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comap_id : @comap X X Z _ _ id = id
by { ext, simp only [continuous_id, id.def, function.comp.right_id, coe_comap] }
lemma
locally_constant.comap_id
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "continuous_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_comp [topological_space Z] (f : X → Y) (g : Y → Z) (hf : continuous f) (hg : continuous g) : @comap _ _ α _ _ f ∘ comap g = comap (g ∘ f)
by { ext, simp only [hf, hg, hg.comp hf, coe_comap] }
lemma
locally_constant.comap_comp
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "continuous", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_const (f : X → Y) (y : Y) (h : ∀ x, f x = y) : (comap f : locally_constant Y Z → locally_constant X Z) = λ g, ⟨λ x, g y, is_locally_constant.const _⟩
begin ext, rw coe_comap, { simp only [h, coe_mk, function.comp_app] }, { rw show f = λ x, y, by ext; apply h, exact continuous_const } end
lemma
locally_constant.comap_const
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "continuous_const", "is_locally_constant.const", "locally_constant" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc {X α β : Type*} [topological_space X] {g : α → β} (f : X → α) (h : locally_constant X β) (cond : g ∘ f = h) (inj : function.injective g) : locally_constant X α
{ to_fun := f, is_locally_constant := is_locally_constant.desc _ g (by { rw cond, exact h.2 }) inj }
def
locally_constant.desc
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "is_locally_constant", "is_locally_constant.desc", "locally_constant", "topological_space" ]
If a locally constant function factors through an injection, then it factors through a locally constant function.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coe_desc {X α β : Type*} [topological_space X] (f : X → α) (g : α → β) (h : locally_constant X β) (cond : g ∘ f = h) (inj : function.injective g) : ⇑(desc f h cond inj) = f
rfl
lemma
locally_constant.coe_desc
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "locally_constant", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_indicator (hU : is_clopen U) : locally_constant X R
{ to_fun := set.mul_indicator U f, is_locally_constant := begin rw is_locally_constant.iff_exists_open, rintros x, obtain ⟨V, hV, hx, h'⟩ := (is_locally_constant.iff_exists_open _).1 f.is_locally_constant x, by_cases x ∈ U, { refine ⟨U ∩ V, is_open.inter hU.1 hV, set.mem_inter h hx, _⟩, ri...
def
locally_constant.mul_indicator
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "is_clopen", "is_clopen.compl", "is_locally_constant", "is_locally_constant.iff_exists_open", "is_open.inter", "locally_constant", "set.mem_compl_iff", "set.mem_inter", "set.mem_inter_iff", "set.mul_indicator", "set.mul_indicator_of_mem" ]
Given a clopen set `U` and a locally constant function `f`, `locally_constant.mul_indicator` returns the locally constant function that is `f` on `U` and `1` otherwise.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_indicator_apply_eq_if (hU : is_clopen U) : mul_indicator f hU a = if a ∈ U then f a else 1
set.mul_indicator_apply U f a
theorem
locally_constant.mul_indicator_apply_eq_if
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "is_clopen", "set.mul_indicator_apply" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_indicator_of_mem (hU : is_clopen U) (h : a ∈ U) : f.mul_indicator hU a = f a
by{ rw mul_indicator_apply, apply set.mul_indicator_of_mem h, }
theorem
locally_constant.mul_indicator_of_mem
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "is_clopen", "set.mul_indicator_of_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_indicator_of_not_mem (hU : is_clopen U) (h : a ∉ U) : f.mul_indicator hU a = 1
by{ rw mul_indicator_apply, apply set.mul_indicator_of_not_mem h, }
theorem
locally_constant.mul_indicator_of_not_mem
topology.locally_constant
src/topology/locally_constant/basic.lean
[ "topology.subset_properties", "topology.connected", "topology.continuous_function.basic", "algebra.indicator_function", "tactic.tfae", "tactic.fin_cases" ]
[ "is_clopen", "set.mul_indicator_of_not_mem" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_lipschitz_add [add_monoid β] : Prop
( lipschitz_add : ∃ C, lipschitz_with C (λ p : β × β, p.1 + p.2) )
class
has_lipschitz_add
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "add_monoid", "lipschitz_with" ]
Class `has_lipschitz_add M` says that the addition `(+) : X × X → X` is Lipschitz jointly in the two arguments.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_lipschitz_mul [monoid β] : Prop
( lipschitz_mul : ∃ C, lipschitz_with C (λ p : β × β, p.1 * p.2) )
class
has_lipschitz_mul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "lipschitz_with", "monoid" ]
