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metric.uniformity_eq_comap_nhds_zero : 𝓤 α = comap (λp:α×α, dist p.1 p.2) (𝓝 (0 : ℝ))
by { ext s, simp [mem_uniformity_dist, (nhds_basis_ball.comap _).mem_iff, subset_def, real.dist_0_eq_abs] }
theorem
metric.uniformity_eq_comap_nhds_zero
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "real.dist_0_eq_abs" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_iff_tendsto_dist_at_top_0 [nonempty β] [semilattice_sup β] {u : β → α} : cauchy_seq u ↔ tendsto (λ (n : β × β), dist (u n.1) (u n.2)) at_top (𝓝 0)
by rw [cauchy_seq_iff_tendsto, metric.uniformity_eq_comap_nhds_zero, tendsto_comap_iff, prod.map_def]
lemma
cauchy_seq_iff_tendsto_dist_at_top_0
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq", "cauchy_seq_iff_tendsto", "metric.uniformity_eq_comap_nhds_zero", "prod.map_def", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_uniformity_iff_dist_tendsto_zero {ι : Type*} {f : ι → α × α} {p : filter ι} : tendsto f p (𝓤 α) ↔ tendsto (λ x, dist (f x).1 (f x).2) p (𝓝 0)
by rw [metric.uniformity_eq_comap_nhds_zero, tendsto_comap_iff]
lemma
tendsto_uniformity_iff_dist_tendsto_zero
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter", "metric.uniformity_eq_comap_nhds_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.congr_dist {ι : Type*} {f₁ f₂ : ι → α} {p : filter ι} {a : α} (h₁ : tendsto f₁ p (𝓝 a)) (h : tendsto (λ x, dist (f₁ x) (f₂ x)) p (𝓝 0)) : tendsto f₂ p (𝓝 a)
h₁.congr_uniformity $ tendsto_uniformity_iff_dist_tendsto_zero.2 h
lemma
filter.tendsto.congr_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_iff_of_dist {ι : Type*} {f₁ f₂ : ι → α} {p : filter ι} {a : α} (h : tendsto (λ x, dist (f₁ x) (f₂ x)) p (𝓝 0)) : tendsto f₁ p (𝓝 a) ↔ tendsto f₂ p (𝓝 a)
uniform.tendsto_congr $ tendsto_uniformity_iff_dist_tendsto_zero.2 h
lemma
tendsto_iff_of_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter", "uniform.tendsto_congr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eventually_closed_ball_subset {x : α} {u : set α} (hu : u ∈ 𝓝 x) : ∀ᶠ r in 𝓝 (0 : ℝ), closed_ball x r ⊆ u
begin obtain ⟨ε, εpos, hε⟩ : ∃ ε (hε : 0 < ε), closed_ball x ε ⊆ u := nhds_basis_closed_ball.mem_iff.1 hu, have : Iic ε ∈ 𝓝 (0 : ℝ) := Iic_mem_nhds εpos, filter_upwards [this] with _ hr using subset.trans (closed_ball_subset_closed_ball hr) hε, end
lemma
eventually_closed_ball_subset
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "Iic_mem_nhds" ]
If `u` is a neighborhood of `x`, then for small enough `r`, the closed ball `closed_ball x r` is contained in `u`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
metric.cauchy_seq_iff {u : β → α} : cauchy_seq u ↔ ∀ε>0, ∃N, ∀m n≥N, dist (u m) (u n) < ε
uniformity_basis_dist.cauchy_seq_iff
theorem
metric.cauchy_seq_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq" ]
In a pseudometric space, Cauchy sequences are characterized by the fact that, eventually, the distance between its elements is arbitrarily small
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
metric.cauchy_seq_iff' {u : β → α} : cauchy_seq u ↔ ∀ε>0, ∃N, ∀n≥N, dist (u n) (u N) < ε
uniformity_basis_dist.cauchy_seq_iff'
theorem
metric.cauchy_seq_iff'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq" ]
A variation around the pseudometric characterization of Cauchy sequences
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
metric.uniform_cauchy_seq_on_iff {γ : Type*} {F : β → γ → α} {s : set γ} : uniform_cauchy_seq_on F at_top s ↔ ∀ ε : ℝ, ε > 0 → ∃ (N : β), ∀ m : β, m ≥ N → ∀ n : β, n ≥ N → ∀ x : γ, x ∈ s → dist (F m x) (F n x) < ε
begin split, { intros h ε hε, let u := { a : α × α | dist a.fst a.snd < ε }, have hu : u ∈ 𝓤 α := metric.mem_uniformity_dist.mpr ⟨ε, hε, (λ a b, by simp)⟩, rw ←@filter.eventually_at_top_prod_self' _ _ _ (λ m, ∀ x : γ, x ∈ s → dist (F m.fst x) (F m.snd x) < ε), specialize h u hu, rw prod_a...
