closedBall_subset_closedBall' hir
theorem
ProperSpace.of_seq_closedBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "Filter", "IsCompact", "ProperSpace" ]
If there exists a sequence of compact closed balls with the same center such that the radii tend to infinity, then the space is proper.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
prod_properSpace {α : Type*} {β : Type*} [PseudoMetricSpace α] [PseudoMetricSpace β] [ProperSpace α] [ProperSpace β] : ProperSpace (α × β)
where isCompact_closedBall := by rintro ⟨x, y⟩ r rw [← closedBall_prod_same x y] exact (isCompact_closedBall x r).prod (isCompact_closedBall y r)
instance
prod_properSpace
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "ProperSpace", "PseudoMetricSpace", "closedBall_prod_same" ]
A binary product of proper spaces is proper.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
pi_properSpace {X : β → Type*} [Fintype β] [∀ b, PseudoMetricSpace (X b)] [h : ∀ b, ProperSpace (X b)] : ProperSpace (∀ b, X b)
by refine .of_isCompact_closedBall_of_le 0 fun x r hr => ?_ rw [closedBall_pi _ hr] exact isCompact_univ_pi fun _ => isCompact_closedBall _ _
instance
pi_properSpace
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "Fintype", "ProperSpace", "PseudoMetricSpace", "closedBall_pi", "isCompact_univ_pi" ]
A finite product of proper spaces is proper.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ProperSpace.of_isClosed {X : Type*} [PseudoMetricSpace X] [ProperSpace X] {s : Set X} (hs : IsClosed s) : ProperSpace s
⟨fun x r ↦ Topology.IsEmbedding.subtypeVal.isCompact_iff.mpr ((isCompact_closedBall x.1 r).of_isClosed_subset (hs.isClosedMap_subtype_val _ isClosed_closedBall) (Set.image_subset_iff.mpr subset_rfl))⟩
lemma
ProperSpace.of_isClosed
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ProperSpace.lean
[]
[ "IsClosed", "ProperSpace", "PseudoMetricSpace", "Set", "subset_rfl" ]
A closed subspace of a proper space is proper. This is true for any proper lipschitz map. See `LipschitzWith.properSpace`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_subseq_of_frequently_bounded (hs : IsBounded s) {x : ℕ → X} (hx : ∃ᶠ n in atTop, x n ∈ s) : ∃ a ∈ closure s, ∃ φ : ℕ → ℕ, StrictMono φ ∧ Tendsto (x ∘ φ) atTop (𝓝 a)
have hcs : IsSeqCompact (closure s) := hs.isCompact_closure.isSeqCompact have hu' : ∃ᶠ n in atTop, x n ∈ closure s := hx.mono fun _n hn => subset_closure hn hcs.subseq_of_frequently_in hu'
theorem
tendsto_subseq_of_frequently_bounded
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Sequences.lean
[]
[ "IsSeqCompact", "StrictMono", "closure", "subset_closure" ]
A version of **Bolzano-Weierstrass**: in a proper metric space (e.g. $ℝ^n$), every bounded sequence has a converging subsequence. This version assumes only that the sequence is frequently in some bounded set.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
tendsto_subseq_of_bounded (hs : IsBounded s) {x : ℕ → X} (hx : ∀ n, x n ∈ s) : ∃ a ∈ closure s, ∃ φ : ℕ → ℕ, StrictMono φ ∧ Tendsto (x ∘ φ) atTop (𝓝 a)
tendsto_subseq_of_frequently_bounded hs <| Frequently.of_forall hx
theorem
tendsto_subseq_of_bounded
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Sequences.lean
[]
[ "StrictMono", "closure", "tendsto_subseq_of_frequently_bounded" ]
A version of **Bolzano-Weierstrass**: in a proper metric space (e.g. $ℝ^n$), every bounded sequence has a converging subsequence.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_subset_iUnion_ball_radius_lt {r : ι → ℝ} (hs : IsClosed s) (uf : ∀ x ∈ s, { i | x ∈ ball (c i) (r i) }.Finite) (us : s ⊆ ⋃ i, ball (c i) (r i)) : ∃ r' : ι → ℝ, (s ⊆ ⋃ i, ball (c i) (r' i)) ∧ ∀ i, r' i < r i
by rcases exists_subset_iUnion_closed_subset hs (fun i => @isOpen_ball _ _ (c i) (r i)) uf us with ⟨v, hsv, hvc, hcv⟩ have := fun i => exists_lt_subset_ball (hvc i) (hcv i) choose r' hlt hsub using this exact ⟨r', hsv.trans <| iUnion_mono <| hsub, hlt⟩
theorem
exists_subset_iUnion_ball_radius_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ShrinkingLemma.lean
[]
[ "Finite", "IsClosed", "exists_lt_subset_ball", "exists_subset_iUnion_closed_subset" ]
**Shrinking lemma** for coverings by open balls in a proper metric space. A point-finite open cover of a closed subset of a proper metric space by open balls can be shrunk to a new cover by open balls so that each of the new balls has strictly smaller radius than the old one. This version assumes that `fun x ↦ ball (c ...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_iUnion_ball_eq_radius_lt {r : ι → ℝ} (uf : ∀ x, { i | x ∈ ball (c i) (r i) }.Finite) (uU : ⋃ i, ball (c i) (r i) = univ) : ∃ r' : ι → ℝ, ⋃ i, ball (c i) (r' i) = univ ∧ ∀ i, r' i < r i
let ⟨r', hU, hv⟩ := exists_subset_iUnion_ball_radius_lt isClosed_univ (fun x _ => uf x) uU.ge ⟨r', univ_subset_iff.1 hU, hv⟩
theorem
exists_iUnion_ball_eq_radius_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ShrinkingLemma.lean
[]
[ "Finite", "exists_subset_iUnion_ball_radius_lt", "isClosed_univ" ]
Shrinking lemma for coverings by open balls in a proper metric space. A point-finite open cover of a proper metric space by open balls can be shrunk to a new cover by open balls so that each of the new balls has strictly smaller radius than the old one.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_subset_iUnion_ball_radius_pos_lt {r : ι → ℝ} (hr : ∀ i, 0 < r i) (hs : IsClosed s) (uf : ∀ x ∈ s, { i | x ∈ ball (c i) (r i) }.Finite) (us : s ⊆ ⋃ i, ball (c i) (r i)) : ∃ r' : ι → ℝ, (s ⊆ ⋃ i, ball (c i) (r' i)) ∧ ∀ i, r' i ∈ Ioo 0 (r i)