Class `has_lipschitz_mul M` says that the multiplication `(*) : X × X → X` is Lipschitz jointly in the two arguments.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_lipschitz_mul.C [_i : has_lipschitz_mul β] : ℝ≥0
classical.some _i.lipschitz_mul
def
has_lipschitz_mul.C
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_lipschitz_mul" ]
The Lipschitz constant of a monoid `β` satisfying `has_lipschitz_mul`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lipschitz_with_lipschitz_const_mul_edist [_i : has_lipschitz_mul β] : lipschitz_with (has_lipschitz_mul.C β) (λ p : β × β, p.1 * p.2)
classical.some_spec _i.lipschitz_mul
lemma
lipschitz_with_lipschitz_const_mul_edist
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_lipschitz_mul", "has_lipschitz_mul.C", "lipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lipschitz_with_lipschitz_const_mul : ∀ p q : β × β, dist (p.1 * p.2) (q.1 * q.2) ≤ (has_lipschitz_mul.C β) * dist p q
begin rw ← lipschitz_with_iff_dist_le_mul, exact lipschitz_with_lipschitz_const_mul_edist, end
lemma
lipschitz_with_lipschitz_const_mul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_lipschitz_mul.C", "lipschitz_with_iff_dist_le_mul", "lipschitz_with_lipschitz_const_mul_edist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_lipschitz_mul.has_continuous_mul : has_continuous_mul β
⟨ lipschitz_with_lipschitz_const_mul_edist.continuous ⟩
instance
has_lipschitz_mul.has_continuous_mul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_continuous_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
submonoid.has_lipschitz_mul (s : submonoid β) : has_lipschitz_mul s
{ lipschitz_mul := ⟨has_lipschitz_mul.C β, begin rintros ⟨x₁, x₂⟩ ⟨y₁, y₂⟩, convert lipschitz_with_lipschitz_const_mul_edist ⟨(x₁:β), x₂⟩ ⟨y₁, y₂⟩ using 1 end⟩ }
instance
submonoid.has_lipschitz_mul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_lipschitz_mul", "lipschitz_with_lipschitz_const_mul_edist", "submonoid" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_opposite.has_lipschitz_mul : has_lipschitz_mul βᵐᵒᵖ
{ lipschitz_mul := ⟨has_lipschitz_mul.C β, λ ⟨x₁, x₂⟩ ⟨y₁, y₂⟩, (lipschitz_with_lipschitz_const_mul_edist ⟨x₂.unop, x₁.unop⟩ ⟨y₂.unop, y₁.unop⟩).trans_eq (congr_arg _ $ max_comm _ _)⟩ }
instance
mul_opposite.has_lipschitz_mul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_lipschitz_mul", "lipschitz_with_lipschitz_const_mul_edist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
real.has_lipschitz_add : has_lipschitz_add ℝ
{ lipschitz_add := ⟨2, begin rw lipschitz_with_iff_dist_le_mul, intros p q, simp only [real.dist_eq, prod.dist_eq, prod.fst_sub, prod.snd_sub, nnreal.coe_one, nnreal.coe_bit0], convert le_trans (abs_add (p.1 - q.1) (p.2 - q.2)) _ using 2, { abel }, have := le_max_left (|p.1 - q.1|) (|p.2 -...
instance
real.has_lipschitz_add
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "abs_add", "has_lipschitz_add", "lipschitz_with_iff_dist_le_mul", "nnreal.coe_bit0", "nnreal.coe_one", "prod.dist_eq", "real.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.has_lipschitz_add : has_lipschitz_add ℝ≥0
{ lipschitz_add := ⟨has_lipschitz_add.C ℝ, begin rintros ⟨x₁, x₂⟩ ⟨y₁, y₂⟩, convert lipschitz_with_lipschitz_const_add_edist ⟨(x₁:ℝ), x₂⟩ ⟨y₁, y₂⟩ using 1 end⟩ }
instance
nnreal.has_lipschitz_add
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "has_lipschitz_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_bounded_smul : Prop
( dist_smul_pair' : ∀ x : α, ∀ y₁ y₂ : β, dist (x • y₁) (x • y₂) ≤ dist x 0 * dist y₁ y₂ ) ( dist_pair_smul' : ∀ x₁ x₂ : α, ∀ y : β, dist (x₁ • y) (x₂ • y) ≤ dist x₁ x₂ * dist y 0 )
class
has_bounded_smul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[]
Mixin typeclass on a scalar action of a metric space `α` on a metric space `β` both with distinguished points `0`, requiring compatibility of the action in the sense that `dist (x • y₁) (x • y₂) ≤ dist x 0 * dist y₁ y₂` and `dist (x₁ • y) (x₂ • y) ≤ dist x₁ x₂ * dist y 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_smul_pair (x : α) (y₁ y₂ : β) : dist (x • y₁) (x • y₂) ≤ dist x 0 * dist y₁ y₂
has_bounded_smul.dist_smul_pair' x y₁ y₂
lemma
dist_smul_pair
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pair_smul (x₁ x₂ : α) (y : β) : dist (x₁ • y) (x₂ • y) ≤ dist x₁ x₂ * dist y 0
has_bounded_smul.dist_pair_smul' x₁ x₂ y
lemma
dist_pair_smul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_bounded_smul.has_continuous_smul : has_continuous_smul α β
{ continuous_smul := begin rw metric.continuous_iff, rintros ⟨a, b⟩ ε hε, have : 0 ≤ dist a 0 := dist_nonneg, have : 0 ≤ dist b 0 := dist_nonneg, let δ : ℝ := min 1 ((dist a 0 + dist b 0 + 2)⁻¹ * ε), have hδ_pos : 0 < δ, { refine lt_min_iff.mpr ⟨by norm_num, mul_pos _ hε⟩, rw inv_pos, ...