theorem
metric.uniform_cauchy_seq_on_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter.eventually_at_top_prod_self'", "uniform_cauchy_seq_on" ]
In a pseudometric space, unifom Cauchy sequences are characterized by the fact that, eventually, the distance between all its elements is uniformly, arbitrarily small
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_of_le_tendsto_0' {s : β → α} (b : β → ℝ) (h : ∀ n m : β, n ≤ m → dist (s n) (s m) ≤ b n) (h₀ : tendsto b at_top (𝓝 0)) : cauchy_seq s
metric.cauchy_seq_iff'.2 $ λ ε ε0, (h₀.eventually (gt_mem_nhds ε0)).exists.imp $ λ N hN n hn, calc dist (s n) (s N) = dist (s N) (s n) : dist_comm _ _ ... ≤ b N : h _ _ hn ... < ε : hN
lemma
cauchy_seq_of_le_tendsto_0'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq", "dist_comm", "gt_mem_nhds" ]
If the distance between `s n` and `s m`, `n ≤ m` is bounded above by `b n` and `b` converges to zero, then `s` is a Cauchy sequence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_of_le_tendsto_0 {s : β → α} (b : β → ℝ) (h : ∀ n m N : β, N ≤ n → N ≤ m → dist (s n) (s m) ≤ b N) (h₀ : tendsto b at_top (𝓝 0)) : cauchy_seq s
cauchy_seq_of_le_tendsto_0' b (λ n m hnm, h _ _ _ le_rfl hnm) h₀
lemma
cauchy_seq_of_le_tendsto_0
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq", "cauchy_seq_of_le_tendsto_0'", "le_rfl" ]
If the distance between `s n` and `s m`, `n, m ≥ N` is bounded above by `b N` and `b` converges to zero, then `s` is a Cauchy sequence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_bdd {u : ℕ → α} (hu : cauchy_seq u) : ∃ R > 0, ∀ m n, dist (u m) (u n) < R
begin rcases metric.cauchy_seq_iff'.1 hu 1 zero_lt_one with ⟨N, hN⟩, rsuffices ⟨R, R0, H⟩ : ∃ R > 0, ∀ n, dist (u n) (u N) < R, { exact ⟨_, add_pos R0 R0, λ m n, lt_of_le_of_lt (dist_triangle_right _ _ _) (add_lt_add (H m) (H n))⟩ }, let R := finset.sup (finset.range N) (λ n, nndist (u n) (u N)), refine...
theorem
cauchy_seq_bdd
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq", "dist_triangle_right", "finset.le_sup", "finset.range", "finset.sup", "zero_lt_one" ]
A Cauchy sequence on the natural numbers is bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_iff_le_tendsto_0 {s : ℕ → α} : cauchy_seq s ↔ ∃ b : ℕ → ℝ, (∀ n, 0 ≤ b n) ∧ (∀ n m N : ℕ, N ≤ n → N ≤ m → dist (s n) (s m) ≤ b N) ∧ tendsto b at_top (𝓝 0)
⟨λ hs, begin /- `s` is a Cauchy sequence. The sequence `b` will be constructed by taking the supremum of the distances between `s n` and `s m` for `n m ≥ N`. First, we prove that all these distances are bounded, as otherwise the Sup would not make sense. -/ let S := λ N, (λ(p : ℕ × ℕ), dist (s p.1) (s p.2)) '...
lemma
cauchy_seq_iff_le_tendsto_0
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "abs_of_nonneg", "bdd_above", "cSup_le", "cauchy_seq", "cauchy_seq_bdd", "cauchy_seq_of_le_tendsto_0", "dist_self", "half_pos", "le_cSup", "real.dist_0_eq_abs" ]
Yet another metric characterization of Cauchy sequences on integers. This one is often the most efficient.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space.induced {α β} (f : α → β) (m : pseudo_metric_space β) : pseudo_metric_space α
{ dist := λ x y, dist (f x) (f y), dist_self := λ x, dist_self _, dist_comm := λ x y, dist_comm _ _, dist_triangle := λ x y z, dist_triangle _ _ _, edist := λ x y, edist (f x) (f y), edist_dist := λ x y, edist_dist _ _, to_uniform_space := uniform_...