by rcases exists_subset_iUnion_closed_subset hs (fun i => @isOpen_ball _ _ (c i) (r i)) uf us with ⟨v, hsv, hvc, hcv⟩ have := fun i => exists_pos_lt_subset_ball (hr i) (hvc i) (hcv i) choose r' hlt hsub using this exact ⟨r', hsv.trans <| iUnion_mono hsub, hlt⟩
theorem
exists_subset_iUnion_ball_radius_pos_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ShrinkingLemma.lean
[]
[ "Finite", "IsClosed", "exists_pos_lt_subset_ball", "exists_subset_iUnion_closed_subset" ]
Shrinking lemma for coverings by open balls in a proper metric space. A point-finite open cover of a closed subset of a proper metric space by nonempty open balls can be shrunk to a new cover by nonempty open balls so that each of the new balls has strictly smaller radius than the old one.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_iUnion_ball_eq_radius_pos_lt {r : ι → ℝ} (hr : ∀ i, 0 < r i) (uf : ∀ x, { i | x ∈ ball (c i) (r i) }.Finite) (uU : ⋃ i, ball (c i) (r i) = univ) : ∃ r' : ι → ℝ, ⋃ i, ball (c i) (r' i) = univ ∧ ∀ i, r' i ∈ Ioo 0 (r i)
let ⟨r', hU, hv⟩ := exists_subset_iUnion_ball_radius_pos_lt hr isClosed_univ (fun x _ => uf x) uU.ge ⟨r', univ_subset_iff.1 hU, hv⟩
theorem
exists_iUnion_ball_eq_radius_pos_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ShrinkingLemma.lean
[]
[ "Finite", "exists_subset_iUnion_ball_radius_pos_lt", "isClosed_univ" ]
Shrinking lemma for coverings by open balls in a proper metric space. A point-finite open cover of a proper metric space by nonempty open balls can be shrunk to a new cover by nonempty open balls so that each of the new balls has strictly smaller radius than the old one.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_locallyFinite_subset_iUnion_ball_radius_lt (hs : IsClosed s) {R : α → ℝ} (hR : ∀ x ∈ s, 0 < R x) : ∃ (ι : Type u) (c : ι → α) (r r' : ι → ℝ), (∀ i, c i ∈ s ∧ 0 < r i ∧ r i < r' i ∧ r' i < R (c i)) ∧ (LocallyFinite fun i => ball (c i) (r' i)) ∧ s ⊆ ⋃ i, ball (c i) (r i)
by have : ∀ x ∈ s, (𝓝 x).HasBasis (fun r : ℝ => 0 < r ∧ r < R x) fun r => ball x r := fun x hx => nhds_basis_uniformity (uniformity_basis_dist_lt (hR x hx)) rcases refinement_of_locallyCompact_sigmaCompact_of_nhds_basis_set hs this with ⟨ι, c, r', hr', hsub', hfin⟩ rcases exists_subset_iUnion_ball_radius...
theorem
exists_locallyFinite_subset_iUnion_ball_radius_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ShrinkingLemma.lean
[]
[ "IsClosed", "LocallyFinite", "exists_subset_iUnion_ball_radius_pos_lt", "nhds_basis_uniformity", "refinement_of_locallyCompact_sigmaCompact_of_nhds_basis_set" ]
Let `R : α → ℝ` be a (possibly discontinuous) function on a proper metric space. Let `s` be a closed set in `α` such that `R` is positive on `s`. Then there exists a collection of pairs of balls `Metric.ball (c i) (r i)`, `Metric.ball (c i) (r' i)` such that * all centers belong to `s`; * for all `i` we have `0 < r i ...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
exists_locallyFinite_iUnion_eq_ball_radius_lt {R : α → ℝ} (hR : ∀ x, 0 < R x) : ∃ (ι : Type u) (c : ι → α) (r r' : ι → ℝ), (∀ i, 0 < r i ∧ r i < r' i ∧ r' i < R (c i)) ∧ (LocallyFinite fun i => ball (c i) (r' i)) ∧ ⋃ i, ball (c i) (r i) = univ
let ⟨ι, c, r, r', hlt, hfin, hsub⟩ := exists_locallyFinite_subset_iUnion_ball_radius_lt isClosed_univ fun x _ => hR x ⟨ι, c, r, r', fun i => (hlt i).2, hfin, univ_subset_iff.1 hsub⟩
theorem
exists_locallyFinite_iUnion_eq_ball_radius_lt
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ShrinkingLemma.lean
[]
[ "LocallyFinite", "exists_locallyFinite_subset_iUnion_ball_radius_lt", "isClosed_univ" ]
Let `R : α → ℝ` be a (possibly discontinuous) positive function on a proper metric space. Then there exists a collection of pairs of balls `Metric.ball (c i) (r i)`, `Metric.ball (c i) (r' i)` such that * for all `i` we have `0 < r i < r' i < R (c i)`; * the family of balls `Metric.ball (c i) (r' i)` is locally finite...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Similar (v₁ : ι → P₁) (v₂ : ι → P₂) : Prop
∃ r : ℝ≥0, r ≠ 0 ∧ ∀ (i₁ i₂ : ι), (edist (v₁ i₁) (v₁ i₂) = r * edist (v₂ i₁) (v₂ i₂)) @[inherit_doc] scoped[Similar] infixl:25 " ∼ " => Similar
def
Similar
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[]
Similarity between indexed sets of vertices v₁ and v₂. Use `open scoped Similar` to access the `v₁ ∼ v₂` notation.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_edist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ≥0, r ≠ 0 ∧ ∀ (i₁ i₂ : ι), (edist (v₁ i₁) (v₁ i₂) = r * edist (v₂ i₁) (v₂ i₂)))
Iff.rfl
lemma
similar_iff_exists_edist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Similar" ]
Similarity holds if and only if all extended distances are proportional.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_pairwise_edist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ≥0, r ≠ 0 ∧ Pairwise fun i₁ i₂ ↦ (edist (v₁ i₁) (v₁ i₂) = r * edist (v₂ i₁) (v₂ i₂)))
by rw [similar_iff_exists_edist_eq] refine ⟨?_, ?_⟩ <;> rintro ⟨r, hr, h⟩ <;> refine ⟨r, hr, fun i₁ i₂ ↦ ?_⟩ · exact fun _ ↦ h i₁ i₂ · by_cases hi : i₁ = i₂ · simp [hi] · exact h hi