instance
has_bounded_smul.has_continuous_smul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "dist_comm", "dist_nonneg", "dist_pair_smul", "dist_smul_pair", "dist_triangle", "has_continuous_smul", "inv_mul_lt_iff", "inv_pos", "metric.continuous_iff" ]
The typeclass `has_bounded_smul` on a metric-space scalar action implies continuity of the action.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
real.has_bounded_smul : has_bounded_smul ℝ ℝ
{ dist_smul_pair' := λ x y₁ y₂, by simpa [real.dist_eq, mul_sub] using (abs_mul x (y₁ - y₂)).le, dist_pair_smul' := λ x₁ x₂ y, by simpa [real.dist_eq, sub_mul] using (abs_mul (x₁ - x₂) y).le }
instance
real.has_bounded_smul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "abs_mul", "has_bounded_smul", "real.dist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nnreal.has_bounded_smul : has_bounded_smul ℝ≥0 ℝ≥0
{ dist_smul_pair' := λ x y₁ y₂, by convert dist_smul_pair (x:ℝ) (y₁:ℝ) y₂ using 1, dist_pair_smul' := λ x₁ x₂ y, by convert dist_pair_smul (x₁:ℝ) x₂ (y:ℝ) using 1 }
instance
nnreal.has_bounded_smul
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "dist_pair_smul", "dist_smul_pair", "has_bounded_smul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_bounded_smul.op [has_smul αᵐᵒᵖ β] [is_central_scalar α β] : has_bounded_smul αᵐᵒᵖ β
{ dist_smul_pair' := mul_opposite.rec $ λ x y₁ y₂, by simpa only [op_smul_eq_smul] using dist_smul_pair x y₁ y₂, dist_pair_smul' := mul_opposite.rec $ λ x₁, mul_opposite.rec $ λ x₂ y, by simpa only [op_smul_eq_smul] using dist_pair_smul x₁ x₂ y }
instance
has_bounded_smul.op
topology.metric_space
src/topology/metric_space/algebra.lean
[ "topology.algebra.mul_action", "topology.metric_space.lipschitz" ]
[ "dist_pair_smul", "dist_smul_pair", "has_bounded_smul", "has_smul", "is_central_scalar", "mul_opposite.rec" ]
If a scalar is central, then its right action is bounded when its left action is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
antilipschitz_with [pseudo_emetric_space α] [pseudo_emetric_space β] (K : ℝ≥0) (f : α → β)
∀ x y, edist x y ≤ K * edist (f x) (f y)
def
antilipschitz_with
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "pseudo_emetric_space" ]
We say that `f : α → β` is `antilipschitz_with K` if for any two points `x`, `y` we have `edist x y ≤ K * edist (f x) (f y)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
antilipschitz_with.edist_lt_top [pseudo_emetric_space α] [pseudo_metric_space β] {K : ℝ≥0} {f : α → β} (h : antilipschitz_with K f) (x y : α) : edist x y < ⊤
(h x y).trans_lt $ ennreal.mul_lt_top ennreal.coe_ne_top (edist_ne_top _ _)
lemma
antilipschitz_with.edist_lt_top
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "edist_ne_top", "ennreal.coe_ne_top", "ennreal.mul_lt_top", "pseudo_emetric_space", "pseudo_metric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
antilipschitz_with.edist_ne_top [pseudo_emetric_space α] [pseudo_metric_space β] {K : ℝ≥0} {f : α → β} (h : antilipschitz_with K f) (x y : α) : edist x y ≠ ⊤
(h.edist_lt_top x y).ne
lemma
antilipschitz_with.edist_ne_top
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "pseudo_emetric_space", "pseudo_metric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
antilipschitz_with_iff_le_mul_nndist : antilipschitz_with K f ↔ ∀ x y, nndist x y ≤ K * nndist (f x) (f y)
by { simp only [antilipschitz_with, edist_nndist], norm_cast }
lemma
antilipschitz_with_iff_le_mul_nndist
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "edist_nndist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
antilipschitz_with_iff_le_mul_dist : antilipschitz_with K f ↔ ∀ x y, dist x y ≤ K * dist (f x) (f y)
by { simp only [antilipschitz_with_iff_le_mul_nndist, dist_nndist], norm_cast }
lemma
antilipschitz_with_iff_le_mul_dist
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "antilipschitz_with_iff_le_mul_nndist", "dist_nndist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_le_nndist (hf : antilipschitz_with K f) (x y : α) : K⁻¹ * nndist x y ≤ nndist (f x) (f y)
by simpa only [div_eq_inv_mul] using nnreal.div_le_of_le_mul' (hf.le_mul_nndist x y)
lemma
antilipschitz_with.mul_le_nndist
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "div_eq_inv_mul", "nnreal.div_le_of_le_mul'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_le_dist (hf : antilipschitz_with K f) (x y : α) : (K⁻¹ * dist x y : ℝ) ≤ dist (f x) (f y)
by exact_mod_cast hf.mul_le_nndist x y
lemma
antilipschitz_with.mul_le_dist
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
