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sum.uniform_space : uniform_space (α ⊕ β)
{ to_core := uniform_space.core.sum, is_open_uniformity := λ s, ⟨uniformity_sum_of_open_aux, open_of_uniformity_sum_aux⟩ }
instance
sum.uniform_space
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open_uniformity", "uniform_space", "uniform_space.core.sum" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sum.uniformity : 𝓤 (α ⊕ β) = map (λ p : α × α, (inl p.1, inl p.2)) (𝓤 α) ⊔ map (λ p : β × β, (inr p.1, inr p.2)) (𝓤 β)
rfl
lemma
sum.uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lebesgue_number_lemma {α : Type u} [uniform_space α] {s : set α} {ι} {c : ι → set α} (hs : is_compact s) (hc₁ : ∀ i, is_open (c i)) (hc₂ : s ⊆ ⋃ i, c i) : ∃ n ∈ 𝓤 α, ∀ x ∈ s, ∃ i, {y | (x, y) ∈ n} ⊆ c i
begin let u := λ n, {x | ∃ i (m ∈ 𝓤 α), {y | (x, y) ∈ m ○ n} ⊆ c i}, have hu₁ : ∀ n ∈ 𝓤 α, is_open (u n), { refine λ n hn, is_open_uniformity.2 _, rintro x ⟨i, m, hm, h⟩, rcases comp_mem_uniformity_sets hm with ⟨m', hm', mm'⟩, apply (𝓤 α).sets_of_superset hm', rintros ⟨x, y⟩ hp rfl, refine ...
lemma
lebesgue_number_lemma
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_mem_uniformity_sets", "comp_rel_assoc", "is_compact", "is_open", "mem_comp_rel", "monotone_const", "prod_mk_mem_comp_rel", "refl_mem_uniformity", "uniform_space" ]
Let `c : ι → set α` be an open cover of a compact set `s`. Then there exists an entourage `n` such that for each `x ∈ s` its `n`-neighborhood is contained in some `c i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lebesgue_number_lemma_sUnion {α : Type u} [uniform_space α] {s : set α} {c : set (set α)} (hs : is_compact s) (hc₁ : ∀ t ∈ c, is_open t) (hc₂ : s ⊆ ⋃₀ c) : ∃ n ∈ 𝓤 α, ∀ x ∈ s, ∃ t ∈ c, ∀ y, (x, y) ∈ n → y ∈ t
by rw sUnion_eq_Union at hc₂; simpa using lebesgue_number_lemma hs (by simpa) hc₂
lemma
lebesgue_number_lemma_sUnion
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_compact", "is_open", "lebesgue_number_lemma", "uniform_space" ]
Let `c : set (set α)` be an open cover of a compact set `s`. Then there exists an entourage `n` such that for each `x ∈ s` its `n`-neighborhood is contained in some `t ∈ c`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lebesgue_number_of_compact_open [uniform_space α] {K U : set α} (hK : is_compact K) (hU : is_open U) (hKU : K ⊆ U) : ∃ V ∈ 𝓤 α, is_open V ∧ ∀ x ∈ K, uniform_space.ball x V ⊆ U
begin let W : K → set (α × α) := λ k, classical.some $ is_open_iff_open_ball_subset.mp hU k.1 $ hKU k.2, have hW : ∀ k, W k ∈ 𝓤 α ∧ is_open (W k) ∧ uniform_space.ball k.1 (W k) ⊆ U, { intros k, obtain ⟨h₁, h₂, h₃⟩ := classical.some_spec (is_open_iff_open_ball_subset.mp hU k.1 (hKU k.2)), exact ⟨h₁, h₂, h...
lemma
lebesgue_number_of_compact_open
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_mono", "interior_mem_uniformity", "interior_subset", "is_compact", "is_open", "is_open_interior", "lebesgue_number_lemma", "set_coe.exists", "uniform_space", "uniform_space.ball", "uniform_space.is_open_ball", "uniform_space.mem_ball_self" ]
A useful consequence of the Lebesgue number lemma: given any compact set `K` contained in an open set `U`, we can find an (open) entourage `V` such that the ball of size `V` about any point of `K` is contained in `U`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_nhds_right {f : filter β} {u : β → α} {a : α} : tendsto u f (𝓝 a) ↔ tendsto (λ x, (a, u x)) f (𝓤 α)
by rw [nhds_eq_comap_uniformity, tendsto_comap_iff]
theorem
uniform.tendsto_nhds_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_nhds_left {f : filter β} {u : β → α} {a : α} : tendsto u f (𝓝 a) ↔ tendsto (λ x, (u x, a)) f (𝓤 α)
by rw [nhds_eq_comap_uniformity', tendsto_comap_iff]
theorem
uniform.tendsto_nhds_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "nhds_eq_comap_uniformity'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_iff'_right [topological_space β] {f : β → α} {b : β} : continuous_at f b ↔ tendsto (λ x, (f b, f x)) (𝓝 b) (𝓤 α)
by rw [continuous_at, tendsto_nhds_right]
theorem
uniform.continuous_at_iff'_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_at", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_iff'_left [topological_space β] {f : β → α} {b : β} : continuous_at f b ↔ tendsto (λ x, (f x, f b)) (𝓝 b) (𝓤 α)
by rw [continuous_at, tendsto_nhds_left]
theorem
uniform.continuous_at_iff'_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_at", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_iff_prod [topological_space β] {f : β → α} {b : β} : continuous_at f b ↔ tendsto (λ x : β × β, (f x.1, f x.2)) (𝓝 (b, b)) (𝓤 α)
⟨λ H, le_trans (H.prod_map' H) (nhds_le_uniformity _), λ H, continuous_at_iff'_left.2 $ H.comp $ tendsto_id.prod_mk_nhds tendsto_const_nhds⟩
theorem
uniform.continuous_at_iff_prod
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_at", "nhds_le_uniformity", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_within_at_iff'_right [topological_space β] {f : β → α} {b : β} {s : set β} : continuous_within_at f s b ↔ tendsto (λ x, (f b, f x)) (𝓝[s] b) (𝓤 α)
by rw [continuous_within_at, tendsto_nhds_right]
theorem