lemma
similar_iff_exists_pairwise_edist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Pairwise", "Similar", "by_cases", "similar_iff_exists_edist_eq" ]
Similarity holds if and only if all extended distances between points with different indices are proportional.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Congruent.similar {v₁ : ι → P₁} {v₂ : ι → P₂} (h : Congruent v₁ v₂) : Similar v₁ v₂
⟨1, one_ne_zero, fun i₁ i₂ ↦ by simpa using h i₁ i₂⟩
lemma
Congruent.similar
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Congruent", "Similar", "one_ne_zero" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
refl (v₁ : ι → P₁) : v₁ ∼ v₁
⟨1, one_ne_zero, fun _ _ => by {norm_cast; rw [one_mul]}⟩
lemma
Similar.refl
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "one_mul", "one_ne_zero", "refl" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
symm (h : v₁ ∼ v₂) : v₂ ∼ v₁
by rcases h with ⟨r, hr, h⟩ refine ⟨r⁻¹, inv_ne_zero hr, fun _ _ => ?_⟩ rw [ENNReal.coe_inv hr, ← ENNReal.div_eq_inv_mul, ENNReal.eq_div_iff _ ENNReal.coe_ne_top, h] norm_cast
lemma
Similar.symm
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "ENNReal.coe_inv", "ENNReal.coe_ne_top", "ENNReal.div_eq_inv_mul", "ENNReal.eq_div_iff", "inv_ne_zero", "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
_root_.similar_comm : v₁ ∼ v₂ ↔ v₂ ∼ v₁
⟨Similar.symm, Similar.symm⟩
lemma
similar_comm
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
trans (h₁ : v₁ ∼ v₂) (h₂ : v₂ ∼ v₃) : v₁ ∼ v₃
by rcases h₁ with ⟨r₁, hr₁, h₁⟩; rcases h₂ with ⟨r₂, hr₂, h₂⟩ refine ⟨r₁ * r₂, mul_ne_zero hr₁ hr₂, fun _ _ => ?_⟩ rw [ENNReal.coe_mul, mul_assoc, h₁, h₂]
lemma
Similar.trans
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "ENNReal.coe_mul", "mul_assoc", "mul_ne_zero", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
index_map (h : v₁ ∼ v₂) (f : ι' → ι) : (v₁ ∘ f) ∼ (v₂ ∘ f)
by rcases h with ⟨r, hr, h⟩ refine ⟨r, hr, fun _ _ => ?_⟩ apply h
lemma
Similar.index_map
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[]
Change the index set ι to an index ι' that maps to ι.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
index_equiv (f : ι' ≃ ι) (v₁ : ι → P₁) (v₂ : ι → P₂) : v₁ ∘ f ∼ v₂ ∘ f ↔ v₁ ∼ v₂
by refine ⟨fun h => ?_, fun h => Similar.index_map h f⟩ rcases h with ⟨r, hr, h⟩ refine ⟨r, hr, fun i₁ i₂ => ?_⟩ simpa [f.right_inv i₁, f.right_inv i₂] using h (f.symm i₁) (f.symm i₂)
lemma
Similar.index_equiv
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Similar.index_map" ]
Change between equivalent index sets ι and ι'.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
of_subsingleton_index [Subsingleton ι] : v₁ ∼ v₂
Congruent.of_subsingleton_index.similar
lemma
Similar.of_subsingleton_index
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[]
Families with at most a single point are always similar.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_left [FunLike F P₁ P₃] [DilationClass F P₁ P₃] (f : F) (h : v₁ ∼ v₂) : f ∘ v₁ ∼ v₂
.trans ⟨Dilation.ratio f, Dilation.ratio_ne_zero f, fun _ _ => Dilation.edist_eq f _ _⟩ h
lemma
Similar.comp_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Dilation.edist_eq", "Dilation.ratio_ne_zero", "DilationClass", "FunLike", "trans" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_right [FunLike F P₂ P₃] [DilationClass F P₂ P₃] (f : F) (h : v₁ ∼ v₂) : v₁ ∼ f ∘ v₂
.symm (h.symm.comp_left f)
lemma
Similar.comp_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "DilationClass", "FunLike", "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_left_iff [FunLike F P₁ P₃] [DilationClass F P₁ P₃] (f : F) : f ∘ v₁ ∼ v₂ ↔ v₁ ∼ v₂
⟨.trans <| .comp_right f (.refl _), .comp_left f⟩
lemma
Similar.comp_left_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "DilationClass", "FunLike", "refl" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_right_iff [FunLike F P₂ P₃] [DilationClass F P₂ P₃] (f : F) : v₁ ∼ f ∘ v₂ ↔ v₁ ∼ v₂
by rw [similar_comm, comp_left_iff, similar_comm]
lemma
Similar.comp_right_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "DilationClass", "FunLike", "similar_comm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_isometry_left {f : P₁ → P₃} (hf : Isometry f) (h : v₁ ∼ v₂) : f ∘ v₁ ∼ v₂
comp_left hf.toDilation h
lemma
Similar.comp_isometry_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Isometry" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_isometry_right {f : P₂ → P₃} (hf : Isometry f) (h : v₁ ∼ v₂) : v₁ ∼ f ∘ v₂
comp_right hf.toDilation h
lemma
Similar.comp_isometry_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Isometry" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_isometry_left_iff {f : P₁ → P₃} (hf : Isometry f) : f ∘ v₁ ∼ v₂ ↔ v₁ ∼ v₂
comp_left_iff hf.toDilation
lemma
Similar.comp_isometry_left_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Isometry" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comp_isometry_right_iff {f : P₂ → P₃} (hf : Isometry f) : v₁ ∼ f ∘ v₂ ↔ v₁ ∼ v₂
comp_right_iff hf.toDilation
lemma
Similar.comp_isometry_right_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Isometry" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comm_left (h : ![a, b, c] ∼ ![a', b', c']) : ![b, a, c] ∼ ![b', a', c']
