statement
stringlengths
1
2.88k
proof
stringlengths
0
13.9k
type
stringclasses
10 values
symbolic_name
stringlengths
1
131
library
stringclasses
417 values
filename
stringlengths
17
80
imports
listlengths
0
16
deps
listlengths
0
64
docstring
stringlengths
0
10.2k
source_url
stringclasses
1 value
commit
stringclasses
1 value
symmetric_rel.inter {U V : set (α × α)} (hU : symmetric_rel U) (hV : symmetric_rel V) : symmetric_rel (U ∩ V)
by rw [symmetric_rel, preimage_inter, hU.eq, hV.eq]
lemma
symmetric_rel.inter
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.core (α : Type u)
(uniformity : filter (α × α)) (refl : 𝓟 id_rel ≤ uniformity) (symm : tendsto prod.swap uniformity uniformity) (comp : uniformity.lift' (λs, s ○ s) ≤ uniformity)
structure
uniform_space.core
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "id_rel", "prod.swap", "uniformity" ]
This core description of a uniform space is outside of the type class hierarchy. It is useful for constructions of uniform spaces, when the topology is derived from the uniform space.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.core.mk' {α : Type u} (U : filter (α × α)) (refl : ∀ (r ∈ U) x, (x, x) ∈ r) (symm : ∀ r ∈ U, prod.swap ⁻¹' r ∈ U) (comp : ∀ r ∈ U, ∃ t ∈ U, t ○ t ⊆ r) : uniform_space.core α
⟨U, λ r ru, id_rel_subset.2 (refl _ ru), symm, λ r ru, let ⟨s, hs, hsr⟩ := comp _ ru in mem_of_superset (mem_lift' hs) hsr⟩
def
uniform_space.core.mk'
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "prod.swap", "uniform_space.core" ]
An alternative constructor for `uniform_space.core`. This version unfolds various `filter`-related definitions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.core.mk_of_basis {α : Type u} (B : filter_basis (α × α)) (refl : ∀ (r ∈ B) x, (x, x) ∈ r) (symm : ∀ r ∈ B, ∃ t ∈ B, t ⊆ prod.swap ⁻¹' r) (comp : ∀ r ∈ B, ∃ t ∈ B, t ○ t ⊆ r) : uniform_space.core α
{ uniformity := B.filter, refl := B.has_basis.ge_iff.mpr (λ r ru, id_rel_subset.2 $ refl _ ru), symm := (B.has_basis.tendsto_iff B.has_basis).mpr symm, comp := (has_basis.le_basis_iff (B.has_basis.lift' (monotone_id.comp_rel monotone_id)) B.has_basis).mpr comp }
def
uniform_space.core.mk_of_basis
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter_basis", "monotone_id", "prod.swap", "uniform_space.core", "uniformity" ]
Defining an `uniform_space.core` from a filter basis satisfying some uniformity-like axioms.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.core.to_topological_space {α : Type u} (u : uniform_space.core α) : topological_space α
{ is_open := λs, ∀x∈s, { p : α × α | p.1 = x → p.2 ∈ s } ∈ u.uniformity, is_open_univ := by simp; intro; exact univ_mem, is_open_inter := assume s t hs ht x ⟨xs, xt⟩, by filter_upwards [hs x xs, ht x xt]; simp {contextual := tt}, is_open_sUnion := assume s hs x ⟨t, ts, xt⟩, by filter_upwards [hs...
def
uniform_space.core.to_topological_space
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open", "is_open_sUnion", "is_open_univ", "topological_space", "uniform_space.core" ]
A uniform space generates a topological space
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.core_eq : ∀{u₁ u₂ : uniform_space.core α}, u₁.uniformity = u₂.uniformity → u₁ = u₂
| ⟨u₁, _, _, _⟩ ⟨u₂, _, _, _⟩ rfl := by congr
lemma
uniform_space.core_eq
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "uniform_space.core" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space (α : Type u) extends topological_space α, uniform_space.core α
(is_open_uniformity : ∀s, @_root_.is_open _ to_topological_space s ↔ (∀x∈s, { p : α × α | p.1 = x → p.2 ∈ s } ∈ uniformity))
class
uniform_space
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open_uniformity", "topological_space", "uniform_space.core", "uniformity" ]
A uniform space is a generalization of the "uniform" topological aspects of a metric space. It consists of a filter on `α × α` called the "uniformity", which satisfies properties analogous to the reflexivity, symmetry, and triangle properties of a metric. A metric space has a natural uniformity, and a uniform ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.mk' {α} (t : topological_space α) (c : uniform_space.core α) (is_open_uniformity : ∀s:set α, is_open s ↔ (∀x∈s, { p : α × α | p.1 = x → p.2 ∈ s } ∈ c.uniformity)) : uniform_space α
⟨c, is_open_uniformity⟩
def
uniform_space.mk'
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open", "is_open_uniformity", "topological_space", "uniform_space", "uniform_space.core" ]
Alternative constructor for `uniform_space α` when a topology is already given.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.of_core {α : Type u} (u : uniform_space.core α) : uniform_space α
{ to_core := u, to_topological_space := u.to_topological_space, is_open_uniformity := assume a, iff.rfl }
def
uniform_space.of_core
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" ]
Construct a `uniform_space` from a `uniform_space.core`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.of_core_eq {α : Type u} (u : uniform_space.core α) (t : topological_space α) (h : t = u.to_topological_space) : uniform_space α
{ to_core := u, to_topological_space := t, is_open_uniformity := assume a, h.symm ▸ iff.rfl }
def
uniform_space.of_core_eq
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open_uniformity", "topological_space", "uniform_space", "uniform_space.core" ]
Construct a `uniform_space` from a `u : uniform_space.core` and a `topological_space` structure that is equal to `u.to_topological_space`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.to_core_to_topological_space (u : uniform_space α) : u.to_core.to_topological_space = u.to_topological_space
topological_space_eq $ funext $ λ s, by rw [uniform_space.is_open_uniformity, is_open_mk]
lemma
uniform_space.to_core_to_topological_space
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open_mk", "topological_space_eq", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity (α : Type u) [uniform_space α] : filter (α × α)
(@uniform_space.to_core α _).uniformity
def
uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "uniform_space" ]
The uniformity is a filter on α × α (inferred from an ambient uniform space structure on α).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space_eq : ∀ {u₁ u₂ : uniform_space α}, 𝓤[u₁] = 𝓤[u₂] → u₁ = u₂
| (uniform_space.mk' t₁ u₁ o₁) (uniform_space.mk' t₂ u₂ o₂) h := have u₁ = u₂, from uniform_space.core_eq h, have t₁ = t₂, from topological_space_eq $ funext $ assume s, by rw [o₁, o₂]; simp [this], by simp [*]
lemma
uniform_space_eq
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "topological_space_eq", "uniform_space", "uniform_space.core_eq", "uniform_space.mk'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.of_core_eq_to_core (u : uniform_space α) (t : topological_space α) (h : t = u.to_core.to_topological_space) : uniform_space.of_core_eq u.to_core t h = u
uniform_space_eq rfl
lemma
uniform_space.of_core_eq_to_core
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "topological_space", "uniform_space", "uniform_space.of_core_eq", "uniform_space_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.replace_topology {α : Type*} [i : topological_space α] (u : uniform_space α) (h : i = u.to_topological_space) : uniform_space α
uniform_space.of_core_eq u.to_core i $ h.trans u.to_core_to_topological_space.symm
def
uniform_space.replace_topology
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "topological_space", "uniform_space", "uniform_space.of_core_eq" ]
Replace topology in a `uniform_space` instance with a propositionally (but possibly not definitionally) equal one.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.replace_topology_eq {α : Type*} [i : topological_space α] (u : uniform_space α) (h : i = u.to_topological_space) : u.replace_topology h = u
u.of_core_eq_to_core _ _
lemma
uniform_space.replace_topology_eq
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "topological_space", "uniform_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.of_fun {α β : Type*} [ordered_add_comm_monoid β] (d : α → α → β) (refl : ∀ x, d x x = 0) (symm : ∀ x y, d x y = d y x) (triangle : ∀ x y z, d x z ≤ d x y + d y z) (half : ∀ ε > (0 : β), ∃ δ > (0 : β), ∀ x < δ, ∀ y < δ, x + y < ε) : uniform_space α
uniform_space.of_core { uniformity := ⨅ r > 0, 𝓟 { x | d x.1 x.2 < r }, refl := le_infi₂ $ λ r hr, principal_mono.2 $ id_rel_subset.2 $ λ x, by simpa [refl], symm := tendsto_infi_infi $ λ r, tendsto_infi_infi $ λ _, tendsto_principal_principal.2 $ λ x hx, by rwa [mem_set_of, symm], comp := le_infi₂...
def
uniform_space.of_fun
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "le_infi₂", "ordered_add_comm_monoid", "uniform_space", "uniform_space.of_core", "uniformity" ]
Define a `uniform_space` using a "distance" function. The function can be, e.g., the distance in a (usual or extended) metric space or an absolute value on a ring.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.has_basis_of_fun {α β : Type*} [linear_ordered_add_comm_monoid β] (h₀ : ∃ x : β, 0 < x) (d : α → α → β) (refl : ∀ x, d x x = 0) (symm : ∀ x y, d x y = d y x) (triangle : ∀ x y z, d x z ≤ d x y + d y z) (half : ∀ ε > (0 : β), ∃ δ > (0 : β), ∀ x < δ, ∀ y < δ, x + y < ε) : 𝓤[uniform_space.of_fun d r...
has_basis_binfi_principal' (λ ε₁ h₁ ε₂ h₂, ⟨min ε₁ ε₂, lt_min h₁ h₂, λ _x hx, lt_of_lt_of_le hx (min_le_left _ _), λ _x hx, lt_of_lt_of_le hx (min_le_right _ _)⟩) h₀
lemma
uniform_space.has_basis_of_fun
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "linear_ordered_add_comm_monoid", "uniform_space.of_fun" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_uniformity {s : set α} : is_open s ↔ (∀x∈s, { p : α × α | p.1 = x → p.2 ∈ s } ∈ 𝓤 α)
uniform_space.is_open_uniformity s
lemma
is_open_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
refl_le_uniformity : 𝓟 id_rel ≤ 𝓤 α
(@uniform_space.to_core α _).refl
lemma
refl_le_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "id_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity.ne_bot [nonempty α] : ne_bot (𝓤 α)
diagonal_nonempty.principal_ne_bot.mono refl_le_uniformity
instance
uniformity.ne_bot
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "refl_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
refl_mem_uniformity {x : α} {s : set (α × α)} (h : s ∈ 𝓤 α) : (x, x) ∈ s
refl_le_uniformity h rfl
lemma
refl_mem_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "refl_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_uniformity_of_eq {x y : α} {s : set (α × α)} (h : s ∈ 𝓤 α) (hx : x = y) : (x, y) ∈ s
refl_le_uniformity h hx
lemma
mem_uniformity_of_eq
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "refl_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
symm_le_uniformity : map (@prod.swap α α) (𝓤 _) ≤ (𝓤 _)
(@uniform_space.to_core α _).symm
lemma
symm_le_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_le_uniformity : (𝓤 α).lift' (λs:set (α×α), s ○ s) ≤ 𝓤 α
(@uniform_space.to_core α _).comp
lemma
comp_le_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
tendsto_swap_uniformity : tendsto (@prod.swap α α) (𝓤 α) (𝓤 α)
symm_le_uniformity
lemma
tendsto_swap_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap", "symm_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_mem_uniformity_sets {s : set (α × α)} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, t ○ t ⊆ s
have s ∈ (𝓤 α).lift' (λt:set (α×α), t ○ t), from comp_le_uniformity hs, (mem_lift'_sets $ monotone_id.comp_rel monotone_id).mp this
lemma
comp_mem_uniformity_sets
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_le_uniformity", "monotone_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eventually_uniformity_iterate_comp_subset {s : set (α × α)} (hs : s ∈ 𝓤 α) (n : ℕ) : ∀ᶠ t in (𝓤 α).small_sets, ((○) t) ^[n] t ⊆ s
begin suffices : ∀ᶠ t in (𝓤 α).small_sets, t ⊆ s ∧ (((○) t) ^[n] t ⊆ s), from (eventually_and.1 this).2, induction n with n ihn generalizing s, { simpa }, rcases comp_mem_uniformity_sets hs with ⟨t, htU, hts⟩, refine (ihn htU).mono (λ U hU, _), rw [function.iterate_succ_apply'], exact ⟨hU.1.trans $ (su...