K (hf : antilipschitz_with K f) : ℝ≥0
K
def
antilipschitz_with.K
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
Extract the constant from `hf : antilipschitz_with K f`. This is useful, e.g., if `K` is given by a long formula, and we want to reuse this value.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective {α : Type*} {β : Type*} [emetric_space α] [pseudo_emetric_space β] {K : ℝ≥0} {f : α → β} (hf : antilipschitz_with K f) : function.injective f
λ x y h, by simpa only [h, edist_self, mul_zero, edist_le_zero] using hf x y
lemma
antilipschitz_with.injective
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "edist_le_zero", "emetric_space", "mul_zero", "pseudo_emetric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mul_le_edist (hf : antilipschitz_with K f) (x y : α) : (K⁻¹ * edist x y : ℝ≥0∞) ≤ edist (f x) (f y)
begin rw [mul_comm, ← div_eq_mul_inv], exact ennreal.div_le_of_le_mul' (hf x y) end
lemma
antilipschitz_with.mul_le_edist
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "div_eq_mul_inv", "ennreal.div_le_of_le_mul'", "mul_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ediam_preimage_le (hf : antilipschitz_with K f) (s : set β) : diam (f ⁻¹' s) ≤ K * diam s
diam_le $ λ x hx y hy, (hf x y).trans $ mul_le_mul_left' (edist_le_diam_of_mem hx hy) K
lemma
antilipschitz_with.ediam_preimage_le
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "mul_le_mul_left'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
le_mul_ediam_image (hf : antilipschitz_with K f) (s : set α) : diam s ≤ K * diam (f '' s)
(diam_mono (subset_preimage_image _ _)).trans (hf.ediam_preimage_le (f '' s))
lemma
antilipschitz_with.le_mul_ediam_image
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id : antilipschitz_with 1 (id : α → α)
λ x y, by simp only [ennreal.coe_one, one_mul, id, le_refl]
lemma
antilipschitz_with.id
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "ennreal.coe_one", "one_mul" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp {Kg : ℝ≥0} {g : β → γ} (hg : antilipschitz_with Kg g) {Kf : ℝ≥0} {f : α → β} (hf : antilipschitz_with Kf f) : antilipschitz_with (Kf * Kg) (g ∘ f)
λ x y, calc edist x y ≤ Kf * edist (f x) (f y) : hf x y ... ≤ Kf * (Kg * edist (g (f x)) (g (f y))) : ennreal.mul_left_mono (hg _ _) ... = _ : by rw [ennreal.coe_mul, mul_assoc]
lemma
antilipschitz_with.comp
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "ennreal.coe_mul", "ennreal.mul_left_mono", "mul_assoc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
restrict (hf : antilipschitz_with K f) (s : set α) : antilipschitz_with K (s.restrict f)
λ x y, hf x y
lemma
antilipschitz_with.restrict
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cod_restrict (hf : antilipschitz_with K f) {s : set β} (hs : ∀ x, f x ∈ s) : antilipschitz_with K (s.cod_restrict f hs)
λ x y, hf x y
lemma
antilipschitz_with.cod_restrict
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_right_inv_on' {s : set α} (hf : antilipschitz_with K (s.restrict f)) {g : β → α} {t : set β} (g_maps : maps_to g t s) (g_inv : right_inv_on g f t) : lipschitz_with K (t.restrict g)
λ x y, by simpa only [restrict_apply, g_inv x.mem, g_inv y.mem, subtype.edist_eq, subtype.coe_mk] using hf ⟨g x, g_maps x.mem⟩ ⟨g y, g_maps y.mem⟩
lemma
antilipschitz_with.to_right_inv_on'
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "lipschitz_with", "subtype.coe_mk", "subtype.edist_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_right_inv_on (hf : antilipschitz_with K f) {g : β → α} {t : set β} (h : right_inv_on g f t) : lipschitz_with K (t.restrict g)
(hf.restrict univ).to_right_inv_on' (maps_to_univ g t) h
lemma
antilipschitz_with.to_right_inv_on
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "lipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_right_inverse (hf : antilipschitz_with K f) {g : β → α} (hg : function.right_inverse g f) : lipschitz_with K g
begin intros x y, have := hf (g x) (g y), rwa [hg x, hg y] at this end
lemma
antilipschitz_with.to_right_inverse
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "lipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_uniformity_le (hf : antilipschitz_with K f) : (𝓤 β).comap (prod.map f f) ≤ 𝓤 α
begin refine ((uniformity_basis_edist.comap _).le_basis_iff uniformity_basis_edist).2 (λ ε h₀, _), refine ⟨K⁻¹ * ε, ennreal.mul_pos (ennreal.inv_ne_zero.2 ennreal.coe_ne_top) h₀.ne', _⟩, refine λ x hx, (hf x.1 x.2).trans_lt _, rw [mul_comm, ← div_eq_mul_inv] at hx, rw mul_comm, exact ennreal.mul_lt_of_lt_di...