by have hl : ![b, a, c] = ![a, b, c] ∘ Equiv.swap 0 1 := by ext i fin_cases i <;> simp [Equiv.swap_apply_of_ne_of_ne] have hr : ![b', a', c'] = ![a', b', c'] ∘ Equiv.swap 0 1 := by ext i fin_cases i <;> simp [Equiv.swap_apply_of_ne_of_ne] grind [index_equiv]
theorem
Similar.comm_left
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Equiv.swap", "Equiv.swap_apply_of_ne_of_ne" ]
Swapping the first two vertices preserves similarity.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
comm_right (h : ![a, b, c] ∼ ![a', b', c']) : ![a, c, b] ∼ ![a', c', b']
by have hl : ![a, c, b] = ![a, b, c] ∘ Equiv.swap 1 2 := by ext i fin_cases i <;> simp [Equiv.swap_apply_of_ne_of_ne] have hr : ![a', c', b'] = ![a', b', c'] ∘ Equiv.swap 1 2 := by ext i fin_cases i <;> simp [Equiv.swap_apply_of_ne_of_ne] grind [index_equiv]
theorem
Similar.comm_right
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Equiv.swap", "Equiv.swap_apply_of_ne_of_ne" ]
Swapping the last two vertices preserves similarity.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
reverse_of_three (h : ![a, b, c] ∼ ![a', b', c']) : ![c, b, a] ∼ ![c', b', a']
h.comm_left.comm_right.comm_left
theorem
Similar.reverse_of_three
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[]
Reversing the order of vertices preserves similarity.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_nndist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ≥0, r ≠ 0 ∧ ∀ (i₁ i₂ : ι), (nndist (v₁ i₁) (v₁ i₂) = r * nndist (v₂ i₁) (v₂ i₂)))
exists_congr <| fun _ => and_congr Iff.rfl <| forall₂_congr <| fun _ _ => by { rw [edist_nndist, edist_nndist]; norm_cast }
lemma
similar_iff_exists_nndist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Similar", "edist_nndist" ]
Similarity holds if and only if all non-negative distances are proportional.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_pairwise_nndist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ≥0, r ≠ 0 ∧ Pairwise fun i₁ i₂ ↦ (nndist (v₁ i₁) (v₁ i₂) = r * nndist (v₂ i₁) (v₂ i₂)))
by simp_rw [similar_iff_exists_pairwise_edist_eq, edist_nndist] exact_mod_cast Iff.rfl
lemma
similar_iff_exists_pairwise_nndist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Pairwise", "Similar", "edist_nndist", "similar_iff_exists_pairwise_edist_eq" ]
Similarity holds if and only if all non-negative distances between points with different indices are proportional.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_dist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ≥0, r ≠ 0 ∧ ∀ (i₁ i₂ : ι), (dist (v₁ i₁) (v₁ i₂) = r * dist (v₂ i₁) (v₂ i₂)))
similar_iff_exists_nndist_eq.trans (exists_congr <| fun _ => and_congr Iff.rfl <| forall₂_congr <| fun _ _ => by { rw [dist_nndist, dist_nndist]; norm_cast })
lemma
similar_iff_exists_dist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Similar", "dist_nndist" ]
Similarity holds if and only if all distances are proportional.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_pairwise_dist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ≥0, r ≠ 0 ∧ Pairwise fun i₁ i₂ ↦ (dist (v₁ i₁) (v₁ i₂) = r * dist (v₂ i₁) (v₂ i₂)))
by simp_rw [similar_iff_exists_pairwise_nndist_eq, dist_nndist] exact_mod_cast Iff.rfl
lemma
similar_iff_exists_pairwise_dist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Pairwise", "Similar", "dist_nndist", "similar_iff_exists_pairwise_nndist_eq" ]
Similarity holds if and only if all distances between points with different indices are proportional.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_pos_dist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ, 0 < r ∧ ∀ (i₁ i₂ : ι), (dist (v₁ i₁) (v₁ i₂) = r * dist (v₂ i₁) (v₂ i₂)))
by rw [similar_iff_exists_dist_eq] simp_rw [← pos_iff_ne_zero, NNReal.exists, ← NNReal.coe_pos, NNReal.coe_mk] grind
lemma
similar_iff_exists_pos_dist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "NNReal.coe_mk", "NNReal.coe_pos", "Similar", "similar_iff_exists_dist_eq" ]
Similarity holds if and only if all distances are proportional with a positive real ratio.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_iff_exists_pos_pairwise_dist_eq : Similar v₁ v₂ ↔ (∃ r : ℝ, 0 < r ∧ Pairwise fun i₁ i₂ ↦ (dist (v₁ i₁) (v₁ i₂) = r * dist (v₂ i₁) (v₂ i₂)))
by simp_rw [similar_iff_exists_pairwise_dist_eq] simp_rw [← pos_iff_ne_zero, NNReal.exists, ← NNReal.coe_pos, NNReal.coe_mk] grind
lemma
similar_iff_exists_pos_pairwise_dist_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "NNReal.coe_mk", "NNReal.coe_pos", "Pairwise", "Similar", "similar_iff_exists_pairwise_dist_eq" ]
Similarity holds iff pairwise distances are proportional with a positive ratio.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
similar_of_dist_mul_eq_dist_mul_eq (h_ne : dist a b ≠ 0) (h_ne' : dist a' b' ≠ 0) (heq1 : dist a b * dist b' c' = dist b c * dist a' b') (heq2 : dist a b * dist c' a' = dist c a * dist a' b') : Similar ![a, b, c] ![a', b', c']
by set r : ℝ := (dist a b / dist a' b') with hr have hr_pos : 0 < r := by positivity apply Similar.of_exists_pos_pairwise_dist_eq use r refine ⟨hr_pos, ?_⟩ intro i j hij fin_cases i <;> fin_cases j <;> try {rw [dist_self, dist_self, mul_zero]} all_goals simp; grind [dist_comm] alias similar_of_side_sid...