lemma
eventually_uniformity_iterate_comp_subset
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_mono", "function.iterate_succ_apply'", "refl_le_uniformity", "subset_comp_self" ]
If `s ∈ 𝓤 α`, then for any natural `n`, for a subset `t` of a sufficiently small set in `𝓤 α`, we have `t ○ t ○ ... ○ t ⊆ s` (`n` compositions).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eventually_uniformity_comp_subset {s : set (α × α)} (hs : s ∈ 𝓤 α) : ∀ᶠ t in (𝓤 α).small_sets, t ○ t ⊆ s
eventually_uniformity_iterate_comp_subset hs 1
lemma
eventually_uniformity_comp_subset
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "eventually_uniformity_iterate_comp_subset" ]
If `s ∈ 𝓤 α`, then for any natural `n`, for a subset `t` of a sufficiently small set in `𝓤 α`, we have `t ○ t ⊆ s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.uniformity_trans {l : filter β} {f₁ f₂ f₃ : β → α} (h₁₂ : tendsto (λ x, (f₁ x, f₂ x)) l (𝓤 α)) (h₂₃ : tendsto (λ x, (f₂ x, f₃ x)) l (𝓤 α)) : tendsto (λ x, (f₁ x, f₃ x)) l (𝓤 α)
begin refine le_trans (le_lift'.2 $ λ s hs, mem_map.2 _) comp_le_uniformity, filter_upwards [h₁₂ hs, h₂₃ hs] with x hx₁₂ hx₂₃ using ⟨_, hx₁₂, hx₂₃⟩, end
lemma
filter.tendsto.uniformity_trans
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_le_uniformity", "filter" ]
Relation `λ f g, tendsto (λ x, (f x, g x)) l (𝓤 α)` is transitive.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.uniformity_symm {l : filter β} {f : β → α × α} (h : tendsto f l (𝓤 α)) : tendsto (λ x, ((f x).2, (f x).1)) l (𝓤 α)
tendsto_swap_uniformity.comp h
lemma
filter.tendsto.uniformity_symm
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter" ]
Relation `λ f g, tendsto (λ x, (f x, g x)) l (𝓤 α)` is symmetric
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_diag_uniformity (f : β → α) (l : filter β) : tendsto (λ x, (f x, f x)) l (𝓤 α)
assume s hs, mem_map.2 $ univ_mem' $ λ x, refl_mem_uniformity hs
lemma
tendsto_diag_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "refl_mem_uniformity" ]
Relation `λ f g, tendsto (λ x, (f x, g x)) l (𝓤 α)` is reflexive.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_const_uniformity {a : α} {f : filter β} : tendsto (λ _, (a, a)) f (𝓤 α)
tendsto_diag_uniformity (λ _, a) f
lemma
tendsto_const_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "tendsto_diag_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
symm_of_uniformity {s : set (α × α)} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, (∀a b, (a, b) ∈ t → (b, a) ∈ t) ∧ t ⊆ s
have preimage prod.swap s ∈ 𝓤 α, from symm_le_uniformity hs, ⟨s ∩ preimage prod.swap s, inter_mem hs this, λ a b ⟨h₁, h₂⟩, ⟨h₂, h₁⟩, inter_subset_left _ _⟩
lemma
symm_of_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap", "symm_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_symm_of_uniformity {s : set (α × α)} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, (∀{a b}, (a, b) ∈ t → (b, a) ∈ t) ∧ t ○ t ⊆ s
let ⟨t, ht₁, ht₂⟩ := comp_mem_uniformity_sets hs in let ⟨t', ht', ht'₁, ht'₂⟩ := symm_of_uniformity ht₁ in ⟨t', ht', ht'₁, subset.trans (monotone_id.comp_rel monotone_id ht'₂) ht₂⟩
lemma
comp_symm_of_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_mem_uniformity_sets", "monotone_id", "symm_of_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_le_symm : 𝓤 α ≤ (@prod.swap α α) <$> 𝓤 α
by rw [map_swap_eq_comap_swap]; from map_le_iff_le_comap.1 tendsto_swap_uniformity
lemma
uniformity_le_symm
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap", "tendsto_swap_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_eq_symm : 𝓤 α = (@prod.swap α α) <$> 𝓤 α
le_antisymm uniformity_le_symm symm_le_uniformity
lemma
uniformity_eq_symm
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap", "symm_le_uniformity", "uniformity_le_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_swap_uniformity : comap (@prod.swap α α) (𝓤 α) = 𝓤 α
(congr_arg _ uniformity_eq_symm).trans $ comap_map prod.swap_injective
lemma