def
pseudo_metric_space.induced
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "bornology.induced", "compl_compl", "dist_comm", "dist_self", "dist_triangle", "edist_dist", "filter.mem_sets", "pseudo_metric_space", "set.ext", "uniform_space.comap" ]
Pseudometric space structure pulled back by a function.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing.comap_pseudo_metric_space {α β} [topological_space α] [pseudo_metric_space β] {f : α → β} (hf : inducing f) : pseudo_metric_space α
(pseudo_metric_space.induced f ‹_›).replace_topology hf.induced
def
inducing.comap_pseudo_metric_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "inducing", "pseudo_metric_space", "pseudo_metric_space.induced", "topological_space" ]
Pull back a pseudometric space structure by an inducing map. This is a version of `pseudo_metric_space.induced` useful in case if the domain already has a `topological_space` structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_inducing.comap_pseudo_metric_space {α β} [uniform_space α] [pseudo_metric_space β] (f : α → β) (h : uniform_inducing f) : pseudo_metric_space α
(pseudo_metric_space.induced f ‹_›).replace_uniformity h.comap_uniformity.symm
def
uniform_inducing.comap_pseudo_metric_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "pseudo_metric_space", "pseudo_metric_space.induced", "uniform_inducing", "uniform_space" ]
Pull back a pseudometric space structure by a uniform inducing map. This is a version of `pseudo_metric_space.induced` useful in case if the domain already has a `uniform_space` structure.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subtype.pseudo_metric_space {p : α → Prop} : pseudo_metric_space (subtype p)
pseudo_metric_space.induced coe ‹_›
instance
subtype.pseudo_metric_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "pseudo_metric_space", "pseudo_metric_space.induced" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subtype.dist_eq {p : α → Prop} (x y : subtype p) : dist x y = dist (x : α) y
rfl
theorem
subtype.dist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subtype.nndist_eq {p : α → Prop} (x y : subtype p) : nndist x y = nndist (x : α) y
rfl
theorem
subtype.nndist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_unop (x y : αᵐᵒᵖ) : dist (unop x) (unop y) = dist x y
rfl
theorem
mul_opposite.dist_unop
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_op (x y : α) : dist (op x) (op y) = dist x y
rfl
theorem
mul_opposite.dist_op
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_unop (x y : αᵐᵒᵖ) : nndist (unop x) (unop y) = nndist x y
rfl
theorem
mul_opposite.nndist_unop
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_op (x y : α) : nndist (op x) (op y) = nndist x y
rfl
theorem
mul_opposite.nndist_op
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.dist_eq (a b : ℝ≥0) : dist a b = |(a:ℝ) - b|
rfl
lemma
nnreal.dist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.nndist_eq (a b : ℝ≥0) : nndist a b = max (a - b) (b - a)
begin wlog h : b ≤ a, { rw [nndist_comm, max_comm], exact this b a (le_of_not_le h) }, rw [← nnreal.coe_eq, ← dist_nndist, nnreal.dist_eq, tsub_eq_zero_iff_le.2 h, max_eq_left (zero_le $ a - b), ← nnreal.coe_sub h, abs_of_nonneg (a - b).coe_nonneg], end
lemma
nnreal.nndist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "abs_of_nonneg", "dist_nndist", "nndist_comm", "nnreal.coe_eq", "nnreal.coe_sub", "nnreal.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.nndist_zero_eq_val (z : ℝ≥0) : nndist 0 z = z
by simp only [nnreal.nndist_eq, max_eq_right, tsub_zero, zero_tsub, zero_le']
lemma
nnreal.nndist_zero_eq_val
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "nnreal.nndist_eq", "tsub_zero", "zero_le'", "zero_tsub" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.nndist_zero_eq_val' (z : ℝ≥0) : nndist z 0 = z
by { rw nndist_comm, exact nnreal.nndist_zero_eq_val z, }
lemma
nnreal.nndist_zero_eq_val'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "nndist_comm", "nnreal.nndist_zero_eq_val" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.le_add_nndist (a b : ℝ≥0) : a ≤ b + nndist a b
begin suffices : (a : ℝ) ≤ (b : ℝ) + (dist a b), { exact nnreal.coe_le_coe.mp this, }, linarith [le_of_abs_le (by refl : abs (a-b : ℝ) ≤ (dist a b))], end
lemma
nnreal.le_add_nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "le_of_abs_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift.dist_eq (x y : ulift β) : dist x y = dist x.down y.down
rfl
lemma
ulift.dist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift.nndist_eq (x y : ulift β) : nndist x y = nndist x.down y.down
rfl
lemma
ulift.nndist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift.dist_up_up (x y : β) : dist (ulift.up x) (ulift.up y) = dist x y
rfl
lemma
ulift.dist_up_up
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift.nndist_up_up (x y : β) : nndist (ulift.up x) (ulift.up y) = nndist x y
rfl
lemma
ulift.nndist_up_up
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod.pseudo_metric_space_max : pseudo_metric_space (α × β)
(pseudo_emetric_space.to_pseudo_metric_space_of_dist (λ x y : α × β, dist x.1 y.1 ⊔ dist x.2 y.2) (λ x y, (max_lt (edist_lt_top _ _) (edist_lt_top _ _)).ne) (λ x y, by simp only [sup_eq_max, dist_edist, ← ennreal.to_real_max (edist_ne_top _ _) (edist_ne_top _ _), prod.edist_eq])) .replace_bornology $ λ ...