theorem
similar_of_dist_mul_eq_dist_mul_eq
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Similarity.lean
[]
[ "Similar", "dist_comm", "dist_self" ]
If two triangles have two pairs of proportional adjacent sides, then the triangles are similar.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
Snowflaking (X : Type*) (α : ℝ) (hα₀ : 0 < α) (hα₁ : α ≤ 1) where /-- The value wrapped in `x : Snowflaking X α hα₀ hα₁`. -/ val : X
structure
Metric.Snowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
A copy of a type with metric given by `dist x y = (dist x.val y.val) ^ α`. This is defined as a one-field structure.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ofSnowflaking : Snowflaking X α hα₀ hα₁ ≃ X
where toFun := val invFun := mk left_inv _ := rfl right_inv _ := rfl
def
Metric.Snowflaking.ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
The natural equivalence between `Snowflaking X α hr₀ hr₁` and `X`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toSnowflaking : X ≃ Snowflaking X α hα₀ hα₁
ofSnowflaking.symm
def
Metric.Snowflaking.toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
The natural equivalence between `X` and `Snowflaking X α hr₀ hr₁`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toSnowflaking.sizeOf_spec [SizeOf X] (x : X) : sizeOf (toSnowflaking x : Snowflaking X α hα₀ hα₁) = 1 + sizeOf x
rfl
theorem
Metric.Snowflaking.toSnowflaking.sizeOf_spec
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
casesOn_toSnowflaking {motive : Snowflaking X α hα₀ hα₁ → Sort*} (toSnowflaking : ∀ x, motive (Snowflaking.toSnowflaking x)) (x : Snowflaking X α hα₀ hα₁) : motive x
toSnowflaking x.val
def
Metric.Snowflaking.casesOn_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
This definition makes `cases x` and `induction x` use `toSnowflaking` instead of `mk`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
mk_eq_toSnowflaking : (mk : X → Snowflaking X α hα₀ hα₁) = toSnowflaking
rfl
theorem
Metric.Snowflaking.mk_eq_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
val_eq_ofSnowflaking : (val : Snowflaking X α hα₀ hα₁ → X) = ofSnowflaking
rfl
theorem
Metric.Snowflaking.val_eq_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
symm_toSnowflaking : (toSnowflaking : X ≃ Snowflaking X α hα₀ hα₁).symm = ofSnowflaking
rfl
theorem
Metric.Snowflaking.symm_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
symm_ofSnowflaking : (ofSnowflaking : Snowflaking X α hα₀ hα₁ ≃ X).symm = toSnowflaking
rfl
theorem
Metric.Snowflaking.symm_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "symm" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toSnowflaking_ofSnowflaking (x : Snowflaking X α hα₀ hα₁) : toSnowflaking x.ofSnowflaking = x
rfl
theorem
Metric.Snowflaking.toSnowflaking_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ofSnowflaking_toSnowflaking (x : X) : (toSnowflaking x : Snowflaking X α hα₀ hα₁).ofSnowflaking = x
rfl
theorem
Metric.Snowflaking.ofSnowflaking_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ofSnowflaking_comp_toSnowflaking : (ofSnowflaking : Snowflaking X α hα₀ hα₁ → X) ∘ toSnowflaking = id
rfl
theorem
Metric.Snowflaking.ofSnowflaking_comp_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
toSnowflaking_comp_ofSnowflaking : (toSnowflaking : X → Snowflaking X α hα₀ hα₁) ∘ ofSnowflaking = id
rfl
theorem
Metric.Snowflaking.toSnowflaking_comp_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_toSnowflaking_eq_preimage (s : Set X) : (toSnowflaking '' s : Set (Snowflaking X α hα₀ hα₁)) = ofSnowflaking ⁻¹' s
toSnowflaking.image_eq_preimage_symm _
theorem
Metric.Snowflaking.image_toSnowflaking_eq_preimage
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_ofSnowflaking_eq_preimage (s : Set (Snowflaking X α hα₀ hα₁)) : ofSnowflaking '' s = toSnowflaking ⁻¹' s
ofSnowflaking.image_eq_preimage_symm _
theorem
Metric.Snowflaking.image_ofSnowflaking_eq_preimage
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_toSnowflaking_image_ofSnowflaking (s : Set (Snowflaking X α hα₀ hα₁)) : toSnowflaking '' ofSnowflaking '' s = s
ofSnowflaking.symm_image_image _
theorem
Metric.Snowflaking.image_toSnowflaking_image_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_ofSnowflaking_image_toSnowflaking (s : Set X) : ofSnowflaking '' (toSnowflaking '' s : Set (Snowflaking X α hα₀ hα₁)) = s
ofSnowflaking.image_symm_image _
theorem
Metric.Snowflaking.image_ofSnowflaking_image_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuous_ofSnowflaking : Continuous (ofSnowflaking : Snowflaking X α hα₀ hα₁ → X)
continuous_induced_dom
theorem
Metric.Snowflaking.continuous_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Continuous", "continuous_induced_dom" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuous_toSnowflaking : Continuous (toSnowflaking : X → Snowflaking X α hα₀ hα₁)
continuous_induced_rng.2 continuous_id
theorem
Metric.Snowflaking.continuous_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Continuous", "continuous_id" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