comap_swap_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap", "prod.swap_injective", "uniformity_eq_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
symmetrize_mem_uniformity {V : set (α × α)} (h : V ∈ 𝓤 α) : symmetrize_rel V ∈ 𝓤 α
begin apply (𝓤 α).inter_sets h, rw [← image_swap_eq_preimage_swap, uniformity_eq_symm], exact image_mem_map h, end
lemma
symmetrize_mem_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "symmetrize_rel", "uniformity_eq_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.has_basis_symmetric : (𝓤 α).has_basis (λ s : set (α × α), s ∈ 𝓤 α ∧ symmetric_rel s) id
has_basis_self.2 $ λ t t_in, ⟨symmetrize_rel t, symmetrize_mem_uniformity t_in, symmetric_symmetrize_rel t, symmetrize_rel_subset_self t⟩
lemma
uniform_space.has_basis_symmetric
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "symmetric_rel", "symmetric_symmetrize_rel", "symmetrize_mem_uniformity", "symmetrize_rel_subset_self" ]
Symmetric entourages form a basis of `𝓤 α`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_lift_le_swap {g : set (α×α) → filter β} {f : filter β} (hg : monotone g) (h : (𝓤 α).lift (λs, g (preimage prod.swap s)) ≤ f) : (𝓤 α).lift g ≤ f
calc (𝓤 α).lift g ≤ (filter.map (@prod.swap α α) $ 𝓤 α).lift g : lift_mono uniformity_le_symm le_rfl ... ≤ _ : by rw [map_lift_eq2 hg, image_swap_eq_preimage_swap]; exact h
theorem
uniformity_lift_le_swap
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "filter.map", "le_rfl", "lift", "monotone", "prod.swap", "uniformity_le_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_lift_le_comp {f : set (α×α) → filter β} (h : monotone f) : (𝓤 α).lift (λs, f (s ○ s)) ≤ (𝓤 α).lift f
calc (𝓤 α).lift (λs, f (s ○ s)) = ((𝓤 α).lift' (λs:set (α×α), s ○ s)).lift f : begin rw [lift_lift'_assoc], exact monotone_id.comp_rel monotone_id, exact h end ... ≤ (𝓤 α).lift f : lift_mono comp_le_uniformity le_rfl
lemma
uniformity_lift_le_comp
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_le_uniformity", "filter", "le_rfl", "lift", "monotone", "monotone_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_le_uniformity3 : (𝓤 α).lift' (λs:set (α×α), s ○ (s ○ s)) ≤ (𝓤 α)
calc (𝓤 α).lift' (λd, d ○ (d ○ d)) = (𝓤 α).lift (λs, (𝓤 α).lift' (λt:set(α×α), s ○ (t ○ t))) : begin rw [lift_lift'_same_eq_lift'], exact (assume x, monotone_const.comp_rel $ monotone_id.comp_rel monotone_id), exact (assume x, monotone_id.comp_rel monotone_const), end ... ≤ (𝓤 α).lift (λs, (𝓤 α...
lemma
comp_le_uniformity3
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_le_uniformity", "lift", "monotone_const", "monotone_id", "uniformity_lift_le_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_symm_mem_uniformity_sets {s : set (α × α)} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, symmetric_rel t ∧ t ○ t ⊆ s
begin obtain ⟨w, w_in, w_sub⟩ : ∃ w ∈ 𝓤 α, w ○ w ⊆ s := comp_mem_uniformity_sets hs, use [symmetrize_rel w, symmetrize_mem_uniformity w_in, symmetric_symmetrize_rel w], have : symmetrize_rel w ⊆ w := symmetrize_rel_subset_self w, calc symmetrize_rel w ○ symmetrize_rel w ⊆ w ○ w : by mono ...
lemma
comp_symm_mem_uniformity_sets
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_mem_uniformity_sets", "symmetric_rel", "symmetric_symmetrize_rel", "symmetrize_mem_uniformity", "symmetrize_rel", "symmetrize_rel_subset_self" ]
See also `comp_open_symm_mem_uniformity_sets`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subset_comp_self_of_mem_uniformity {s : set (α × α)} (h : s ∈ 𝓤 α) : s ⊆ s ○ s
subset_comp_self (refl_le_uniformity h)
lemma
subset_comp_self_of_mem_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "refl_le_uniformity", "subset_comp_self" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_comp_symm_mem_uniformity_sets {s : set (α × α)} (hs : s ∈ 𝓤 α) : ∃ t ∈ 𝓤 α, symmetric_rel t ∧ t ○ t ○ t ⊆ s
begin rcases comp_symm_mem_uniformity_sets hs with ⟨w, w_in, w_symm, w_sub⟩, rcases comp_symm_mem_uniformity_sets w_in with ⟨t, t_in, t_symm, t_sub⟩, use [t, t_in, t_symm], have : t ⊆ t ○ t := subset_comp_self_of_mem_uniformity t_in, calc t ○ t ○ t ⊆ w ○ t : by mono ... ⊆ w ○ (t ○ t) : by mon...