uniform.continuous_within_at_iff'_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_within_at", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_within_at_iff'_left [topological_space β] {f : β → α} {b : β} {s : set β} : continuous_within_at f s b ↔ tendsto (λ x, (f x, f b)) (𝓝[s] b) (𝓤 α)
by rw [continuous_within_at, tendsto_nhds_left]
theorem
uniform.continuous_within_at_iff'_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_within_at", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_on_iff'_right [topological_space β] {f : β → α} {s : set β} : continuous_on f s ↔ ∀ b ∈ s, tendsto (λ x, (f b, f x)) (𝓝[s] b) (𝓤 α)
by simp [continuous_on, continuous_within_at_iff'_right]
theorem
uniform.continuous_on_iff'_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_on", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_on_iff'_left [topological_space β] {f : β → α} {s : set β} : continuous_on f s ↔ ∀ b ∈ s, tendsto (λ x, (f x, f b)) (𝓝[s] b) (𝓤 α)
by simp [continuous_on, continuous_within_at_iff'_left]
theorem
uniform.continuous_on_iff'_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_on", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_iff'_right [topological_space β] {f : β → α} : continuous f ↔ ∀ b, tendsto (λ x, (f b, f x)) (𝓝 b) (𝓤 α)
continuous_iff_continuous_at.trans $ forall_congr $ λ b, tendsto_nhds_right
theorem
uniform.continuous_iff'_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_iff'_left [topological_space β] {f : β → α} : continuous f ↔ ∀ b, tendsto (λ x, (f x, f b)) (𝓝 b) (𝓤 α)
continuous_iff_continuous_at.trans $ forall_congr $ λ b, tendsto_nhds_left
theorem
uniform.continuous_iff'_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.congr_uniformity {α β} [uniform_space β] {f g : α → β} {l : filter α} {b : β} (hf : tendsto f l (𝓝 b)) (hg : tendsto (λ x, (f x, g x)) l (𝓤 β)) : tendsto g l (𝓝 b)
uniform.tendsto_nhds_right.2 $ (uniform.tendsto_nhds_right.1 hf).uniformity_trans hg
lemma
filter.tendsto.congr_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform.tendsto_congr {α β} [uniform_space β] {f g : α → β} {l : filter α} {b : β} (hfg : tendsto (λ x, (f x, g x)) l (𝓤 β)) : tendsto f l (𝓝 b) ↔ tendsto g l (𝓝 b)
⟨λ h, h.congr_uniformity hfg, λ h, h.congr_uniformity hfg.uniformity_symm⟩
lemma
uniform.tendsto_congr
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy (f : filter α)
ne_bot f ∧ f ×ᶠ f ≤ (𝓤 α)
def
cauchy
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "filter" ]
A filter `f` is Cauchy if for every entourage `r`, there exists an `s ∈ f` such that `s × s ⊆ r`. This is a generalization of Cauchy sequences, because if `a : ℕ → α` then the filter of sets containing cofinitely many of the `a n` is Cauchy iff `a` is a Cauchy sequence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete (s : set α)
∀f, cauchy f → f ≤ 𝓟 s → ∃x∈s, f ≤ 𝓝 x
def
is_complete
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy" ]
A set `s` is called *complete*, if any Cauchy filter `f` such that `s ∈ f` has a limit in `s` (formally, it satisfies `f ≤ 𝓝 x` for some `x ∈ s`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.cauchy_iff {ι} {p : ι → Prop} {s : ι → set (α × α)} (h : (𝓤 α).has_basis p s) {f : filter α} : cauchy f ↔ (ne_bot f ∧ (∀ i, p i → ∃ t ∈ f, ∀ x y ∈ t, (x, y) ∈ s i))
and_congr iff.rfl $ (f.basis_sets.prod_self.le_basis_iff h).trans $ by simp only [subset_def, prod.forall, mem_prod_eq, and_imp, id, ball_mem_comm]
lemma
filter.has_basis.cauchy_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "and_imp", "ball_mem_comm", "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_iff' {f : filter α} : cauchy f ↔ (ne_bot f ∧ (∀ s ∈ 𝓤 α, ∃t∈f, ∀ x y ∈ t, (x, y) ∈ s))
(𝓤 α).basis_sets.cauchy_iff
lemma
cauchy_iff'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_iff {f : filter α} : cauchy f ↔ (ne_bot f ∧ (∀ s ∈ 𝓤 α, ∃t∈f, t ×ˢ t ⊆ s))
cauchy_iff'.trans $ by simp only [subset_def, prod.forall, mem_prod_eq, and_imp, id, ball_mem_comm]
lemma
cauchy_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "and_imp", "ball_mem_comm", "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.ultrafilter_of {l : filter α} (h : cauchy l) : cauchy (@ultrafilter.of _ l h.1 : filter α)
begin haveI := h.1, have := ultrafilter.of_le l, exact ⟨ultrafilter.ne_bot _, (filter.prod_mono this this).trans h.2⟩ end
lemma
cauchy.ultrafilter_of
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "filter.prod_mono", "ultrafilter.of", "ultrafilter.of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_map_iff {l : filter β} {f : β → α} : cauchy (l.map f) ↔ (ne_bot l ∧ tendsto (λp:β×β, (f p.1, f p.2)) (l ×ᶠ l) (𝓤 α))
by rw [cauchy, map_ne_bot_iff, prod_map_map_eq, tendsto]
lemma
cauchy_map_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_map_iff' {l : filter β} [hl : ne_bot l] {f : β → α} : cauchy (l.map f) ↔ tendsto (λp:β×β, (f p.1, f p.2)) (l ×ᶠ l) (𝓤 α)
cauchy_map_iff.trans $ and_iff_right hl
lemma
cauchy_map_iff'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.mono {f g : filter α} [hg : ne_bot g] (h_c : cauchy f) (h_le : g ≤ f) : cauchy g
⟨hg, le_trans (filter.prod_mono h_le h_le) h_c.right⟩
lemma
cauchy.mono
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "filter.prod_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.mono' {f g : filter α} (h_c : cauchy f) (hg : ne_bot g) (h_le : g ≤ f) : cauchy g
h_c.mono h_le
lemma