lemma
antilipschitz_with.comap_uniformity_le
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "div_eq_mul_inv", "ennreal.coe_ne_top", "ennreal.mul_lt_of_lt_div", "ennreal.mul_pos", "mul_comm", "uniformity_basis_edist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_inducing (hf : antilipschitz_with K f) (hfc : uniform_continuous f) : uniform_inducing f
⟨le_antisymm hf.comap_uniformity_le hfc.le_comap⟩
lemma
antilipschitz_with.uniform_inducing
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "uniform_continuous", "uniform_inducing" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_embedding {α : Type*} {β : Type*} [emetric_space α] [pseudo_emetric_space β] {K : ℝ≥0} {f : α → β} (hf : antilipschitz_with K f) (hfc : uniform_continuous f) : uniform_embedding f
⟨hf.uniform_inducing hfc, hf.injective⟩
lemma
antilipschitz_with.uniform_embedding
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "emetric_space", "pseudo_emetric_space", "uniform_continuous", "uniform_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_complete_range [complete_space α] (hf : antilipschitz_with K f) (hfc : uniform_continuous f) : is_complete (range f)
(hf.uniform_inducing hfc).is_complete_range
lemma
antilipschitz_with.is_complete_range
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "complete_space", "is_complete", "uniform_continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed_range {α β : Type*} [pseudo_emetric_space α] [emetric_space β] [complete_space α] {f : α → β} {K : ℝ≥0} (hf : antilipschitz_with K f) (hfc : uniform_continuous f) : is_closed (range f)
(hf.is_complete_range hfc).is_closed
lemma
antilipschitz_with.is_closed_range
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "complete_space", "emetric_space", "is_closed", "pseudo_emetric_space", "uniform_continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_embedding {α : Type*} {β : Type*} [emetric_space α] [emetric_space β] {K : ℝ≥0} {f : α → β} [complete_space α] (hf : antilipschitz_with K f) (hfc : uniform_continuous f) : closed_embedding f
{ closed_range := hf.is_closed_range hfc, .. (hf.uniform_embedding hfc).embedding }
lemma
antilipschitz_with.closed_embedding
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "closed_embedding", "complete_space", "embedding", "emetric_space", "uniform_continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subtype_coe (s : set α) : antilipschitz_with 1 (coe : s → α)
antilipschitz_with.id.restrict s
lemma
antilipschitz_with.subtype_coe
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_subsingleton [subsingleton α] {K : ℝ≥0} : antilipschitz_with K f
λ x y, by simp only [subsingleton.elim x y, edist_self, zero_le]
lemma
antilipschitz_with.of_subsingleton
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subsingleton {α β} [emetric_space α] [pseudo_emetric_space β] {f : α → β} (h : antilipschitz_with 0 f) : subsingleton α
⟨λ x y, edist_le_zero.1 $ (h x y).trans_eq $ zero_mul _⟩
lemma
antilipschitz_with.subsingleton
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "emetric_space", "pseudo_emetric_space", "zero_mul" ]
If `f : α → β` is `0`-antilipschitz, then `α` is a `subsingleton`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_preimage (hf : antilipschitz_with K f) {s : set β} (hs : bounded s) : bounded (f ⁻¹' s)
exists.intro (K * diam s) $ λ x hx y hy, calc dist x y ≤ K * dist (f x) (f y) : hf.le_mul_dist x y ... ≤ K * diam s : mul_le_mul_of_nonneg_left (dist_le_diam_of_mem hs hx hy) K.2
lemma
antilipschitz_with.bounded_preimage
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "mul_le_mul_of_nonneg_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_cobounded (hf : antilipschitz_with K f) : tendsto f (cobounded α) (cobounded β)
compl_surjective.forall.2 $ λ s (hs : is_bounded s), metric.is_bounded_iff.2 $ hf.bounded_preimage $ metric.is_bounded_iff.1 hs
lemma
antilipschitz_with.tendsto_cobounded
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
proper_space {α : Type*} [metric_space α] {K : ℝ≥0} {f : α → β} [proper_space α] (hK : antilipschitz_with K f) (f_cont : continuous f) (hf : function.surjective f) : proper_space β
begin apply proper_space_of_compact_closed_ball_of_le 0 (λx₀ r hr, _), let K := f ⁻¹' (closed_ball x₀ r), have A : is_closed K := is_closed_ball.preimage f_cont, have B : bounded K := hK.bounded_preimage bounded_closed_ball, have : is_compact K := is_compact_iff_is_closed_bounded.2 ⟨A, B⟩, convert this.imag...
lemma
antilipschitz_with.proper_space
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "continuous", "is_closed", "is_compact", "metric_space", "proper_space", "proper_space_of_compact_closed_ball_of_le" ]
The image of a proper space under an expanding onto map is proper.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_of_image2_left (f : α → β → γ) {K₁ : ℝ≥0} (hf : ∀ b, antilipschitz_with K₁ (λ a, f a b)) {s : set α} {t : set β} (hst : bounded (set.image2 f s t)) : bounded s ∨ bounded t
begin contrapose! hst, obtain ⟨b, hb⟩ : t.nonempty := nonempty_of_unbounded hst.2, have : ¬bounded (set.image2 f s {b}), { intro h, apply hst.1, rw set.image2_singleton_right at h, replace h := (hf b).bounded_preimage h, refine h.mono (subset_preimage_image _ _) }, exact mt (bounded.mono (imag...