lemma
comp_comp_symm_mem_uniformity_sets
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_symm_mem_uniformity_sets", "subset_comp_self_of_mem_uniformity", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.ball (x : β) (V : set (β × β)) : set β
(prod.mk x) ⁻¹' V
def
uniform_space.ball
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[]
The ball around `(x : β)` with respect to `(V : set (β × β))`. Intended to be used for `V ∈ 𝓤 β`, but this is not needed for the definition. Recovers the notions of metric space ball when `V = {p | dist p.1 p.2 < r }`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.mem_ball_self (x : α) {V : set (α × α)} (hV : V ∈ 𝓤 α) : x ∈ ball x V
refl_mem_uniformity hV
lemma
uniform_space.mem_ball_self
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "refl_mem_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_ball_comp {V W : set (β × β)} {x y z} (h : y ∈ ball x V) (h' : z ∈ ball y W) : z ∈ ball x (V ○ W)
prod_mk_mem_comp_rel h h'
lemma
mem_ball_comp
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod_mk_mem_comp_rel" ]
The triangle inequality for `uniform_space.ball`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_subset_of_comp_subset {V W : set (β × β)} {x y} (h : x ∈ ball y W) (h' : W ○ W ⊆ V) : ball x W ⊆ ball y V
λ z z_in, h' (mem_ball_comp h z_in)
lemma
ball_subset_of_comp_subset
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_ball_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_mono {V W : set (β × β)} (h : V ⊆ W) (x : β) : ball x V ⊆ ball x W
preimage_mono h
lemma
ball_mono
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
ball_inter (x : β) (V W : set (β × β)) : ball x (V ∩ W) = ball x V ∩ ball x W
preimage_inter
lemma
ball_inter
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
ball_inter_left (x : β) (V W : set (β × β)) : ball x (V ∩ W) ⊆ ball x V
ball_mono (inter_subset_left V W) x
lemma
ball_inter_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_inter_right (x : β) (V W : set (β × β)) : ball x (V ∩ W) ⊆ ball x W
ball_mono (inter_subset_right V W) x
lemma
ball_inter_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_ball_symmetry {V : set (β × β)} (hV : symmetric_rel V) {x y} : x ∈ ball y V ↔ y ∈ ball x V
show (x, y) ∈ prod.swap ⁻¹' V ↔ (x, y) ∈ V, by { unfold symmetric_rel at hV, rw hV }
lemma
mem_ball_symmetry
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "prod.swap", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ball_eq_of_symmetry {V : set (β × β)} (hV : symmetric_rel V) {x} : ball x V = {y | (y, x) ∈ V}
by { ext y, rw mem_ball_symmetry hV, exact iff.rfl }
lemma
ball_eq_of_symmetry
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_ball_symmetry", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_comp_of_mem_ball {V W : set (β × β)} {x y z : β} (hV : symmetric_rel V) (hx : x ∈ ball z V) (hy : y ∈ ball z W) : (x, y) ∈ V ○ W
begin rw mem_ball_symmetry hV at hx, exact ⟨z, hx, hy⟩ end
lemma
mem_comp_of_mem_ball
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_ball_symmetry", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.is_open_ball (x : α) {V : set (α × α)} (hV : is_open V) : is_open (ball x V)
hV.preimage $ continuous_const.prod_mk continuous_id
lemma
uniform_space.is_open_ball
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "continuous_id", "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_comp_comp {V W M : set (β × β)} (hW' : symmetric_rel W) {p : β × β} : p ∈ V ○ M ○ W ↔ ((ball p.1 V ×ˢ ball p.2 W) ∩ M).nonempty
begin cases p with x y, split, { rintros ⟨z, ⟨w, hpw, hwz⟩, hzy⟩, exact ⟨(w, z), ⟨hpw, by rwa mem_ball_symmetry hW'⟩, hwz⟩, }, { rintro ⟨⟨w, z⟩, ⟨w_in, z_in⟩, hwz⟩, rwa mem_ball_symmetry hW' at z_in, use [z, w] ; tauto }, end
lemma
mem_comp_comp
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_ball_symmetry", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nhds_uniformity_iff_right {x : α} {s : set α} : s ∈ 𝓝 x ↔ {p : α × α | p.1 = x → p.2 ∈ s} ∈ 𝓤 α
begin refine ⟨_, λ hs, _⟩, { simp only [mem_nhds_iff, is_open_uniformity, and_imp, exists_imp_distrib], intros t ts ht xt, filter_upwards [ht x xt] using λ y h eq, ts (h eq) }, { refine mem_nhds_iff.mpr ⟨{x | {p : α × α | p.1 = x → p.2 ∈ s} ∈ 𝓤 α}, _, _, hs⟩, { exact λ y hy, refl_mem_uniformity hy rf...
lemma
mem_nhds_uniformity_iff_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "and_imp", "comp_mem_uniformity_sets", "exists_imp_distrib", "is_open_uniformity", "mem_nhds_iff", "refl_mem_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nhds_uniformity_iff_left {x : α} {s : set α} : s ∈ 𝓝 x ↔ {p : α × α | p.2 = x → p.1 ∈ s} ∈ 𝓤 α
by { rw [uniformity_eq_symm, mem_nhds_uniformity_iff_right], refl }
lemma
mem_nhds_uniformity_iff_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_nhds_uniformity_iff_right", "uniformity_eq_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_eq_comap_uniformity {x : α} : 𝓝 x = (𝓤 α).comap (prod.mk x)
by { ext s, rw [mem_nhds_uniformity_iff_right, mem_comap_prod_mk] }
lemma
nhds_eq_comap_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_nhds_uniformity_iff_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_iff_ball_subset {s : set α} : is_open s ↔ ∀ x ∈ s, ∃ V ∈ 𝓤 α, ball x V ⊆ s
begin simp_rw [is_open_iff_mem_nhds, nhds_eq_comap_uniformity], exact iff.rfl, end
lemma
is_open_iff_ball_subset
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open", "is_open_iff_mem_nhds", "nhds_eq_comap_uniformity" ]
See also `is_open_iff_open_ball_subset`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_basis_uniformity' {p : ι → Prop} {s : ι → set (α × α)} (h : (𝓤 α).has_basis p s) {x : α} : (𝓝 x).has_basis p (λ i, ball x (s i))