homeomorph : Snowflaking X α hα₀ hα₁ ≃ₜ X
where toEquiv := ofSnowflaking continuous_invFun := continuous_toSnowflaking
def
Metric.Snowflaking.homeomorph
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
The natural homeomorphism between `Snowflaking X α hα₀ hα₁` and `X`.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBounded_image_ofSnowflaking_iff {s : Set (Snowflaking X α hα₀ hα₁)} : IsBounded (ofSnowflaking '' s) ↔ IsBounded s
isBounded_induced.symm
theorem
Metric.Snowflaking.isBounded_image_ofSnowflaking_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBounded_preimage_toSnowflaking_iff {s : Set (Snowflaking X α hα₀ hα₁)} : IsBounded (toSnowflaking ⁻¹' s) ↔ IsBounded s
by rw [← image_ofSnowflaking_eq_preimage, isBounded_image_ofSnowflaking_iff]
theorem
Metric.Snowflaking.isBounded_preimage_toSnowflaking_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBounded_image_toSnowflaking_iff {s : Set X} : IsBounded (toSnowflaking '' s : Set (Snowflaking X α hα₀ hα₁)) ↔ IsBounded s
by rw [← isBounded_image_ofSnowflaking_iff, image_ofSnowflaking_image_toSnowflaking]
theorem
Metric.Snowflaking.isBounded_image_toSnowflaking_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
isBounded_preimage_ofSnowflaking_iff {s : Set X} : IsBounded (ofSnowflaking ⁻¹' s : Set (Snowflaking X α hα₀ hα₁)) ↔ IsBounded s
by rw [← image_toSnowflaking_eq_preimage, isBounded_image_toSnowflaking_iff]
theorem
Metric.Snowflaking.isBounded_preimage_ofSnowflaking_iff
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_ofSnowflaking : UniformContinuous (ofSnowflaking : Snowflaking X α hα₀ hα₁ → X)
uniformContinuous_comap
theorem
Metric.Snowflaking.uniformContinuous_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "UniformContinuous", "uniformContinuous_comap" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformContinuous_toSnowflaking : UniformContinuous (toSnowflaking : X → Snowflaking X α hα₀ hα₁)
uniformContinuous_comap' uniformContinuous_id
theorem
Metric.Snowflaking.uniformContinuous_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "UniformContinuous", "uniformContinuous_comap'", "uniformContinuous_id" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
uniformEquiv : Snowflaking X α hα₀ hα₁ ≃ᵤ X
where toEquiv := ofSnowflaking uniformContinuous_toFun := uniformContinuous_ofSnowflaking uniformContinuous_invFun := uniformContinuous_toSnowflaking
def
Metric.Snowflaking.uniformEquiv
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
The natural uniform space equivalence between `Snowflaking X α hα hα₁` and the underlying space.
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
edist_def (x y : Snowflaking X α hα₀ hα₁) : edist x y = edist x.ofSnowflaking y.ofSnowflaking ^ α
rfl
theorem
Metric.Snowflaking.edist_def
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
edist_toSnowflaking_toSnowflaking (x y : X) : edist (toSnowflaking x : Snowflaking X α hα₀ hα₁) (toSnowflaking y) = edist x y ^ α
rfl
theorem
Metric.Snowflaking.edist_toSnowflaking_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
edist_ofSnowflaking_ofSnowflaking (x y : Snowflaking X α hα₀ hα₁) : edist x.ofSnowflaking y.ofSnowflaking = edist x y ^ α⁻¹
by rw [edist_def, ENNReal.rpow_rpow_inv hα₀.ne']
theorem
Metric.Snowflaking.edist_ofSnowflaking_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_rpow_inv" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_ofSnowflaking_eball (x : X) (r : ℝ≥0∞) : ofSnowflaking ⁻¹' Metric.eball x r = Metric.eball (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by ext ⟨y⟩ simp (disch := positivity) [ENNReal.rpow_lt_rpow_iff] @[deprecated (since := "2026-01-24")] alias preimage_ofSnowflaking_emetricBall := preimage_ofSnowflaking_eball
theorem
Metric.Snowflaking.preimage_ofSnowflaking_eball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_lt_rpow_iff", "Metric.eball" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_toSnowflaking_eball (x : X) (r : ℝ≥0∞) : toSnowflaking '' Metric.eball x r = Metric.eball (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by rw [image_toSnowflaking_eq_preimage, preimage_ofSnowflaking_eball] @[deprecated (since := "2026-01-24")] alias image_toSnowflaking_emetricBall := image_toSnowflaking_eball
theorem
Metric.Snowflaking.image_toSnowflaking_eball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Metric.eball" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_toSnowflaking_eball (x : Snowflaking X α hα₀ hα₁) (d : ℝ≥0∞) : toSnowflaking ⁻¹' Metric.eball x d = Metric.eball x.ofSnowflaking (d ^ α⁻¹)
by rw [toSnowflaking.preimage_eq_iff_eq_image, image_toSnowflaking_eball, toSnowflaking_ofSnowflaking, ENNReal.rpow_inv_rpow hα₀.ne'] @[deprecated (since := "2026-01-24")] alias preimage_toSnowflaking_emetricBall := preimage_toSnowflaking_eball
theorem