cauchy.mono'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_nhds {a : α} : cauchy (𝓝 a)
⟨nhds_ne_bot, nhds_prod_eq.symm.trans_le (nhds_le_uniformity a)⟩
lemma
cauchy_nhds
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "nhds_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_pure {a : α} : cauchy (pure a)
cauchy_nhds.mono (pure_le_nhds a)
lemma
cauchy_pure
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "pure_le_nhds" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.cauchy_map {l : filter β} [ne_bot l] {f : β → α} {a : α} (h : tendsto f l (𝓝 a)) : cauchy (map f l)
cauchy_nhds.mono h
lemma
filter.tendsto.cauchy_map
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.prod [uniform_space β] {f : filter α} {g : filter β} (hf : cauchy f) (hg : cauchy g) : cauchy (f ×ᶠ g)
begin refine ⟨hf.1.prod hg.1, _⟩, simp only [uniformity_prod, le_inf_iff, ← map_le_iff_le_comap, ← prod_map_map_eq], exact ⟨le_trans (prod_mono tendsto_fst tendsto_fst) hf.2, le_trans (prod_mono tendsto_snd tendsto_snd) hg.2⟩ end
lemma
cauchy.prod
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "le_inf_iff", "uniform_space", "uniformity_prod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_nhds_of_cauchy_adhp_aux {f : filter α} {x : α} (adhs : ∀ s ∈ 𝓤 α, ∃ t ∈ f, (t ×ˢ t ⊆ s) ∧ ∃ y, (x, y) ∈ s ∧ y ∈ t) : f ≤ 𝓝 x
begin -- Consider a neighborhood `s` of `x` assume s hs, -- Take an entourage twice smaller than `s` rcases comp_mem_uniformity_sets (mem_nhds_uniformity_iff_right.1 hs) with ⟨U, U_mem, hU⟩, -- Take a set `t ∈ f`, `t × t ⊆ U`, and a point `y ∈ t` such that `(x, y) ∈ U` rcases adhs U U_mem with ⟨t, t_mem, ht...
lemma
le_nhds_of_cauchy_adhp_aux
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "comp_mem_uniformity_sets", "filter", "prod_mk_mem_comp_rel" ]
The common part of the proofs of `le_nhds_of_cauchy_adhp` and `sequentially_complete.le_nhds_of_seq_tendsto_nhds`: if for any entourage `s` one can choose a set `t ∈ f` of diameter `s` such that it contains a point `y` with `(x, y) ∈ s`, then `f` converges to `x`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_nhds_of_cauchy_adhp {f : filter α} {x : α} (hf : cauchy f) (adhs : cluster_pt x f) : f ≤ 𝓝 x
le_nhds_of_cauchy_adhp_aux begin assume s hs, obtain ⟨t, t_mem, ht⟩ : ∃ t ∈ f, t ×ˢ t ⊆ s, from (cauchy_iff.1 hf).2 s hs, use [t, t_mem, ht], exact (forall_mem_nonempty_iff_ne_bot.2 adhs _ (inter_mem_inf (mem_nhds_left x hs) t_mem )) end
lemma
le_nhds_of_cauchy_adhp
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "cluster_pt", "filter", "le_nhds_of_cauchy_adhp_aux", "mem_nhds_left" ]
If `x` is an adherent (cluster) point for a Cauchy filter `f`, then it is a limit point for `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_nhds_iff_adhp_of_cauchy {f : filter α} {x : α} (hf : cauchy f) : f ≤ 𝓝 x ↔ cluster_pt x f
⟨assume h, cluster_pt.of_le_nhds' h hf.1, le_nhds_of_cauchy_adhp hf⟩
lemma
le_nhds_iff_adhp_of_cauchy
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "cluster_pt", "cluster_pt.of_le_nhds'", "filter", "le_nhds_of_cauchy_adhp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.map [uniform_space β] {f : filter α} {m : α → β} (hf : cauchy f) (hm : uniform_continuous m) : cauchy (map m f)
⟨hf.1.map _, calc map m f ×ᶠ map m f = map (λp:α×α, (m p.1, m p.2)) (f ×ᶠ f) : filter.prod_map_map_eq ... ≤ map (λp:α×α, (m p.1, m p.2)) (𝓤 α) : map_mono hf.right ... ≤ 𝓤 β : hm⟩
lemma
cauchy.map
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "filter.prod_map_map_eq", "uniform_continuous", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.comap [uniform_space β] {f : filter β} {m : α → β} (hf : cauchy f) (hm : comap (λp:α×α, (m p.1, m p.2)) (𝓤 β) ≤ 𝓤 α) [ne_bot (comap m f)] : cauchy (comap m f)
⟨‹_›, calc comap m f ×ᶠ comap m f = comap (λp:α×α, (m p.1, m p.2)) (f ×ᶠ f) : filter.prod_comap_comap_eq ... ≤ comap (λp:α×α, (m p.1, m p.2)) (𝓤 β) : comap_mono hf.right ... ≤ 𝓤 α : hm⟩
lemma
cauchy.comap
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "filter.prod_comap_comap_eq", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.comap' [uniform_space β] {f : filter β} {m : α → β} (hf : cauchy f) (hm : comap (λp:α×α, (m p.1, m p.2)) (𝓤 β) ≤ 𝓤 α) (hb : ne_bot (comap m f)) : cauchy (comap m f)
hf.comap hm
lemma
cauchy.comap'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq [semilattice_sup β] (u : β → α)
cauchy (at_top.map u)
def
cauchy_seq
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "semilattice_sup" ]
Cauchy sequences. Usually defined on ℕ, but often it is also useful to say that a function defined on ℝ is Cauchy at +∞ to deduce convergence. Therefore, we define it in a type class that is general enough to cover both ℕ and ℝ, which are the main motivating examples.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.tendsto_uniformity [semilattice_sup β] {u : β → α} (h : cauchy_seq u) : tendsto (prod.map u u) at_top (𝓤 α)
by simpa only [tendsto, prod_map_map_eq', prod_at_top_at_top_eq] using h.right
lemma
cauchy_seq.tendsto_uniformity
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.nonempty [semilattice_sup β] {u : β → α} (hu : cauchy_seq u) : nonempty β
@nonempty_of_ne_bot _ _ $ (map_ne_bot_iff _).1 hu.1
lemma
cauchy_seq.nonempty