by { rw [nhds_eq_comap_uniformity], exact h.comap (prod.mk x) }
lemma
nhds_basis_uniformity'
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_basis_uniformity {p : ι → Prop} {s : ι → set (α × α)} (h : (𝓤 α).has_basis p s) {x : α} : (𝓝 x).has_basis p (λ i, {y | (y, x) ∈ s i})
begin replace h := h.comap prod.swap, rw [← map_swap_eq_comap_swap, ← uniformity_eq_symm] at h, exact nhds_basis_uniformity' h end
lemma
nhds_basis_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_basis_uniformity'", "prod.swap", "uniformity_eq_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_eq_comap_uniformity' {x : α} : 𝓝 x = (𝓤 α).comap (λ y, (y, x))
(nhds_basis_uniformity (𝓤 α).basis_sets).eq_of_same_basis $ (𝓤 α).basis_sets.comap _
lemma
nhds_eq_comap_uniformity'
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_basis_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.mem_nhds_iff {x : α} {s : set α} : s ∈ 𝓝 x ↔ ∃ V ∈ 𝓤 α, ball x V ⊆ s
begin rw [nhds_eq_comap_uniformity, mem_comap], exact iff.rfl, end
lemma
uniform_space.mem_nhds_iff
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.ball_mem_nhds (x : α) ⦃V : set (α × α)⦄ (V_in : V ∈ 𝓤 α) : ball x V ∈ 𝓝 x
begin rw uniform_space.mem_nhds_iff, exact ⟨V, V_in, subset.refl _⟩ end
lemma
uniform_space.ball_mem_nhds
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "uniform_space.mem_nhds_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.mem_nhds_iff_symm {x : α} {s : set α} : s ∈ 𝓝 x ↔ ∃ V ∈ 𝓤 α, symmetric_rel V ∧ ball x V ⊆ s
begin rw uniform_space.mem_nhds_iff, split, { rintros ⟨V, V_in, V_sub⟩, use [symmetrize_rel V, symmetrize_mem_uniformity V_in, symmetric_symmetrize_rel V], exact subset.trans (ball_mono (symmetrize_rel_subset_self V) x) V_sub }, { rintros ⟨V, V_in, V_symm, V_sub⟩, exact ⟨V, V_in, V_sub⟩ } end
lemma
uniform_space.mem_nhds_iff_symm
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_mono", "symmetric_rel", "symmetric_symmetrize_rel", "symmetrize_mem_uniformity", "symmetrize_rel", "symmetrize_rel_subset_self", "uniform_space.mem_nhds_iff" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.has_basis_nhds (x : α) : has_basis (𝓝 x) (λ s : set (α × α), s ∈ 𝓤 α ∧ symmetric_rel s) (λ s, ball x s)
⟨λ t, by simp [uniform_space.mem_nhds_iff_symm, and_assoc]⟩
lemma
uniform_space.has_basis_nhds
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "symmetric_rel", "uniform_space.mem_nhds_iff_symm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.mem_closure_iff_symm_ball {s : set α} {x} : x ∈ closure s ↔ ∀ {V}, V ∈ 𝓤 α → symmetric_rel V → (s ∩ ball x V).nonempty
by simp [mem_closure_iff_nhds_basis (has_basis_nhds x), set.nonempty]
lemma
uniform_space.mem_closure_iff_symm_ball
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure", "mem_closure_iff_nhds_basis", "set.nonempty", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.mem_closure_iff_ball {s : set α} {x} : x ∈ closure s ↔ ∀ {V}, V ∈ 𝓤 α → (ball x V ∩ s).nonempty
by simp [mem_closure_iff_nhds_basis' (nhds_basis_uniformity' (𝓤 α).basis_sets)]
lemma
uniform_space.mem_closure_iff_ball
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure", "mem_closure_iff_nhds_basis'", "nhds_basis_uniformity'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space.has_basis_nhds_prod (x y : α) : has_basis (𝓝 (x, y)) (λ s, s ∈ 𝓤 α ∧ symmetric_rel s) $ λ s, ball x s ×ˢ ball y s
begin rw nhds_prod_eq, apply (has_basis_nhds x).prod_same_index (has_basis_nhds y), rintro U V ⟨U_in, U_symm⟩ ⟨V_in, V_symm⟩, exact ⟨U ∩ V, ⟨(𝓤 α).inter_sets U_in V_in, U_symm.inter V_symm⟩, ball_inter_left x U V, ball_inter_right y U V⟩, end
lemma
uniform_space.has_basis_nhds_prod
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_inter_left", "ball_inter_right", "nhds_prod_eq", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_eq_uniformity {x : α} : 𝓝 x = (𝓤 α).lift' (ball x)
(nhds_basis_uniformity' (𝓤 α).basis_sets).eq_binfi
lemma
nhds_eq_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_basis_uniformity'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_eq_uniformity' {x : α} : 𝓝 x = (𝓤 α).lift' (λ s, {y | (y, x) ∈ s})
(nhds_basis_uniformity (𝓤 α).basis_sets).eq_binfi
lemma
nhds_eq_uniformity'
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_basis_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nhds_left (x : α) {s : set (α×α)} (h : s ∈ 𝓤 α) : {y : α | (x, y) ∈ s} ∈ 𝓝 x
ball_mem_nhds x h
lemma
mem_nhds_left
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
mem_nhds_right (y : α) {s : set (α×α)} (h : s ∈ 𝓤 α) : {x : α | (x, y) ∈ s} ∈ 𝓝 y
mem_nhds_left _ (symm_le_uniformity h)
lemma
mem_nhds_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_nhds_left", "symm_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_mem_nhds_ball_subset_of_mem_nhds {a : α} {U : set α} (h : U ∈ 𝓝 a) : ∃ (V ∈ 𝓝 a) (t ∈ 𝓤 α), ∀ a' ∈ V, uniform_space.ball a' t ⊆ U
let ⟨t, ht, htU⟩ := comp_mem_uniformity_sets (mem_nhds_uniformity_iff_right.1 h) in ⟨_, mem_nhds_left a ht, t, ht, λ a₁ h₁ a₂ h₂, @htU (a, a₂) ⟨a₁, h₁, h₂⟩ rfl⟩
lemma
exists_mem_nhds_ball_subset_of_mem_nhds
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_mem_uniformity_sets", "mem_nhds_left", "uniform_space.ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact.nhds_set_basis_uniformity {p : ι → Prop} {s : ι → set (α × α)} (hU : (𝓤 α).has_basis p s) {K : set α} (hK : is_compact K) : (𝓝ˢ K).has_basis p (λ i, ⋃ x ∈ K, ball x (s i))
begin refine ⟨λ U, _⟩, simp only [mem_nhds_set_iff_forall, (nhds_basis_uniformity' hU).mem_iff, Union₂_subset_iff], refine ⟨λ H, _, λ ⟨i, hpi, hi⟩ x hx, ⟨i, hpi, hi x hx⟩⟩, replace H : ∀ x ∈ K, ∃ i : {i // p i}, ball x (s i ○ s i) ⊆ U, { intros x hx, rcases H x hx with ⟨i, hpi, hi⟩, rcases comp_mem_un...