instance
prod.pseudo_metric_space_max
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_edist", "edist_lt_top", "edist_ne_top", "ennreal.to_real_max", "forall_and_distrib", "max_le_iff", "prod.edist_eq", "pseudo_emetric_space.to_pseudo_metric_space_of_dist", "pseudo_metric_space", "sup_eq_max" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod.dist_eq {x y : α × β} : dist x y = max (dist x.1 y.1) (dist x.2 y.2)
rfl
lemma
prod.dist_eq
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_prod_same_left {x : α} {y₁ y₂ : β} : dist (x, y₁) (x, y₂) = dist y₁ y₂
by simp [prod.dist_eq, dist_nonneg]
lemma
dist_prod_same_left
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nonneg", "prod.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_prod_same_right {x₁ x₂ : α} {y : β} : dist (x₁, y) (x₂, y) = dist x₁ x₂
by simp [prod.dist_eq, dist_nonneg]
lemma
dist_prod_same_right
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nonneg", "prod.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_prod_same (x : α) (y : β) (r : ℝ) : ball x r ×ˢ ball y r = ball (x, y) r
ext $ λ z, by simp [prod.dist_eq]
theorem
ball_prod_same
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "prod.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_prod_same (x : α) (y : β) (r : ℝ) : closed_ball x r ×ˢ closed_ball y r = closed_ball (x, y) r
ext $ λ z, by simp [prod.dist_eq]
theorem
closed_ball_prod_same
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "prod.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sphere_prod (x : α × β) (r : ℝ) : sphere x r = sphere x.1 r ×ˢ closed_ball x.2 r ∪ closed_ball x.1 r ×ˢ sphere x.2 r
begin obtain hr | rfl | hr := lt_trichotomy r 0, { simp [hr], }, { cases x, simp_rw [←closed_ball_eq_sphere_of_nonpos le_rfl, union_self, closed_ball_prod_same] }, { ext ⟨x', y'⟩, simp_rw [set.mem_union, set.mem_prod, metric.mem_closed_ball, metric.mem_sphere, prod.dist_eq, max_eq_iff], refine...
theorem
sphere_prod
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "and_congr_left", "closed_ball_prod_same", "le_rfl", "max_eq_iff", "metric.mem_closed_ball", "metric.mem_sphere", "prod.dist_eq", "set.mem_prod", "set.mem_union" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_continuous_dist : uniform_continuous (λp:α×α, dist p.1 p.2)
metric.uniform_continuous_iff.2 (λ ε ε0, ⟨ε/2, half_pos ε0, begin suffices, { intros p q h, cases p with p₁ p₂, cases q with q₁ q₂, cases max_lt_iff.1 h with h₁ h₂, clear h, dsimp at h₁ h₂ ⊢, rw real.dist_eq, refine abs_sub_lt_iff.2 ⟨_, _⟩, { revert p₁ p₂ q₁ q₂ h₁ h₂, exact this }, { apply t...
theorem
uniform_continuous_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "abs_dist_sub_le", "add_halves", "dist_comm", "half_pos", "real.dist_eq", "uniform_continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_continuous.dist [uniform_space β] {f g : β → α} (hf : uniform_continuous f) (hg : uniform_continuous g) : uniform_continuous (λb, dist (f b) (g b))
uniform_continuous_dist.comp (hf.prod_mk hg)
theorem
uniform_continuous.dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "uniform_continuous", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_dist : continuous (λp:α×α, dist p.1 p.2)
uniform_continuous_dist.continuous
theorem
continuous_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.dist [topological_space β] {f g : β → α} (hf : continuous f) (hg : continuous g) : continuous (λb, dist (f b) (g b))
continuous_dist.comp (hf.prod_mk hg : _)
theorem
continuous.dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.dist {f g : β → α} {x : filter β} {a b : α} (hf : tendsto f x (𝓝 a)) (hg : tendsto g x (𝓝 b)) : tendsto (λx, dist (f x) (g x)) x (𝓝 (dist a b))
(continuous_dist.tendsto (a, b)).comp (hf.prod_mk_nhds hg)
theorem
filter.tendsto.dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_comap_dist (a : α) : (𝓝 (0 : ℝ)).comap (λa', dist a' a) = 𝓝 a
by simp only [@nhds_eq_comap_uniformity α, metric.uniformity_eq_comap_nhds_zero, comap_comap, (∘), dist_comm]
lemma
nhds_comap_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "metric.uniformity_eq_comap_nhds_zero", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_iff_dist_tendsto_zero {f : β → α} {x : filter β} {a : α} : (tendsto f x (𝓝 a)) ↔ (tendsto (λb, dist (f b) a) x (𝓝 0))
by rw [← nhds_comap_dist a, tendsto_comap_iff]
lemma
tendsto_iff_dist_tendsto_zero
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter", "nhds_comap_dist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_iff_continuous_dist [topological_space β] {f : β → α} : continuous f ↔ continuous (λ x : β × β, dist (f x.1) (f x.2))
⟨λ h, (h.comp continuous_fst).dist (h.comp continuous_snd), λ h, continuous_iff_continuous_at.2 $ λ x, tendsto_iff_dist_tendsto_zero.2 $ (h.comp (continuous_id.prod_mk continuous_const)).tendsto' _ _ $ dist_self _⟩
lemma
continuous_iff_continuous_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous", "continuous_const", "continuous_fst", "continuous_snd", "dist_self", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_continuous_nndist : uniform_continuous (λp:α×α, nndist p.1 p.2)
uniform_continuous_dist.subtype_mk _
lemma
uniform_continuous_nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "uniform_continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_continuous.nndist [uniform_space β] {f g : β → α} (hf : uniform_continuous f) (hg : uniform_continuous g) : uniform_continuous (λ b, nndist (f b) (g b))
uniform_continuous_nndist.comp (hf.prod_mk hg)
lemma
uniform_continuous.nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "uniform_continuous", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_nndist : continuous (λp:α×α, nndist p.1 p.2)