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.mem_entourage {β : Type*} [semilattice_sup β] {u : β → α} (h : cauchy_seq u) {V : set (α × α)} (hV : V ∈ 𝓤 α) : ∃ k₀, ∀ i j, k₀ ≤ i → k₀ ≤ j → (u i, u j) ∈ V
begin haveI := h.nonempty, have := h.tendsto_uniformity, rw ← prod_at_top_at_top_eq at this, simpa [maps_to] using at_top_basis.prod_self.tendsto_left_iff.1 this V hV end
lemma
cauchy_seq.mem_entourage
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.cauchy_seq [semilattice_sup β] [nonempty β] {f : β → α} {x} (hx : tendsto f at_top (𝓝 x)) : cauchy_seq f
hx.cauchy_map
lemma
filter.tendsto.cauchy_seq
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_const [semilattice_sup β] [nonempty β] (x : α) : cauchy_seq (λ n : β, x)
tendsto_const_nhds.cauchy_seq
lemma
cauchy_seq_const
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_iff_tendsto [nonempty β] [semilattice_sup β] {u : β → α} : cauchy_seq u ↔ tendsto (prod.map u u) at_top (𝓤 α)
cauchy_map_iff'.trans $ by simp only [prod_at_top_at_top_eq, prod.map_def]
lemma
cauchy_seq_iff_tendsto
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "prod.map_def", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.comp_tendsto {γ} [semilattice_sup β] [semilattice_sup γ] [nonempty γ] {f : β → α} (hf : cauchy_seq f) {g : γ → β} (hg : tendsto g at_top at_top) : cauchy_seq (f ∘ g)
cauchy_seq_iff_tendsto.2 $ hf.tendsto_uniformity.comp (hg.prod_at_top hg)
lemma
cauchy_seq.comp_tendsto
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.comp_injective [semilattice_sup β] [no_max_order β] [nonempty β] {u : ℕ → α} (hu : cauchy_seq u) {f : β → ℕ} (hf : injective f) : cauchy_seq (u ∘ f)
hu.comp_tendsto $ nat.cofinite_eq_at_top ▸ hf.tendsto_cofinite.mono_left at_top_le_cofinite
lemma
cauchy_seq.comp_injective
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "nat.cofinite_eq_at_top", "no_max_order", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
function.bijective.cauchy_seq_comp_iff {f : ℕ → ℕ} (hf : bijective f) (u : ℕ → α) : cauchy_seq (u ∘ f) ↔ cauchy_seq u
begin refine ⟨λ H, _, λ H, H.comp_injective hf.injective⟩, lift f to ℕ ≃ ℕ using hf, simpa only [(∘), f.apply_symm_apply] using H.comp_injective f.symm.injective end
lemma
function.bijective.cauchy_seq_comp_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.subseq_subseq_mem {V : ℕ → set (α × α)} (hV : ∀ n, V n ∈ 𝓤 α) {u : ℕ → α} (hu : cauchy_seq u) {f g : ℕ → ℕ} (hf : tendsto f at_top at_top) (hg : tendsto g at_top at_top) : ∃ φ : ℕ → ℕ, strict_mono φ ∧ ∀ n, ((u ∘ f ∘ φ) n, (u ∘ g ∘ φ) n) ∈ V n
begin rw cauchy_seq_iff_tendsto at hu, exact ((hu.comp $ hf.prod_at_top hg).comp tendsto_at_top_diagonal).subseq_mem hV, end
lemma
cauchy_seq.subseq_subseq_mem
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "cauchy_seq_iff_tendsto", "strict_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_iff' {u : ℕ → α} : cauchy_seq u ↔ ∀ V ∈ 𝓤 α, ∀ᶠ k in at_top, k ∈ (prod.map u u) ⁻¹' V
by simpa only [cauchy_seq_iff_tendsto]
lemma
cauchy_seq_iff'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "cauchy_seq_iff_tendsto" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_iff {u : ℕ → α} : cauchy_seq u ↔ ∀ V ∈ 𝓤 α, ∃ N, ∀ k ≥ N, ∀ l ≥ N, (u k, u l) ∈ V
by simp [cauchy_seq_iff', filter.eventually_at_top_prod_self', prod_map]
lemma
cauchy_seq_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "cauchy_seq_iff'", "filter.eventually_at_top_prod_self'", "prod_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.prod_map {γ δ} [uniform_space β] [semilattice_sup γ] [semilattice_sup δ] {u : γ → α} {v : δ → β} (hu : cauchy_seq u) (hv : cauchy_seq v) : cauchy_seq (prod.map u v)
by simpa only [cauchy_seq, prod_map_map_eq', prod_at_top_at_top_eq] using hu.prod hv
lemma
cauchy_seq.prod_map
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.prod {γ} [uniform_space β] [semilattice_sup γ] {u : γ → α} {v : γ → β} (hu : cauchy_seq u) (hv : cauchy_seq v) : cauchy_seq (λ x, (u x, v x))
begin haveI := hu.nonempty, exact (hu.prod hv).mono (tendsto.prod_mk le_rfl le_rfl) end
lemma
cauchy_seq.prod
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "le_rfl", "semilattice_sup", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.eventually_eventually [semilattice_sup β] {u : β → α} (hu : cauchy_seq u) {V : set (α × α)} (hV : V ∈ 𝓤 α) : ∀ᶠ k in at_top, ∀ᶠ l in at_top, (u k, u l) ∈ V
eventually_at_top_curry $ hu.tendsto_uniformity hV
lemma
cauchy_seq.eventually_eventually
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_continuous.comp_cauchy_seq {γ} [uniform_space β] [semilattice_sup γ] {f : α → β} (hf : uniform_continuous f) {u : γ → α} (hu : cauchy_seq u) : cauchy_seq (f ∘ u)
hu.map hf
lemma
uniform_continuous.comp_cauchy_seq
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "semilattice_sup", "uniform_continuous", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.subseq_mem {V : ℕ → set (α × α)} (hV : ∀ n, V n ∈ 𝓤 α) {u : ℕ → α} (hu : cauchy_seq u) : ∃ φ : ℕ → ℕ, strict_mono φ ∧ ∀ n, (u $ φ (n + 1), u $ φ n) ∈ V n
begin have : ∀ n, ∃ N, ∀ k ≥ N, ∀ l ≥ k, (u l, u k) ∈ V n, { intro n, rw [cauchy_seq_iff] at hu, rcases hu _ (hV n) with ⟨N, H⟩, exact ⟨N, λ k hk l hl, H _ (le_trans hk hl) _ hk ⟩ }, obtain ⟨φ : ℕ → ℕ, φ_extr : strict_mono φ, hφ : ∀ n, ∀ l ≥ φ n, (u l, u $ φ n) ∈ V n⟩ := extraction_forall_of_event...