lemma
antilipschitz_with.bounded_of_image2_left
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "set.image2", "set.image2_singleton_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_of_image2_right {f : α → β → γ} {K₂ : ℝ≥0} (hf : ∀ a, antilipschitz_with K₂ (f a)) {s : set α} {t : set β} (hst : bounded (set.image2 f s t)) : bounded s ∨ bounded t
or.symm $ bounded_of_image2_left (flip f) hf $ image2_swap f s t ▸ hst
lemma
antilipschitz_with.bounded_of_image2_right
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "set.image2" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lipschitz_with.to_right_inverse [pseudo_emetric_space α] [pseudo_emetric_space β] {K : ℝ≥0} {f : α → β} (hf : lipschitz_with K f) {g : β → α} (hg : function.right_inverse g f) : antilipschitz_with K g
λ x y, by simpa only [hg _] using hf (g x) (g y)
lemma
lipschitz_with.to_right_inverse
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "antilipschitz_with", "lipschitz_with", "pseudo_emetric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lipschitz_with.proper_space [pseudo_metric_space α] [metric_space β] [proper_space β] {K : ℝ≥0} {f : α ≃ₜ β} (hK : lipschitz_with K f) : proper_space α
(hK.to_right_inverse f.right_inv).proper_space f.symm.continuous f.symm.surjective
theorem
lipschitz_with.proper_space
topology.metric_space
src/topology/metric_space/antilipschitz.lean
[ "topology.metric_space.lipschitz", "topology.uniform_space.complete_separated" ]
[ "lipschitz_with", "metric_space", "proper_space", "pseudo_metric_space" ]
The preimage of a proper space under a Lipschitz homeomorphism is proper.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
baire_space (α : Type*) [topological_space α] : Prop
(baire_property : ∀ f : ℕ → set α, (∀ n, is_open (f n)) → (∀ n, dense (f n)) → dense (⋂n, f n))
class
baire_space
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "is_open", "topological_space" ]
The property `baire_space α` means that the topological space `α` has the Baire property: any countable intersection of open dense subsets is dense. Formulated here when the source space is ℕ (and subsumed below by `dense_Inter_of_open` working with any encodable source space).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
baire_category_theorem_emetric_complete [pseudo_emetric_space α] [complete_space α] : baire_space α
begin refine ⟨λ f ho hd, _⟩, let B : ℕ → ℝ≥0∞ := λn, 1/2^n, have Bpos : ∀n, 0 < B n, { intro n, simp only [B, one_div, one_mul, ennreal.inv_pos], exact pow_ne_top two_ne_top }, /- Translate the density assumption into two functions `center` and `radius` associating to any n, x, δ, δpos a center and ...
instance
baire_category_theorem_emetric_complete
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "baire_space", "cauchy_seq", "cauchy_seq_of_edist_le_geometric_two", "cauchy_seq_tendsto_of_complete", "closure", "complete_space", "ennreal.add_halves", "ennreal.half_pos", "ennreal.inv_pos", "exists_prop", "filter.eventually_ge_at_top", "le_rfl", "mem_closure_iff_nhds_basis", "nat.le_ind...
Baire theorems asserts that various topological spaces have the Baire property. Two versions of these theorems are given. The first states that complete pseudo_emetric spaces are Baire.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
baire_category_theorem_locally_compact [topological_space α] [t2_space α] [locally_compact_space α] : baire_space α
begin constructor, intros f ho hd, /- To prove that an intersection of open dense subsets is dense, prove that its intersection with any open neighbourhood `U` is dense. Define recursively a decreasing sequence `K` of compact neighbourhoods: start with some compact neighbourhood inside `U`, then at each step,...