uniform_continuous_nndist.continuous
lemma
continuous_nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.nndist [topological_space β] {f g : β → α} (hf : continuous f) (hg : continuous g) : continuous (λb, nndist (f b) (g b))
continuous_nndist.comp (hf.prod_mk hg : _)
lemma
continuous.nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.nndist {f g : β → α} {x : filter β} {a b : α} (hf : tendsto f x (𝓝 a)) (hg : tendsto g x (𝓝 b)) : tendsto (λx, nndist (f x) (g x)) x (𝓝 (nndist a b))
(continuous_nndist.tendsto (a, b)).comp (hf.prod_mk_nhds hg)
theorem
filter.tendsto.nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed_ball : is_closed (closed_ball x ε)
is_closed_le (continuous_id.dist continuous_const) continuous_const
theorem
metric.is_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_const", "is_closed", "is_closed_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed_sphere : is_closed (sphere x ε)
is_closed_eq (continuous_id.dist continuous_const) continuous_const
lemma
metric.is_closed_sphere
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_const", "is_closed", "is_closed_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_closed_ball : closure (closed_ball x ε) = closed_ball x ε
is_closed_ball.closure_eq
theorem
metric.closure_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_sphere : closure (sphere x ε) = sphere x ε
is_closed_sphere.closure_eq
theorem
metric.closure_sphere
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_ball_subset_closed_ball : closure (ball x ε) ⊆ closed_ball x ε
closure_minimal ball_subset_closed_ball is_closed_ball
theorem
metric.closure_ball_subset_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "closure_minimal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frontier_ball_subset_sphere : frontier (ball x ε) ⊆ sphere x ε
frontier_lt_subset_eq (continuous_id.dist continuous_const) continuous_const
theorem
metric.frontier_ball_subset_sphere
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_const", "frontier", "frontier_lt_subset_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frontier_closed_ball_subset_sphere : frontier (closed_ball x ε) ⊆ sphere x ε
frontier_le_subset_eq (continuous_id.dist continuous_const) continuous_const
theorem
metric.frontier_closed_ball_subset_sphere
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_const", "frontier", "frontier_le_subset_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_subset_interior_closed_ball : ball x ε ⊆ interior (closed_ball x ε)
interior_maximal ball_subset_closed_ball is_open_ball
theorem
metric.ball_subset_interior_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "interior", "interior_maximal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_closure_iff {s : set α} {a : α} : a ∈ closure s ↔ ∀ε>0, ∃b ∈ s, dist a b < ε
(mem_closure_iff_nhds_basis nhds_basis_ball).trans $ by simp only [mem_ball, dist_comm]
theorem
metric.mem_closure_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "dist_comm", "mem_closure_iff", "mem_closure_iff_nhds_basis" ]
ε-characterization of the closure in pseudometric spaces
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_closure_range_iff {e : β → α} {a : α} : a ∈ closure (range e) ↔ ∀ε>0, ∃ k : β, dist a (e k) < ε
by simp only [mem_closure_iff, exists_range_iff]
lemma
metric.mem_closure_range_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_closure_range_iff_nat {e : β → α} {a : α} : a ∈ closure (range e) ↔ ∀n : ℕ, ∃ k : β, dist a (e k) < 1 / ((n : ℝ) + 1)
(mem_closure_iff_nhds_basis nhds_basis_ball_inv_nat_succ).trans $ by simp only [mem_ball, dist_comm, exists_range_iff, forall_const]
lemma
metric.mem_closure_range_iff_nat
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "dist_comm", "forall_const", "mem_closure_iff_nhds_basis" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_of_closed' {s : set α} (hs : is_closed s) {a : α} : a ∈ s ↔ ∀ε>0, ∃b ∈ s, dist a b < ε
by simpa only [hs.closure_eq] using @mem_closure_iff _ _ s a
theorem
metric.mem_of_closed'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_closed", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_zero' (x : α) : closed_ball x 0 = closure {x}
subset.antisymm (λ y hy, mem_closure_iff.2 $ λ ε ε0, ⟨x, mem_singleton x, (mem_closed_ball.1 hy).trans_lt ε0⟩) (closure_minimal (singleton_subset_iff.2 (dist_self x).le) is_closed_ball)
lemma
metric.closed_ball_zero'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "closure_minimal", "dist_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_iff {s : set α} : dense s ↔ ∀ x, ∀ r > 0, (ball x r ∩ s).nonempty
forall_congr $ λ x, by simp only [mem_closure_iff, set.nonempty, exists_prop, mem_inter_iff, mem_ball', and_comm]
lemma
metric.dense_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dense", "exists_prop", "mem_closure_iff", "set.nonempty" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_range_iff {f : β → α} : dense_range f ↔ ∀ x, ∀ r > 0, ∃ y, dist x (f y) < r
forall_congr $ λ x, by simp only [mem_closure_iff, exists_range_iff]
lemma
metric.dense_range_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dense_range", "mem_closure_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.topological_space.is_separable.separable_space {s : set α} (hs : is_separable s) : separable_space s
begin classical, rcases eq_empty_or_nonempty s with rfl|⟨⟨x₀, x₀s⟩⟩, { apply_instance }, rcases hs with ⟨c, hc, h'c⟩, haveI : encodable c := hc.to_encodable, obtain ⟨u, -, u_pos, u_lim⟩ : ∃ (u : ℕ → ℝ), strict_anti u ∧ (∀ (n : ℕ), 0 < u n) ∧ tendsto u at_top (𝓝 0) := exists_seq_strict_anti_tendsto (0 :...