lemma
cauchy_seq.subseq_mem
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "cauchy_seq_iff", "lt_add_one", "strict_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.subseq_mem_entourage {V : ℕ → set (α × α)} (hV : ∀ n, V n ∈ 𝓤 α) {u : ℕ → α} {a : α} (hu : tendsto u at_top (𝓝 a)) : ∃ φ : ℕ → ℕ, strict_mono φ ∧ (u (φ 0), a) ∈ V 0 ∧ ∀ n, (u $ φ (n + 1), u $ φ n) ∈ V (n + 1)
begin rcases mem_at_top_sets.1 (hu (ball_mem_nhds a (symm_le_uniformity $ hV 0))) with ⟨n, hn⟩, rcases (hu.comp (tendsto_add_at_top_nat n)).cauchy_seq.subseq_mem (λ n, hV (n + 1)) with ⟨φ, φ_mono, hφV⟩, exact ⟨λ k, φ k + n, φ_mono.add_const _, hn _ le_add_self, hφV⟩ end
lemma
filter.tendsto.subseq_mem_entourage
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq.subseq_mem", "strict_mono", "symm_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_nhds_of_cauchy_seq_of_subseq [semilattice_sup β] {u : β → α} (hu : cauchy_seq u) {ι : Type*} {f : ι → β} {p : filter ι} [ne_bot p] (hf : tendsto f p at_top) {a : α} (ha : tendsto (u ∘ f) p (𝓝 a)) : tendsto u at_top (𝓝 a)
le_nhds_of_cauchy_adhp hu (map_cluster_pt_of_comp hf ha)
lemma
tendsto_nhds_of_cauchy_seq_of_subseq
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "filter", "le_nhds_of_cauchy_adhp", "map_cluster_pt_of_comp", "semilattice_sup" ]
If a Cauchy sequence has a convergent subsequence, then it converges.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.cauchy_seq_iff {γ} [nonempty β] [semilattice_sup β] {u : β → α} {p : γ → Prop} {s : γ → set (α × α)} (h : (𝓤 α).has_basis p s) : cauchy_seq u ↔ ∀ i, p i → ∃N, ∀m n≥N, (u m, u n) ∈ s i
begin rw [cauchy_seq_iff_tendsto, ← prod_at_top_at_top_eq], refine (at_top_basis.prod_self.tendsto_iff h).trans _, simp only [exists_prop, true_and, maps_to, preimage, subset_def, prod.forall, mem_prod_eq, mem_set_of_eq, mem_Ici, and_imp, prod.map, ge_iff_le, @forall_swap (_ ≤ _) β] end
lemma
filter.has_basis.cauchy_seq_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "and_imp", "cauchy_seq", "cauchy_seq_iff_tendsto", "exists_prop", "forall_swap", "ge_iff_le", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.cauchy_seq_iff' {γ} [nonempty β] [semilattice_sup β] {u : β → α} {p : γ → Prop} {s : γ → set (α × α)} (H : (𝓤 α).has_basis p s) : cauchy_seq u ↔ ∀ i, p i → ∃N, ∀n≥N, (u n, u N) ∈ s i
begin refine H.cauchy_seq_iff.trans ⟨λ h i hi, _, λ h i hi, _⟩, { exact (h i hi).imp (λ N hN n hn, hN n hn N le_rfl) }, { rcases comp_symm_of_uniformity (H.mem_of_mem hi) with ⟨t, ht, ht', hts⟩, rcases H.mem_iff.1 ht with ⟨j, hj, hjt⟩, refine (h j hj).imp (λ N hN m hm n hn, hts ⟨u N, hjt _, ht' $ hjt _⟩),...