instance
baire_category_theorem_locally_compact
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "baire_space", "exists_positive_compacts_subset", "interior", "interior_subset", "is_compact", "is_compact.is_closed", "is_compact.nonempty_Inter_of_sequence_nonempty_compact_closed", "is_open_interior", "locally_compact_space", "t2_space", "topological_space" ]
The second theorem states that locally compact spaces are Baire.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_Inter_of_open_nat {f : ℕ → set α} (ho : ∀ n, is_open (f n)) (hd : ∀ n, dense (f n)) : dense (⋂ n, f n)
baire_space.baire_property f ho hd
theorem
dense_Inter_of_open_nat
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "is_open" ]
Definition of a Baire space.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_sInter_of_open {S : set (set α)} (ho : ∀s∈S, is_open s) (hS : S.countable) (hd : ∀s∈S, dense s) : dense (⋂₀S)
begin cases S.eq_empty_or_nonempty with h h, { simp [h] }, { rcases hS.exists_eq_range h with ⟨f, hf⟩, have F : ∀n, f n ∈ S := λn, by rw hf; exact mem_range_self _, rw [hf, sInter_range], exact dense_Inter_of_open_nat (λn, ho _ (F n)) (λn, hd _ (F n)) } end
theorem
dense_sInter_of_open
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_Inter_of_open_nat", "is_open" ]
Baire theorem: a countable intersection of dense open sets is dense. Formulated here with ⋂₀.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_bInter_of_open {S : set β} {f : β → set α} (ho : ∀s∈S, is_open (f s)) (hS : S.countable) (hd : ∀s∈S, dense (f s)) : dense (⋂s∈S, f s)
begin rw ← sInter_image, apply dense_sInter_of_open, { rwa ball_image_iff }, { exact hS.image _ }, { rwa ball_image_iff } end
theorem
dense_bInter_of_open
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_sInter_of_open", "is_open" ]
Baire theorem: a countable intersection of dense open sets is dense. Formulated here with an index set which is a countable set in any type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_Inter_of_open [encodable β] {f : β → set α} (ho : ∀s, is_open (f s)) (hd : ∀s, dense (f s)) : dense (⋂s, f s)
begin rw ← sInter_range, apply dense_sInter_of_open, { rwa forall_range_iff }, { exact countable_range _ }, { rwa forall_range_iff } end
theorem
dense_Inter_of_open
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_sInter_of_open", "encodable", "is_open" ]
Baire theorem: a countable intersection of dense open sets is dense. Formulated here with an index set which is an encodable type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_residual {s : set α} : s ∈ residual α ↔ ∃ t ⊆ s, is_Gδ t ∧ dense t
begin split, { rw mem_residual_iff, rintros ⟨S, hSo, hSd, Sct, Ss⟩, refine ⟨_, Ss, ⟨_, λ t ht, hSo _ ht, Sct, rfl⟩, _⟩, exact dense_sInter_of_open hSo Sct hSd, }, rintros ⟨t, ts, ho, hd⟩, exact mem_of_superset (residual_of_dense_Gδ ho hd) ts, end
lemma
mem_residual
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_sInter_of_open", "is_Gδ", "mem_residual_iff", "residual", "residual_of_dense_Gδ" ]
A set is residual (comeagre) if and only if it includes a dense `Gδ` set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eventually_residual {p : α → Prop} : (∀ᶠ x in residual α, p x) ↔ ∃ (t : set α), is_Gδ t ∧ dense t ∧ ∀ (x : α), x ∈ t → p x
begin -- this can probably be improved... convert @mem_residual _ _ _ p, simp_rw [exists_prop, and_comm ((_ : set α) ⊆ p), and_assoc], refl, end
lemma
eventually_residual
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "exists_prop", "is_Gδ", "mem_residual", "residual" ]
A property holds on a residual (comeagre) set if and only if it holds on some dense `Gδ` set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_of_mem_residual {s : set α} (hs : s ∈ residual α) : dense s
let ⟨t, hts, _, hd⟩ := mem_residual.1 hs in hd.mono hts
lemma
dense_of_mem_residual
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "residual" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_sInter_of_Gδ {S : set (set α)} (ho : ∀s∈S, is_Gδ s) (hS : S.countable) (hd : ∀s∈S, dense s) : dense (⋂₀S)
dense_of_mem_residual ((countable_sInter_mem hS).mpr (λ s hs, residual_of_dense_Gδ (ho _ hs) (hd _ hs)))
theorem
dense_sInter_of_Gδ
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "countable_sInter_mem", "dense", "dense_of_mem_residual", "is_Gδ", "residual_of_dense_Gδ" ]
Baire theorem: a countable intersection of dense Gδ sets is dense. Formulated here with ⋂₀.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_Inter_of_Gδ [encodable β] {f : β → set α} (ho : ∀s, is_Gδ (f s)) (hd : ∀s, dense (f s)) : dense (⋂s, f s)
begin rw ← sInter_range, exact dense_sInter_of_Gδ (forall_range_iff.2 ‹_›) (countable_range _) (forall_range_iff.2 ‹_›) end
theorem
dense_Inter_of_Gδ
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_sInter_of_Gδ", "encodable", "is_Gδ" ]
Baire theorem: a countable intersection of dense Gδ sets is dense. Formulated here with an index set which is an encodable type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_bInter_of_Gδ {S : set β} {f : Π x ∈ S, set α} (ho : ∀s∈S, is_Gδ (f s ‹_›)) (hS : S.countable) (hd : ∀s∈S, dense (f s ‹_›)) : dense (⋂s∈S, f s ‹_›)
begin rw bInter_eq_Inter, haveI := hS.to_encodable, exact dense_Inter_of_Gδ (λ s, ho s s.2) (λ s, hd s s.2) end
theorem
dense_bInter_of_Gδ
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_Inter_of_Gδ", "is_Gδ" ]
Baire theorem: a countable intersection of dense Gδ sets is dense. Formulated here with an index set which is a countable set in any type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense.inter_of_Gδ {s t : set α} (hs : is_Gδ s) (ht : is_Gδ t) (hsc : dense s) (htc : dense t) : dense (s ∩ t)
begin rw [inter_eq_Inter], apply dense_Inter_of_Gδ; simp [bool.forall_bool, *] end
theorem
dense.inter_of_Gδ
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "bool.forall_bool", "dense", "dense_Inter_of_Gδ", "is_Gδ" ]
Baire theorem: the intersection of two dense Gδ sets is dense.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_Gδ.dense_Union_interior_of_closed [encodable ι] {s : set α} (hs : is_Gδ s) (hd : dense s) {f : ι → set α} (hc : ∀ i, is_closed (f i)) (hU : s ⊆ ⋃ i, f i) : dense (⋃ i, interior (f i))
begin let g := λ i, (frontier (f i))ᶜ, have hgo : ∀ i, is_open (g i), from λ i, is_closed_frontier.is_open_compl, have hgd : dense (⋂ i, g i), { refine dense_Inter_of_open hgo (λ i x, _), rw [closure_compl, interior_frontier (hc _)], exact id }, refine (hd.inter_of_Gδ hs (is_Gδ_Inter_of_open $ λ i, hg...