lemma
topological_space.is_separable.separable_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "add_halves", "dist_triangle", "encodable", "exists_seq_strict_anti_tendsto", "half_pos", "is_separable", "metric.ball", "strict_anti" ]
If a set `s` is separable, then the corresponding subtype is separable in a metric space. This is not obvious, as the countable set whose closure covers `s` does not need in general to be contained in `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.inducing.is_separable_preimage {f : β → α} [topological_space β] (hf : inducing f) {s : set α} (hs : is_separable s) : is_separable (f ⁻¹' s)
begin haveI : second_countable_topology s, { haveI : separable_space s := hs.separable_space, exact uniform_space.second_countable_of_separable _ }, let g : f ⁻¹' s → s := cod_restrict (f ∘ coe) s (λ x, x.2), have : inducing g := (hf.comp inducing_coe).cod_restrict _, haveI : second_countable_topology (f ...
lemma
inducing.is_separable_preimage
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_subtype_coe", "inducing", "inducing_coe", "is_separable", "subtype.range_coe_subtype", "topological_space", "uniform_space.second_countable_of_separable" ]
The preimage of a separable set by an inducing map is separable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.embedding.is_separable_preimage {f : β → α} [topological_space β] (hf : embedding f) {s : set α} (hs : is_separable s) : is_separable (f ⁻¹' s)
hf.to_inducing.is_separable_preimage hs
lemma
embedding.is_separable_preimage
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "embedding", "is_separable", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.continuous_on.is_separable_image [topological_space β] {f : α → β} {s : set α} (hf : continuous_on f s) (hs : is_separable s) : is_separable (f '' s)
begin rw show f '' s = s.restrict f '' univ, by ext ; simp, exact (is_separable_univ_iff.2 hs.separable_space).image (continuous_on_iff_continuous_restrict.1 hf), end
lemma
continuous_on.is_separable_image
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_on", "is_separable", "topological_space" ]
If a map is continuous on a separable set `s`, then the image of `s` is also separable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space_pi : pseudo_metric_space (Πb, π b)
begin /- we construct the instance from the pseudoemetric space instance to avoid checking again that the uniformity is the same as the product uniformity, but we register nevertheless a nice formula for the distance -/ refine (pseudo_emetric_space.to_pseudo_metric_space_of_dist (λf g : Π b, π b, ((sup univ...
instance
pseudo_metric_space_pi
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "bot_lt_top", "dist_nndist", "edist_lt_top", "edist_nndist", "ennreal.coe_finset_sup", "ennreal.coe_to_real", "finset.mem_univ", "finset.sup_lt_iff", "function.eval_apply", "lift", "pseudo_emetric_space.to_pseudo_metric_space_of_dist", "pseudo_metric_space" ]
A finite product of pseudometric spaces is a pseudometric space, with the sup distance.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_pi_def (f g : Πb, π b) : nndist f g = sup univ (λb, nndist (f b) (g b))
nnreal.eq rfl
lemma
nndist_pi_def
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "nnreal.eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_def (f g : Πb, π b) : dist f g = (sup univ (λb, nndist (f b) (g b)) : ℝ≥0)
rfl
lemma
dist_pi_def
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_pi_le_iff {f g : Πb, π b} {r : ℝ≥0} : nndist f g ≤ r ↔ ∀b, nndist (f b) (g b) ≤ r
by simp [nndist_pi_def]
lemma
nndist_pi_le_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "nndist_pi_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_pi_lt_iff {f g : Πb, π b} {r : ℝ≥0} (hr : 0 < r) : nndist f g < r ↔ ∀ b, nndist (f b) (g b) < r
by simp [nndist_pi_def, finset.sup_lt_iff (show ⊥ < r, from hr)]
lemma
nndist_pi_lt_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "finset.sup_lt_iff", "nndist_pi_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_pi_eq_iff {f g : Π b, π b} {r : ℝ≥0} (hr : 0 < r) : nndist f g = r ↔ (∃ i, nndist (f i) (g i) = r) ∧ ∀ b, nndist (f b) (g b) ≤ r
begin rw [eq_iff_le_not_lt, nndist_pi_lt_iff hr, nndist_pi_le_iff, not_forall, and_comm], simp_rw [not_lt, and.congr_left_iff, le_antisymm_iff], intro h, refine exists_congr (λ b, _), apply (and_iff_right $ h _).symm, end
lemma
nndist_pi_eq_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "and.congr_left_iff", "eq_iff_le_not_lt", "nndist_pi_le_iff", "nndist_pi_lt_iff", "not_forall" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_lt_iff {f g : Πb, π b} {r : ℝ} (hr : 0 < r) : dist f g < r ↔ ∀b, dist (f b) (g b) < r
begin lift r to ℝ≥0 using hr.le, exact nndist_pi_lt_iff hr, end
lemma
dist_pi_lt_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "lift", "nndist_pi_lt_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_le_iff {f g : Πb, π b} {r : ℝ} (hr : 0 ≤ r) : dist f g ≤ r ↔ ∀b, dist (f b) (g b) ≤ r