lemma
is_compact.nhds_set_basis_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_mono", "comp_mem_uniformity_sets", "comp_rel_mono", "is_compact", "mem_nhds_set_iff_forall", "nhds_basis_uniformity'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
disjoint.exists_uniform_thickening {A B : set α} (hA : is_compact A) (hB : is_closed B) (h : disjoint A B) : ∃ V ∈ 𝓤 α, disjoint (⋃ x ∈ A, ball x V) (⋃ x ∈ B, ball x V)
begin have : Bᶜ ∈ 𝓝ˢ A := hB.is_open_compl.mem_nhds_set.mpr h.le_compl_right, rw (hA.nhds_set_basis_uniformity (filter.basis_sets _)).mem_iff at this, rcases this with ⟨U, hU, hUAB⟩, rcases comp_symm_mem_uniformity_sets hU with ⟨V, hV, hVsymm, hVU⟩, refine ⟨V, hV, set.disjoint_left.mpr $ λ x, _⟩, simp only...
lemma
disjoint.exists_uniform_thickening
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_symm_mem_uniformity_sets", "disjoint", "filter.basis_sets", "is_closed", "is_compact", "mem_ball_symmetry", "mem_comp_of_mem_ball" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
disjoint.exists_uniform_thickening_of_basis {p : ι → Prop} {s : ι → set (α × α)} (hU : (𝓤 α).has_basis p s) {A B : set α} (hA : is_compact A) (hB : is_closed B) (h : disjoint A B) : ∃ i, p i ∧ disjoint (⋃ x ∈ A, ball x (s i)) (⋃ x ∈ B, ball x (s i))
begin rcases h.exists_uniform_thickening hA hB with ⟨V, hV, hVAB⟩, rcases hU.mem_iff.1 hV with ⟨i, hi, hiV⟩, exact ⟨i, hi, hVAB.mono (Union₂_mono $ λ a _, ball_mono hiV a) (Union₂_mono $ λ b _, ball_mono hiV b)⟩, end
lemma
disjoint.exists_uniform_thickening_of_basis
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "ball_mono", "disjoint", "is_closed", "is_compact" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_right_nhds_uniformity {a : α} : tendsto (λa', (a', a)) (𝓝 a) (𝓤 α)
assume s, mem_nhds_right a
lemma
tendsto_right_nhds_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_nhds_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_left_nhds_uniformity {a : α} : tendsto (λa', (a, a')) (𝓝 a) (𝓤 α)
assume s, mem_nhds_left a
lemma
tendsto_left_nhds_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "mem_nhds_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_nhds_left {x : α} {g : set α → filter β} (hg : monotone g) : (𝓝 x).lift g = (𝓤 α).lift (λs:set (α×α), g (ball x s))
by { rw [nhds_eq_comap_uniformity, comap_lift_eq2 hg], refl }
lemma
lift_nhds_left
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "lift", "monotone", "nhds_eq_comap_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_nhds_right {x : α} {g : set α → filter β} (hg : monotone g) : (𝓝 x).lift g = (𝓤 α).lift (λs:set (α×α), g {y | (y, x) ∈ s})
by { rw [nhds_eq_comap_uniformity', comap_lift_eq2 hg], refl }
lemma
lift_nhds_right
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "filter", "lift", "monotone", "nhds_eq_comap_uniformity'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_nhds_eq_uniformity_uniformity_prod {a b : α} : 𝓝 a ×ᶠ 𝓝 b = (𝓤 α).lift (λs:set (α×α), (𝓤 α).lift' (λt:set (α×α), {y : α | (y, a) ∈ s} ×ˢ {y : α | (b, y) ∈ t}))
begin rw [nhds_eq_uniformity', nhds_eq_uniformity, prod_lift'_lift'], exacts [rfl, monotone_preimage, monotone_preimage] end
lemma
nhds_nhds_eq_uniformity_uniformity_prod
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "lift", "nhds_eq_uniformity", "nhds_eq_uniformity'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_eq_uniformity_prod {a b : α} : 𝓝 (a, b) = (𝓤 α).lift' (λs:set (α×α), {y : α | (y, a) ∈ s} ×ˢ {y : α | (b, y) ∈ s})
begin rw [nhds_prod_eq, nhds_nhds_eq_uniformity_uniformity_prod, lift_lift'_same_eq_lift'], { intro s, exact monotone_const.set_prod monotone_preimage }, { intro t, exact monotone_preimage.set_prod monotone_const } end
lemma
nhds_eq_uniformity_prod
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "monotone_const", "nhds_nhds_eq_uniformity_uniformity_prod", "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhdset_of_mem_uniformity {d : set (α×α)} (s : set (α×α)) (hd : d ∈ 𝓤 α) : ∃(t : set (α×α)), is_open t ∧ s ⊆ t ∧ t ⊆ {p | ∃x y, (p.1, x) ∈ d ∧ (x, y) ∈ s ∧ (y, p.2) ∈ d}
let cl_d := {p:α×α | ∃x y, (p.1, x) ∈ d ∧ (x, y) ∈ s ∧ (y, p.2) ∈ d} in have ∀p ∈ s, ∃t ⊆ cl_d, is_open t ∧ p ∈ t, from assume ⟨x, y⟩ hp, _root_.mem_nhds_iff.mp $ show cl_d ∈ 𝓝 (x, y), begin rw [nhds_eq_uniformity_prod, mem_lift'_sets], exact ⟨d, hd, assume ⟨a, b⟩ ⟨ha, hb⟩, ⟨x, y, ha, hp, hb⟩⟩, exact...