lemma
filter.has_basis.cauchy_seq_iff'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "comp_symm_of_uniformity", "le_rfl", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_of_controlled [semilattice_sup β] [nonempty β] (U : β → set (α × α)) (hU : ∀ s ∈ 𝓤 α, ∃ n, U n ⊆ s) {f : β → α} (hf : ∀ {N m n : β}, N ≤ m → N ≤ n → (f m, f n) ∈ U N) : cauchy_seq f
cauchy_seq_iff_tendsto.2 begin assume s hs, rw [mem_map, mem_at_top_sets], cases hU s hs with N hN, refine ⟨(N, N), λ mn hmn, _⟩, cases mn with m n, exact hN (hf hmn.1 hmn.2) end
lemma
cauchy_seq_of_controlled
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "mem_map", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete_iff_cluster_pt {s : set α} : is_complete s ↔ ∀ l, cauchy l → l ≤ 𝓟 s → ∃ x ∈ s, cluster_pt x l
forall₃_congr $ λ l hl hls, exists₂_congr $ λ x hx, le_nhds_iff_adhp_of_cauchy hl
lemma
is_complete_iff_cluster_pt
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "cluster_pt", "exists₂_congr", "forall₃_congr", "is_complete", "le_nhds_iff_adhp_of_cauchy" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete_iff_ultrafilter {s : set α} : is_complete s ↔ ∀ l : ultrafilter α, cauchy (l : filter α) → ↑l ≤ 𝓟 s → ∃ x ∈ s, ↑l ≤ 𝓝 x
begin refine ⟨λ h l, h l, λ H, is_complete_iff_cluster_pt.2 $ λ l hl hls, _⟩, haveI := hl.1, rcases H (ultrafilter.of l) hl.ultrafilter_of ((ultrafilter.of_le l).trans hls) with ⟨x, hxs, hxl⟩, exact ⟨x, hxs, (cluster_pt.of_le_nhds hxl).mono (ultrafilter.of_le l)⟩ end
lemma
is_complete_iff_ultrafilter
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "cluster_pt.of_le_nhds", "filter", "is_complete", "ultrafilter", "ultrafilter.of", "ultrafilter.of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete_iff_ultrafilter' {s : set α} : is_complete s ↔ ∀ l : ultrafilter α, cauchy (l : filter α) → s ∈ l → ∃ x ∈ s, ↑l ≤ 𝓝 x
is_complete_iff_ultrafilter.trans $ by simp only [le_principal_iff, ultrafilter.mem_coe]
lemma
is_complete_iff_ultrafilter'
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "is_complete", "ultrafilter", "ultrafilter.mem_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete.union {s t : set α} (hs : is_complete s) (ht : is_complete t) : is_complete (s ∪ t)
begin simp only [is_complete_iff_ultrafilter', ultrafilter.union_mem_iff, or_imp_distrib] at *, exact λ l hl, ⟨λ hsl, (hs l hl hsl).imp $ λ x hx, ⟨or.inl hx.fst, hx.snd⟩, λ htl, (ht l hl htl).imp $ λ x hx, ⟨or.inr hx.fst, hx.snd⟩⟩ end
lemma
is_complete.union
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "is_complete", "is_complete_iff_ultrafilter'", "or_imp_distrib", "ultrafilter.union_mem_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete_Union_separated {ι : Sort*} {s : ι → set α} (hs : ∀ i, is_complete (s i)) {U : set (α × α)} (hU : U ∈ 𝓤 α) (hd : ∀ (i j : ι) (x ∈ s i) (y ∈ s j), (x, y) ∈ U → i = j) : is_complete (⋃ i, s i)
begin set S := ⋃ i, s i, intros l hl hls, rw le_principal_iff at hls, casesI cauchy_iff.1 hl with hl_ne hl', obtain ⟨t, htS, htl, htU⟩ : ∃ t ⊆ S, t ∈ l ∧ t ×ˢ t ⊆ U, { rcases hl' U hU with ⟨t, htl, htU⟩, exact ⟨t ∩ S, inter_subset_right _ _, inter_mem htl hls, (set.prod_mono (inter_subset_left _ _...
lemma
is_complete_Union_separated
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "filter.nonempty_of_mem", "is_complete", "set.prod_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_space (α : Type u) [uniform_space α] : Prop
(complete : ∀{f:filter α}, cauchy f → ∃x, f ≤ 𝓝 x)
class
complete_space
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "uniform_space" ]
A complete space is defined here using uniformities. A uniform space is complete if every Cauchy filter converges.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_univ {α : Type u} [uniform_space α] [complete_space α] : is_complete (univ : set α)
begin assume f hf _, rcases complete_space.complete hf with ⟨x, hx⟩, exact ⟨x, mem_univ x, hx⟩ end
lemma
complete_univ
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "is_complete", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_space.prod [uniform_space β] [complete_space α] [complete_space β] : complete_space (α × β)
{ complete := λ f hf, let ⟨x1, hx1⟩ := complete_space.complete $ hf.map uniform_continuous_fst in let ⟨x2, hx2⟩ := complete_space.complete $ hf.map uniform_continuous_snd in ⟨(x1, x2), by rw [nhds_prod_eq, filter.prod_def]; from filter.le_lift.2 (λ s hs, filter.le_lift'.2 $ λ t ht, inter_mem (...
instance
complete_space.prod
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "filter.prod_def", "nhds_prod_eq", "uniform_continuous_fst", "uniform_continuous_snd", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_space.mul_opposite [complete_space α] : complete_space αᵐᵒᵖ
{ complete := λ f hf, mul_opposite.op_surjective.exists.mpr $ let ⟨x, hx⟩ := complete_space.complete (hf.map mul_opposite.uniform_continuous_unop) in ⟨x, (map_le_iff_le_comap.mp hx).trans_eq $ mul_opposite.comap_unop_nhds _⟩}
instance
complete_space.mul_opposite
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "mul_opposite.comap_unop_nhds", "mul_opposite.uniform_continuous_unop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_space_of_is_complete_univ (h : is_complete (univ : set α)) : complete_space α
⟨λ f hf, let ⟨x, _, hx⟩ := h f hf ((@principal_univ α).symm ▸ le_top) in ⟨x, hx⟩⟩
lemma
complete_space_of_is_complete_univ
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "is_complete", "le_top" ]
If `univ` is complete, the space is a complete space
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_space_iff_is_complete_univ : complete_space α ↔ is_complete (univ : set α)
⟨@complete_univ α _, complete_space_of_is_complete_univ⟩
lemma
complete_space_iff_is_complete_univ
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "complete_univ", "is_complete" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_space_iff_ultrafilter : complete_space α ↔ ∀ l : ultrafilter α, cauchy (l : filter α) → ∃ x : α, ↑l ≤ 𝓝 x
by simp [complete_space_iff_is_complete_univ, is_complete_iff_ultrafilter]
lemma
complete_space_iff_ultrafilter
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "complete_space", "complete_space_iff_is_complete_univ", "filter", "is_complete_iff_ultrafilter", "ultrafilter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_iff_exists_le_nhds [complete_space α] {l : filter α} [ne_bot l] : cauchy l ↔ (∃x, l ≤ 𝓝 x)
⟨complete_space.complete, assume ⟨x, hx⟩, cauchy_nhds.mono hx⟩
lemma
cauchy_iff_exists_le_nhds
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "complete_space", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_map_iff_exists_tendsto [complete_space α] {l : filter β} {f : β → α} [ne_bot l] : cauchy (l.map f) ↔ (∃x, tendsto f l (𝓝 x))