begin lift r to ℝ≥0 using hr, exact nndist_pi_le_iff end
lemma
dist_pi_le_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "lift", "nndist_pi_le_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_eq_iff {f g : Πb, π b} {r : ℝ} (hr : 0 < r) : dist f g = r ↔ (∃ i, dist (f i) (g i) = r) ∧ ∀ b, dist (f b) (g b) ≤ r
begin lift r to ℝ≥0 using hr.le, simp_rw [←coe_nndist, nnreal.coe_eq, nndist_pi_eq_iff hr, nnreal.coe_le_coe], end
lemma
dist_pi_eq_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "lift", "nndist_pi_eq_iff", "nnreal.coe_eq", "nnreal.coe_le_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_le_iff' [nonempty β] {f g : Π b, π b} {r : ℝ} : dist f g ≤ r ↔ ∀ b, dist (f b) (g b) ≤ r
begin by_cases hr : 0 ≤ r, { exact dist_pi_le_iff hr }, { exact iff_of_false (λ h, hr $ dist_nonneg.trans h) (λ h, hr $ dist_nonneg.trans $ h $ classical.arbitrary _) } end
lemma
dist_pi_le_iff'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "classical.arbitrary", "dist_pi_le_iff", "iff_of_false" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_const_le (a b : α) : dist (λ _ : β, a) (λ _, b) ≤ dist a b
(dist_pi_le_iff dist_nonneg).2 $ λ _, le_rfl
lemma
dist_pi_const_le
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nonneg", "dist_pi_le_iff", "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_pi_const_le (a b : α) : nndist (λ _ : β, a) (λ _, b) ≤ nndist a b
nndist_pi_le_iff.2 $ λ _, le_rfl
lemma
nndist_pi_const_le
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "le_rfl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pi_const [nonempty β] (a b : α) : dist (λ x : β, a) (λ _, b) = dist a b
by simpa only [dist_edist] using congr_arg ennreal.to_real (edist_pi_const a b)
lemma
dist_pi_const
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_edist", "edist_pi_const", "ennreal.to_real" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_pi_const [nonempty β] (a b : α) : nndist (λ x : β, a) (λ _, b) = nndist a b
nnreal.eq $ dist_pi_const a b
lemma
nndist_pi_const
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_pi_const", "nnreal.eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nndist_le_pi_nndist (f g : Πb, π b) (b : β) : nndist (f b) (g b) ≤ nndist f g
by { rw [nndist_pi_def], exact finset.le_sup (finset.mem_univ b) }
lemma
nndist_le_pi_nndist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "finset.le_sup", "finset.mem_univ", "nndist_pi_def" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_le_pi_dist (f g : Πb, π b) (b : β) : dist (f b) (g b) ≤ dist f g
by simp only [dist_nndist, nnreal.coe_le_coe, nndist_le_pi_nndist f g b]
lemma
dist_le_pi_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nndist", "nndist_le_pi_nndist", "nnreal.coe_le_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_pi (x : Πb, π b) {r : ℝ} (hr : 0 < r) : ball x r = set.pi univ (λ b, ball (x b) r)
by { ext p, simp [dist_pi_lt_iff hr] }
lemma
ball_pi
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_pi_lt_iff", "set.pi" ]
An open ball in a product space is a product of open balls. See also `metric.ball_pi'` for a version assuming `nonempty β` instead of `0 < r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_pi' [nonempty β] (x : Π b, π b) (r : ℝ) : ball x r = set.pi univ (λ b, ball (x b) r)
(lt_or_le 0 r).elim (ball_pi x) $ λ hr, by simp [ball_eq_empty.2 hr]
lemma
ball_pi'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "ball_pi", "set.pi" ]
An open ball in a product space is a product of open balls. See also `metric.ball_pi` for a version assuming `0 < r` instead of `nonempty β`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_pi (x : Πb, π b) {r : ℝ} (hr : 0 ≤ r) : closed_ball x r = set.pi univ (λ b, closed_ball (x b) r)
by { ext p, simp [dist_pi_le_iff hr] }
lemma
closed_ball_pi
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_pi_le_iff", "set.pi" ]
A closed ball in a product space is a product of closed balls. See also `metric.closed_ball_pi'` for a version assuming `nonempty β` instead of `0 ≤ r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_ball_pi' [nonempty β] (x : Π b, π b) (r : ℝ) : closed_ball x r = set.pi univ (λ b, closed_ball (x b) r)
(le_or_lt 0 r).elim (closed_ball_pi x) $ λ hr, by simp [closed_ball_eq_empty.2 hr]
lemma
closed_ball_pi'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closed_ball_pi", "set.pi" ]
A closed ball in a product space is a product of closed balls. See also `metric.closed_ball_pi` for a version assuming `0 ≤ r` instead of `nonempty β`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sphere_pi (x : Πb, π b) {r : ℝ} (h : 0 < r ∨ nonempty β) : sphere x r = (⋃ i : β, function.eval i ⁻¹' sphere (x i) r) ∩ closed_ball x r
begin obtain hr | rfl | hr := lt_trichotomy r 0, { simp [hr], }, { rw [closed_ball_eq_sphere_of_nonpos le_rfl, eq_comm, set.inter_eq_right_iff_subset], letI := h.resolve_left (lt_irrefl _), inhabit β, refine subset_Union_of_subset default _, intros x hx, replace hx := hx.le, rw [dist_pi_le...