Metric.Snowflaking.preimage_toSnowflaking_eball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_inv_rpow", "Metric.eball" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_ofSnowflaking_eball (x : Snowflaking X α hα₀ hα₁) (d : ℝ≥0∞) : ofSnowflaking '' Metric.eball x d = Metric.eball x.ofSnowflaking (d ^ α⁻¹)
by rw [image_ofSnowflaking_eq_preimage, preimage_toSnowflaking_eball] @[deprecated (since := "2026-01-24")] alias image_ofSnowflaking_emetricBall := image_ofSnowflaking_eball
theorem
Metric.Snowflaking.image_ofSnowflaking_eball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Metric.eball" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_ofSnowflaking_closedEBall (x : X) (r : ℝ≥0∞) : ofSnowflaking ⁻¹' Metric.closedEBall x r = Metric.closedEBall (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by ext ⟨y⟩ simp (disch := positivity) [ENNReal.rpow_le_rpow_iff] @[deprecated (since := "2026-01-24")] alias preimage_ofSnowflaking_emetricClosedBall := preimage_ofSnowflaking_closedEBall
theorem
Metric.Snowflaking.preimage_ofSnowflaking_closedEBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_le_rpow_iff", "Metric.closedEBall" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_toSnowflaking_closedEBall (x : X) (r : ℝ≥0∞) : toSnowflaking '' Metric.closedEBall x r = Metric.closedEBall (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by rw [image_toSnowflaking_eq_preimage, preimage_ofSnowflaking_closedEBall] @[deprecated (since := "2026-01-24")] alias image_toSnowflaking_emetricClosedBall := image_toSnowflaking_closedEBall
theorem
Metric.Snowflaking.image_toSnowflaking_closedEBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Metric.closedEBall" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_toSnowflaking_closedEBall (x : Snowflaking X α hα₀ hα₁) (d : ℝ≥0∞) : toSnowflaking ⁻¹' Metric.closedEBall x d = Metric.closedEBall x.ofSnowflaking (d ^ α⁻¹)
by rw [toSnowflaking.preimage_eq_iff_eq_image, image_toSnowflaking_closedEBall, toSnowflaking_ofSnowflaking, ENNReal.rpow_inv_rpow hα₀.ne'] @[deprecated (since := "2026-01-24")] alias preimage_toSnowflaking_emetricClosedBall := preimage_toSnowflaking_closedEBall
theorem
Metric.Snowflaking.preimage_toSnowflaking_closedEBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_inv_rpow", "Metric.closedEBall" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_ofSnowflaking_closedEBall (x : Snowflaking X α hα₀ hα₁) (d : ℝ≥0∞) : ofSnowflaking '' Metric.closedEBall x d = Metric.closedEBall x.ofSnowflaking (d ^ α⁻¹)
by rw [image_ofSnowflaking_eq_preimage, preimage_toSnowflaking_closedEBall] @[deprecated (since := "2026-01-24")] alias image_ofSnowflaking_emetricClosedBall := image_ofSnowflaking_closedEBall
theorem
Metric.Snowflaking.image_ofSnowflaking_closedEBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Metric.closedEBall" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ediam_image_ofSnowflaking (s : Set (Snowflaking X α hα₀ hα₁)) : ediam (ofSnowflaking '' s) = ediam s ^ α⁻¹
by refine eq_of_forall_ge_iff fun c ↦ ?_ simp only [ENNReal.rpow_inv_le_iff hα₀, ediam_le_iff, Set.forall_mem_image, edist_ofSnowflaking_ofSnowflaking]
theorem
Metric.Snowflaking.ediam_image_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_inv_le_iff", "Set", "Set.forall_mem_image" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ediam_preimage_toSnowflaking (s : Set (Snowflaking X α hα₀ hα₁)) : ediam (toSnowflaking ⁻¹' s) = ediam s ^ α⁻¹
by rw [← image_ofSnowflaking_eq_preimage, ediam_image_ofSnowflaking]
theorem
Metric.Snowflaking.ediam_preimage_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ediam_preimage_ofSnowflaking (s : Set X) : ediam (ofSnowflaking ⁻¹' s : Set (Snowflaking X α hα₀ hα₁)) = ediam s ^ α
by rw [← ENNReal.rpow_inv_rpow hα₀.ne' (ediam _), ← ediam_preimage_toSnowflaking, ← Set.preimage_comp, ofSnowflaking_comp_toSnowflaking, Set.preimage_id]
theorem
Metric.Snowflaking.ediam_preimage_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "ENNReal.rpow_inv_rpow", "Set", "Set.preimage_comp", "Set.preimage_id" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
ediam_image_toSnowflaking (s : Set X) : ediam (toSnowflaking '' s : Set (Snowflaking X α hα₀ hα₁)) = ediam s ^ α
by simp [image_toSnowflaking_eq_preimage]
theorem
Metric.Snowflaking.ediam_image_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Set" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_toSnowflaking_toSnowflaking [Dist X] (x y : X) : dist (toSnowflaking x : Snowflaking X α hα₀ hα₁) (toSnowflaking y) = dist x y ^ α
rfl
theorem
Metric.Snowflaking.dist_toSnowflaking_toSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Dist" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
dist_ofSnowflaking_ofSnowflaking (x y : Snowflaking X α hα₀ hα₁) : dist x.ofSnowflaking y.ofSnowflaking = dist x y ^ α⁻¹
by cases x; cases y simp [Real.rpow_rpow_inv dist_nonneg hα₀.ne']
theorem
Metric.Snowflaking.dist_ofSnowflaking_ofSnowflaking