cauchy_iff_exists_le_nhds
lemma
cauchy_map_iff_exists_tendsto
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "cauchy_iff_exists_le_nhds", "complete_space", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_tendsto_of_complete [semilattice_sup β] [complete_space α] {u : β → α} (H : cauchy_seq u) : ∃x, tendsto u at_top (𝓝 x)
complete_space.complete H
theorem
cauchy_seq_tendsto_of_complete
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "complete_space", "semilattice_sup" ]
A Cauchy sequence in a complete space converges
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq_tendsto_of_is_complete [semilattice_sup β] {K : set α} (h₁ : is_complete K) {u : β → α} (h₂ : ∀ n, u n ∈ K) (h₃ : cauchy_seq u) : ∃ v ∈ K, tendsto u at_top (𝓝 v)
h₁ _ h₃ $ le_principal_iff.2 $ mem_map_iff_exists_image.2 ⟨univ, univ_mem, by { simp only [image_univ], rintros _ ⟨n, rfl⟩, exact h₂ n }⟩
lemma
cauchy_seq_tendsto_of_is_complete
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "is_complete", "semilattice_sup" ]
If `K` is a complete subset, then any cauchy sequence in `K` converges to a point in `K`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy.le_nhds_Lim [complete_space α] [nonempty α] {f : filter α} (hf : cauchy f) : f ≤ 𝓝 (Lim f)
le_nhds_Lim (complete_space.complete hf)
theorem
cauchy.le_nhds_Lim
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "Lim", "cauchy", "complete_space", "filter", "le_nhds_Lim" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.tendsto_lim [semilattice_sup β] [complete_space α] [nonempty α] {u : β → α} (h : cauchy_seq u) : tendsto u at_top (𝓝 $ lim at_top u)
h.le_nhds_Lim
theorem
cauchy_seq.tendsto_lim
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "complete_space", "lim", "semilattice_sup" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed.is_complete [complete_space α] {s : set α} (h : is_closed s) : is_complete s
λ f cf fs, let ⟨x, hx⟩ := complete_space.complete cf in ⟨x, is_closed_iff_cluster_pt.mp h x (cf.left.mono (le_inf hx fs)), hx⟩
lemma
is_closed.is_complete
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "is_closed", "is_complete", "le_inf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded (s : set α) : Prop
∀d ∈ 𝓤 α, ∃t : set α, t.finite ∧ s ⊆ (⋃ y ∈ t, {x | (x, y) ∈ d})
def
totally_bounded
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[]
A set `s` is totally bounded if for every entourage `d` there is a finite set of points `t` such that every element of `s` is `d`-near to some element of `t`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded.exists_subset {s : set α} (hs : totally_bounded s) {U : set (α × α)} (hU : U ∈ 𝓤 α) : ∃ t ⊆ s, set.finite t ∧ s ⊆ ⋃ y ∈ t, {x | (x, y) ∈ U}
begin rcases comp_symm_of_uniformity hU with ⟨r, hr, rs, rU⟩, rcases hs r hr with ⟨k, fk, ks⟩, let u := k ∩ {y | ∃ x ∈ s, (x, y) ∈ r}, choose hk f hfs hfr using λ x : u, x.coe_prop, refine ⟨range f, _, _, _⟩, { exact range_subset_iff.2 hfs }, { haveI : fintype u := (fk.inter_of_left _).fintype, exact ...
theorem
totally_bounded.exists_subset
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "comp_symm_of_uniformity", "fintype", "set.finite", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded_iff_subset {s : set α} : totally_bounded s ↔ ∀d ∈ 𝓤 α, ∃t ⊆ s, set.finite t ∧ s ⊆ (⋃y∈t, {x | (x,y) ∈ d})
⟨λ H d hd, H.exists_subset hd, λ H d hd, let ⟨t, _, ht⟩ := H d hd in ⟨t, ht⟩⟩
theorem
totally_bounded_iff_subset
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "set.finite", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.totally_bounded_iff {ι} {p : ι → Prop} {U : ι → set (α × α)} (H : (𝓤 α).has_basis p U) {s : set α} : totally_bounded s ↔ ∀ i, p i → ∃ t : set α, set.finite t ∧ s ⊆ ⋃ y ∈ t, {x | (x, y) ∈ U i}
H.forall_iff $ λ U V hUV h, h.imp $ λ t ht, ⟨ht.1, ht.2.trans $ Union₂_mono $ λ x hx y hy, hUV hy⟩
lemma
filter.has_basis.totally_bounded_iff
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "set.finite", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded_of_forall_symm {s : set α} (h : ∀ V ∈ 𝓤 α, symmetric_rel V → ∃ t : set α, set.finite t ∧ s ⊆ ⋃ y ∈ t, ball y V) : totally_bounded s
uniform_space.has_basis_symmetric.totally_bounded_iff.2 $ λ V hV, by simpa only [ball_eq_of_symmetry hV.2] using h V hV.1 hV.2
lemma
totally_bounded_of_forall_symm
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "ball_eq_of_symmetry", "set.finite", "symmetric_rel", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded_subset {s₁ s₂ : set α} (hs : s₁ ⊆ s₂) (h : totally_bounded s₂) : totally_bounded s₁
assume d hd, let ⟨t, ht₁, ht₂⟩ := h d hd in ⟨t, ht₁, subset.trans hs ht₂⟩
lemma
totally_bounded_subset
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded_empty : totally_bounded (∅ : set α)
λ d hd, ⟨∅, finite_empty, empty_subset _⟩
lemma
totally_bounded_empty
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded.closure {s : set α} (h : totally_bounded s) : totally_bounded (closure s)
uniformity_has_basis_closed.totally_bounded_iff.2 $ λ V hV, let ⟨t, htf, hst⟩ := h V hV.1 in ⟨t, htf, closure_minimal hst $ is_closed_bUnion htf $ λ y hy, hV.2.preimage (continuous_id.prod_mk continuous_const)⟩
lemma
totally_bounded.closure
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "closure", "closure_minimal", "continuous_const", "is_closed_bUnion", "totally_bounded" ]
The closure of a totally bounded set is totally bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded.image [uniform_space β] {f : α → β} {s : set α} (hs : totally_bounded s) (hf : uniform_continuous f) : totally_bounded (f '' s)
assume t ht, have {p:α×α | (f p.1, f p.2) ∈ t} ∈ 𝓤 α, from hf ht, let ⟨c, hfc, hct⟩ := hs _ this in ⟨f '' c, hfc.image f, begin simp [image_subset_iff], simp [subset_def] at hct, intros x hx, simp, exact hct x hx end⟩
lemma
totally_bounded.image
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "totally_bounded", "uniform_continuous", "uniform_space" ]
The image of a totally bounded set under a uniformly continuous map is totally bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ultrafilter.cauchy_of_totally_bounded {s : set α} (f : ultrafilter α) (hs : totally_bounded s) (h : ↑f ≤ 𝓟 s) : cauchy (f : filter α)
⟨f.ne_bot', assume t ht, let ⟨t', ht'₁, ht'_symm, ht'_t⟩ := comp_symm_of_uniformity ht in let ⟨i, hi, hs_union⟩ := hs t' ht'₁ in have (⋃y∈i, {x | (x,y) ∈ t'}) ∈ f, from mem_of_superset (le_principal_iff.mp h) hs_union, have ∃y∈i, {x | (x,y) ∈ t'} ∈ f, from (ultrafilter.finite_bUnion_mem_iff hi).1 this, ...