lemma
sphere_pi
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nonneg", "dist_pi_eq_iff", "dist_pi_le_iff", "function.eval", "le_rfl", "set.inter_eq_right_iff_subset" ]
A sphere in a product space is a union of spheres on each component restricted to the closed ball.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin.nndist_insert_nth_insert_nth {n : ℕ} {α : fin (n + 1) → Type*} [Π i, pseudo_metric_space (α i)] (i : fin (n + 1)) (x y : α i) (f g : Π j, α (i.succ_above j)) : nndist (i.insert_nth x f) (i.insert_nth y g) = max (nndist x y) (nndist f g)
eq_of_forall_ge_iff $ λ c, by simp [nndist_pi_le_iff, i.forall_iff_succ_above]
lemma
fin.nndist_insert_nth_insert_nth
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "eq_of_forall_ge_iff", "nndist_pi_le_iff", "pseudo_metric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fin.dist_insert_nth_insert_nth {n : ℕ} {α : fin (n + 1) → Type*} [Π i, pseudo_metric_space (α i)] (i : fin (n + 1)) (x y : α i) (f g : Π j, α (i.succ_above j)) : dist (i.insert_nth x f) (i.insert_nth y g) = max (dist x y) (dist f g)
by simp only [dist_nndist, fin.nndist_insert_nth_insert_nth, nnreal.coe_max]
lemma
fin.dist_insert_nth_insert_nth
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nndist", "fin.nndist_insert_nth_insert_nth", "nnreal.coe_max", "pseudo_metric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
real.dist_le_of_mem_pi_Icc {x y x' y' : β → ℝ} (hx : x ∈ Icc x' y') (hy : y ∈ Icc x' y') : dist x y ≤ dist x' y'
begin refine (dist_pi_le_iff dist_nonneg).2 (λ b, (real.dist_le_of_mem_uIcc _ _).trans (dist_le_pi_dist _ _ b)); refine Icc_subset_uIcc _, exacts [⟨hx.1 _, hx.2 _⟩, ⟨hy.1 _, hy.2 _⟩] end
lemma
real.dist_le_of_mem_pi_Icc
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_le_pi_dist", "dist_nonneg", "dist_pi_le_iff", "real.dist_le_of_mem_uIcc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
finite_cover_balls_of_compact {α : Type u} [pseudo_metric_space α] {s : set α} (hs : is_compact s) {e : ℝ} (he : 0 < e) : ∃t ⊆ s, set.finite t ∧ s ⊆ ⋃x∈t, ball x e
begin apply hs.elim_finite_subcover_image, { simp [is_open_ball] }, { intros x xs, simp, exact ⟨x, ⟨xs, by simpa⟩⟩ } end
lemma
finite_cover_balls_of_compact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact", "pseudo_metric_space", "set.finite" ]
Any compact set in a pseudometric space can be covered by finitely many balls of a given positive radius
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
proper_space (α : Type u) [pseudo_metric_space α] : Prop
(is_compact_closed_ball : ∀x:α, ∀r, is_compact (closed_ball x r))
class
proper_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact", "pseudo_metric_space" ]
A pseudometric space is proper if all closed balls are compact.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact_sphere {α : Type*} [pseudo_metric_space α] [proper_space α] (x : α) (r : ℝ) : is_compact (sphere x r)
is_compact_of_is_closed_subset (is_compact_closed_ball x r) is_closed_sphere sphere_subset_closed_ball
lemma
is_compact_sphere
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact", "is_compact_of_is_closed_subset", "proper_space", "pseudo_metric_space" ]
In a proper pseudometric space, all spheres are compact.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
second_countable_of_proper [proper_space α] : second_countable_topology α
begin -- We already have `sigma_compact_space_of_locally_compact_second_countable`, so we don't -- add an instance for `sigma_compact_space`. suffices : sigma_compact_space α, by exactI emetric.second_countable_of_sigma_compact α, rcases em (nonempty α) with ⟨⟨x⟩⟩|hn, { exact ⟨⟨λ n, closed_ball x n, λ n, is_c...
instance
second_countable_of_proper
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "em", "emetric.second_countable_of_sigma_compact", "is_compact_empty", "proper_space", "sigma_compact_space" ]
A proper pseudo metric space is sigma compact, and therefore second countable.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_dist_right_cocompact_at_top [proper_space α] (x : α) : tendsto (λ y, dist y x) (cocompact α) at_top
(has_basis_cocompact.tendsto_iff at_top_basis).2 $ λ r hr, ⟨closed_ball x r, is_compact_closed_ball x r, λ y hy, (not_le.1 $ mt mem_closed_ball.2 hy).le⟩
lemma
tendsto_dist_right_cocompact_at_top
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83