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Real.rpow_rpow_inv", "dist_nonneg" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_ofSnowflaking_ball (x : X) {r : ℝ} (hr : 0 ≤ r) : ofSnowflaking ⁻¹' ball x r = ball (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by ext ⟨y⟩ simp (disch := positivity) [Real.rpow_lt_rpow_iff]
theorem
Metric.Snowflaking.preimage_ofSnowflaking_ball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Real.rpow_lt_rpow_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_toSnowflaking_ball (x : X) {r : ℝ} (hr : 0 ≤ r) : toSnowflaking '' ball x r = ball (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by rw [image_toSnowflaking_eq_preimage, preimage_ofSnowflaking_ball x hr]
theorem
Metric.Snowflaking.image_toSnowflaking_ball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_toSnowflaking_ball (x : Snowflaking X α hα₀ hα₁) {r : ℝ} (hr : 0 ≤ r) : toSnowflaking ⁻¹' ball x r = ball x.ofSnowflaking (r ^ α⁻¹)
by rw [toSnowflaking.preimage_eq_iff_eq_image, image_toSnowflaking_ball _ (by positivity), toSnowflaking_ofSnowflaking, Real.rpow_inv_rpow hr hα₀.ne']
theorem
Metric.Snowflaking.preimage_toSnowflaking_ball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Real.rpow_inv_rpow" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_ofSnowflaking_ball (x : Snowflaking X α hα₀ hα₁) {r : ℝ} (hr : 0 ≤ r) : ofSnowflaking '' ball x r = ball x.ofSnowflaking (r ^ α⁻¹)
by rw [image_ofSnowflaking_eq_preimage, preimage_toSnowflaking_ball _ hr]
theorem
Metric.Snowflaking.image_ofSnowflaking_ball
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_ofSnowflaking_closedBall (x : X) {r : ℝ} (hr : 0 ≤ r) : ofSnowflaking ⁻¹' closedBall x r = closedBall (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by ext ⟨y⟩ simp (disch := positivity) [Real.rpow_le_rpow_iff]
theorem
Metric.Snowflaking.preimage_ofSnowflaking_closedBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Real.rpow_le_rpow_iff" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_toSnowflaking_closedBall (x : X) {r : ℝ} (hr : 0 ≤ r) : toSnowflaking '' closedBall x r = closedBall (toSnowflaking x : Snowflaking X α hα₀ hα₁) (r ^ α)
by rw [image_toSnowflaking_eq_preimage, preimage_ofSnowflaking_closedBall x hr]
theorem
Metric.Snowflaking.image_toSnowflaking_closedBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
preimage_toSnowflaking_closedBall (x : Snowflaking X α hα₀ hα₁) {r : ℝ} (hr : 0 ≤ r) : toSnowflaking ⁻¹' closedBall x r = closedBall x.ofSnowflaking (r ^ α⁻¹)
by rw [toSnowflaking.preimage_eq_iff_eq_image, image_toSnowflaking_closedBall _ (by positivity), toSnowflaking_ofSnowflaking, Real.rpow_inv_rpow hr hα₀.ne']
theorem
Metric.Snowflaking.preimage_toSnowflaking_closedBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[ "Real.rpow_inv_rpow" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
image_ofSnowflaking_closedBall (x : Snowflaking X α hα₀ hα₁) {r : ℝ} (hr : 0 ≤ r) : ofSnowflaking '' closedBall x r = closedBall x.ofSnowflaking (r ^ α⁻¹)
by rw [image_ofSnowflaking_eq_preimage, preimage_toSnowflaking_closedBall _ hr]
theorem
Metric.Snowflaking.image_ofSnowflaking_closedBall
Topology.MetricSpace
Mathlib/Topology/MetricSpace/Snowflaking.lean
[ "Mathlib.Analysis.MeanInequalitiesPow" ]
[]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
thickenedIndicatorAux (δ : ℝ) (E : Set α) : α → ℝ≥0∞
fun x : α => (1 : ℝ≥0∞) - infEDist x E / ENNReal.ofReal δ
def
thickenedIndicatorAux
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ThickenedIndicator.lean
[]
[ "ENNReal.ofReal", "Set" ]
The `δ`-thickened indicator of a set `E` is the function that equals `1` on `E` and `0` outside a `δ`-thickening of `E` and interpolates (continuously) between these values using `infEDist _ E`. `thickenedIndicatorAux` is the unbundled `ℝ≥0∞`-valued function. See `thickenedIndicator` for the (bundled) bounded continuo...
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
continuous_thickenedIndicatorAux {δ : ℝ} (δ_pos : 0 < δ) (E : Set α) : Continuous (thickenedIndicatorAux δ E)
by unfold thickenedIndicatorAux let f := fun x : α => (⟨1, infEDist x E / ENNReal.ofReal δ⟩ : ℝ≥0 × ℝ≥0∞) let sub := fun p : ℝ≥0 × ℝ≥0∞ => (p.1 : ℝ≥0∞) - p.2 rw [show (fun x : α => (1 : ℝ≥0∞) - infEDist x E / ENNReal.ofReal δ) = sub ∘ f by rfl] apply (@ENNReal.continuous_nnreal_sub 1).comp apply (ENNReal.co...
theorem
continuous_thickenedIndicatorAux
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ThickenedIndicator.lean
[]
[ "Continuous", "ENNReal.continuous_div_const", "ENNReal.continuous_nnreal_sub", "ENNReal.ofReal", "Set", "thickenedIndicatorAux" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319
thickenedIndicatorAux_le_one (δ : ℝ) (E : Set α) (x : α) : thickenedIndicatorAux δ E x ≤ 1
by apply tsub_le_self (α := ℝ≥0∞)
theorem
thickenedIndicatorAux_le_one
Topology.MetricSpace
Mathlib/Topology/MetricSpace/ThickenedIndicator.lean
[]
[ "Set", "thickenedIndicatorAux", "tsub_le_self" ]
https://github.com/leanprover-community/mathlib4
b9f14353520df73472ae3825fb53f86559a01319