lemma
nhdset_of_mem_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_open", "is_open_Union", "nhds_eq_uniformity_prod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_le_uniformity (x : α) : 𝓝 (x, x) ≤ 𝓤 α
begin intros V V_in, rcases comp_symm_mem_uniformity_sets V_in with ⟨w, w_in, w_symm, w_sub⟩, have : ball x w ×ˢ ball x w ∈ 𝓝 (x, x), { rw nhds_prod_eq, exact prod_mem_prod (ball_mem_nhds x w_in) (ball_mem_nhds x w_in) }, apply mem_of_superset this, rintros ⟨u, v⟩ ⟨u_in, v_in⟩, exact w_sub (mem_comp_...
lemma
nhds_le_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_symm_mem_uniformity_sets", "mem_comp_of_mem_ball", "nhds_prod_eq" ]
Entourages are neighborhoods of the diagonal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
supr_nhds_le_uniformity : (⨆ x : α, 𝓝 (x, x)) ≤ 𝓤 α
supr_le nhds_le_uniformity
lemma
supr_nhds_le_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_le_uniformity", "supr_le" ]
Entourages are neighborhoods of the diagonal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_set_diagonal_le_uniformity : 𝓝ˢ (diagonal α) ≤ 𝓤 α
(nhds_set_diagonal α).trans_le supr_nhds_le_uniformity
lemma
nhds_set_diagonal_le_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "nhds_set_diagonal", "supr_nhds_le_uniformity" ]
Entourages are neighborhoods of the diagonal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_eq_uniformity (s : set $ α × α) : closure s = ⋂ V ∈ {V | V ∈ 𝓤 α ∧ symmetric_rel V}, V ○ s ○ V
begin ext ⟨x, y⟩, simp only [mem_closure_iff_nhds_basis (uniform_space.has_basis_nhds_prod x y), mem_Inter, mem_set_of_eq, and_imp, mem_comp_comp, exists_prop, ← mem_inter_iff, inter_comm, set.nonempty] { contextual := tt } end
lemma
closure_eq_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "and_imp", "closure", "exists_prop", "mem_closure_iff_nhds_basis", "mem_comp_comp", "set.nonempty", "symmetric_rel", "uniform_space.has_basis_nhds_prod" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_has_basis_closed : has_basis (𝓤 α) (λ V : set (α × α), V ∈ 𝓤 α ∧ is_closed V) id
begin refine filter.has_basis_self.2 (λ t h, _), rcases comp_comp_symm_mem_uniformity_sets h with ⟨w, w_in, w_symm, r⟩, refine ⟨closure w, mem_of_superset w_in subset_closure, is_closed_closure, _⟩, refine subset.trans _ r, rw closure_eq_uniformity, apply Inter_subset_of_subset, apply Inter_subset, exac...
lemma
uniformity_has_basis_closed
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure_eq_uniformity", "comp_comp_symm_mem_uniformity_sets", "is_closed", "is_closed_closure", "subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_eq_uniformity_closure : 𝓤 α = (𝓤 α).lift' closure
eq.symm $ uniformity_has_basis_closed.lift'_closure_eq_self $ λ _, and.right
lemma
uniformity_eq_uniformity_closure
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.uniformity_closure {p : ι → Prop} {U : ι → set (α × α)} (h : (𝓤 α).has_basis p U) : (𝓤 α).has_basis p (λ i, closure (U i))
(@uniformity_eq_uniformity_closure α _).symm ▸ h.lift'_closure
lemma
filter.has_basis.uniformity_closure
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure", "uniformity_eq_uniformity_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_has_basis_closure : has_basis (𝓤 α) (λ V : set (α × α), V ∈ 𝓤 α) closure
(𝓤 α).basis_sets.uniformity_closure
lemma
uniformity_has_basis_closure
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure" ]
Closed entourages form a basis of the uniformity filter.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_eq_inter_uniformity {t : set (α×α)} : closure t = (⋂ d ∈ 𝓤 α, d ○ (t ○ d))
calc closure t = ⋂ V (hV : V ∈ 𝓤 α ∧ symmetric_rel V), V ○ t ○ V : closure_eq_uniformity t ... = ⋂ V ∈ 𝓤 α, V ○ t ○ V : eq.symm $ uniform_space.has_basis_symmetric.bInter_mem $ λ V₁ V₂ hV, comp_rel_mono (comp_rel_mono hV subset.rfl) hV ... = ⋂ V ∈ 𝓤 α, V ○ (t ○ V) : by simp only [comp_rel_assoc]
lemma
closure_eq_inter_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "closure", "closure_eq_uniformity", "comp_rel_assoc", "comp_rel_mono", "symmetric_rel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniformity_eq_uniformity_interior : 𝓤 α = (𝓤 α).lift' interior
le_antisymm (le_infi $ assume d, le_infi $ assume hd, let ⟨s, hs, hs_comp⟩ := (mem_lift'_sets $ monotone_id.comp_rel $ monotone_id.comp_rel monotone_id).mp (comp_le_uniformity3 hd) in let ⟨t, ht, hst, ht_comp⟩ := nhdset_of_mem_uniformity s hs in have s ⊆ interior d, from calc s ⊆ t : h...
lemma
uniformity_eq_uniformity_interior
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "comp_le_uniformity3", "interior", "interior_subset", "le_infi", "monotone_id", "nhdset_of_mem_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
interior_mem_uniformity {s : set (α × α)} (hs : s ∈ 𝓤 α) : interior s ∈ 𝓤 α
by rw [uniformity_eq_uniformity_interior]; exact mem_lift' hs
lemma
interior_mem_uniformity
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "interior", "uniformity_eq_uniformity_interior" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_uniformity_is_closed {s : set (α×α)} (h : s ∈ 𝓤 α) : ∃t ∈ 𝓤 α, is_closed t ∧ t ⊆ s
let ⟨t, ⟨ht_mem, htc⟩, hts⟩ := uniformity_has_basis_closed.mem_iff.1 h in ⟨t, ht_mem, htc, hts⟩
lemma
mem_uniformity_is_closed
topology.uniform_space
src/topology/uniform_space/basic.lean
[ "order.filter.small_sets", "topology.subset_properties", "topology.nhds_set" ]
[ "is_closed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83