lemma
ultrafilter.cauchy_of_totally_bounded
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "comp_rel", "comp_symm_of_uniformity", "filter", "totally_bounded", "ultrafilter", "ultrafilter.finite_bUnion_mem_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded_iff_filter {s : set α} : totally_bounded s ↔ (∀f, ne_bot f → f ≤ 𝓟 s → ∃c ≤ f, cauchy c)
begin split, { introsI H f hf hfs, exact ⟨ultrafilter.of f, ultrafilter.of_le f, (ultrafilter.of f).cauchy_of_totally_bounded H ((ultrafilter.of_le f).trans hfs)⟩ }, { intros H d hd, contrapose! H with hd_cover, set f := ⨅ t : finset α, 𝓟 (s \ ⋃ y ∈ t, {x | (x, y) ∈ d}), have : ne_bot f, ...
lemma
totally_bounded_iff_filter
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "directed_of_sup", "finset", "infi_le_of_le", "le_rfl", "totally_bounded", "ultrafilter.of", "ultrafilter.of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
totally_bounded_iff_ultrafilter {s : set α} : totally_bounded s ↔ (∀f : ultrafilter α, ↑f ≤ 𝓟 s → cauchy (f : filter α))
begin refine ⟨λ hs f, f.cauchy_of_totally_bounded hs, λ H, totally_bounded_iff_filter.2 _⟩, introsI f hf hfs, exact ⟨ultrafilter.of f, ultrafilter.of_le f, H _ ((ultrafilter.of_le f).trans hfs)⟩ end
lemma
totally_bounded_iff_ultrafilter
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy", "filter", "totally_bounded", "ultrafilter", "ultrafilter.of_le" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact_iff_totally_bounded_is_complete {s : set α} : is_compact s ↔ totally_bounded s ∧ is_complete s
⟨λ hs, ⟨totally_bounded_iff_ultrafilter.2 (λ f hf, let ⟨x, xs, fx⟩ := is_compact_iff_ultrafilter_le_nhds.1 hs f hf in cauchy_nhds.mono fx), λ f fc fs, let ⟨a, as, fa⟩ := @hs f fc.1 fs in ⟨a, as, le_nhds_of_cauchy_adhp fc fa⟩⟩, λ ⟨ht, hc⟩, is_compact_iff_ultrafilter_le_nhds.2 (λf hf, hc _ (totally_boun...
lemma
is_compact_iff_totally_bounded_is_complete
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "is_compact", "is_complete", "le_nhds_of_cauchy_adhp", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact.totally_bounded {s : set α} (h : is_compact s) : totally_bounded s
(is_compact_iff_totally_bounded_is_complete.1 h).1
lemma
is_compact.totally_bounded
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "is_compact", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact.is_complete {s : set α} (h : is_compact s) : is_complete s
(is_compact_iff_totally_bounded_is_complete.1 h).2
lemma
is_compact.is_complete
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "is_compact", "is_complete" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_of_compact {α : Type u} [uniform_space α] [compact_space α] : complete_space α
⟨λf hf, by simpa using (is_compact_iff_totally_bounded_is_complete.1 is_compact_univ).2 f hf⟩
instance
complete_of_compact
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "compact_space", "complete_space", "is_compact_univ", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact_of_totally_bounded_is_closed [complete_space α] {s : set α} (ht : totally_bounded s) (hc : is_closed s) : is_compact s
(@is_compact_iff_totally_bounded_is_complete α _ s).2 ⟨ht, hc.is_complete⟩
lemma
is_compact_of_totally_bounded_is_closed
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "complete_space", "is_closed", "is_compact", "is_compact_iff_totally_bounded_is_complete", "totally_bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cauchy_seq.totally_bounded_range {s : ℕ → α} (hs : cauchy_seq s) : totally_bounded (range s)
begin refine totally_bounded_iff_subset.2 (λ a ha, _), cases cauchy_seq_iff.1 hs a ha with n hn, refine ⟨s '' {k | k ≤ n}, image_subset_range _ _, (finite_le_nat _).image _, _⟩, rw [range_subset_iff, bUnion_image], intro m, rw [mem_Union₂], cases le_total m n with hm hm, exacts [⟨m, hm, refl_mem_uniform...
lemma
cauchy_seq.totally_bounded_range
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "cauchy_seq", "refl_mem_uniformity", "totally_bounded" ]
Every Cauchy sequence over `ℕ` is totally bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_seq_aux (n : ℕ) : {s : set α // ∃ (_ : s ∈ f), s ×ˢ s ⊆ U n }
indefinite_description _ $ (cauchy_iff.1 hf).2 (U n) (U_mem n)
def
sequentially_complete.set_seq_aux
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[]
An auxiliary sequence of sets approximating a Cauchy filter.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
set_seq (n : ℕ) : set α
⋂ m ∈ set.Iic n, (set_seq_aux hf U_mem m).val
def
sequentially_complete.set_seq
topology.uniform_space
src/topology/uniform_space/cauchy.lean
[ "topology.algebra.constructions", "topology.bases", "topology.uniform_space.basic" ]
[ "set.Iic" ]
Given a Cauchy filter `f` and a sequence `U` of entourages, `set_seq` provides an antitone sequence of sets `s n ∈ f` such that `s n ×ˢ s n ⊆ U`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83