lemma
is_Gδ.dense_Union_interior_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "closure_compl", "dense", "dense_Inter_of_open", "encodable", "frontier", "interior", "interior_frontier", "is_Gδ", "is_Gδ_Inter_of_open", "is_closed", "is_open", "self_diff_frontier" ]
If a countable family of closed sets cover a dense `Gδ` set, then the union of their interiors is dense. Formulated here with `⋃`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_Gδ.dense_bUnion_interior_of_closed {t : set ι} {s : set α} (hs : is_Gδ s) (hd : dense s) (ht : t.countable) {f : ι → set α} (hc : ∀ i ∈ t, is_closed (f i)) (hU : s ⊆ ⋃ i ∈ t, f i) : dense (⋃ i ∈ t, interior (f i))
begin haveI := ht.to_encodable, simp only [bUnion_eq_Union, set_coe.forall'] at *, exact hs.dense_Union_interior_of_closed hd hc hU end
lemma
is_Gδ.dense_bUnion_interior_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "interior", "is_Gδ", "is_closed", "set_coe.forall'" ]
If a countable family of closed sets cover a dense `Gδ` set, then the union of their interiors is dense. Formulated here with a union over a countable set in any type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_Gδ.dense_sUnion_interior_of_closed {T : set (set α)} {s : set α} (hs : is_Gδ s) (hd : dense s) (hc : T.countable) (hc' : ∀ t ∈ T, is_closed t) (hU : s ⊆ ⋃₀ T) : dense (⋃ t ∈ T, interior t)
hs.dense_bUnion_interior_of_closed hd hc hc' $ by rwa [← sUnion_eq_bUnion]
lemma
is_Gδ.dense_sUnion_interior_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "interior", "is_Gδ", "is_closed" ]
If a countable family of closed sets cover a dense `Gδ` set, then the union of their interiors is dense. Formulated here with `⋃₀`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_bUnion_interior_of_closed {S : set β} {f : β → set α} (hc : ∀s∈S, is_closed (f s)) (hS : S.countable) (hU : (⋃s∈S, f s) = univ) : dense (⋃s∈S, interior (f s))
is_Gδ_univ.dense_bUnion_interior_of_closed dense_univ hS hc hU.ge
theorem
dense_bUnion_interior_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_univ", "interior", "is_closed" ]
Baire theorem: if countably many closed sets cover the whole space, then their interiors are dense. Formulated here with an index set which is a countable set in any type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_sUnion_interior_of_closed {S : set (set α)} (hc : ∀s∈S, is_closed s) (hS : S.countable) (hU : (⋃₀ S) = univ) : dense (⋃s∈S, interior s)
is_Gδ_univ.dense_sUnion_interior_of_closed dense_univ hS hc hU.ge
theorem
dense_sUnion_interior_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_univ", "interior", "is_closed" ]
Baire theorem: if countably many closed sets cover the whole space, then their interiors are dense. Formulated here with `⋃₀`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_Union_interior_of_closed [encodable β] {f : β → set α} (hc : ∀s, is_closed (f s)) (hU : (⋃s, f s) = univ) : dense (⋃s, interior (f s))
is_Gδ_univ.dense_Union_interior_of_closed dense_univ hc hU.ge
theorem
dense_Union_interior_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense", "dense_univ", "encodable", "interior", "is_closed" ]
Baire theorem: if countably many closed sets cover the whole space, then their interiors are dense. Formulated here with an index set which is an encodable type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_interior_of_Union_of_closed [nonempty α] [encodable β] {f : β → set α} (hc : ∀s, is_closed (f s)) (hU : (⋃s, f s) = univ) : ∃s, (interior $ f s).nonempty
by simpa using (dense_Union_interior_of_closed hc hU).nonempty
theorem
nonempty_interior_of_Union_of_closed
topology.metric_space
src/topology/metric_space/baire.lean
[ "analysis.specific_limits.basic", "topology.G_delta", "topology.sets.compacts" ]
[ "dense_Union_interior_of_closed", "encodable", "interior", "is_closed" ]
One of the most useful consequences of Baire theorem: if a countable union of closed sets covers the space, then one of the sets has nonempty interior.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniform_space_of_dist (dist : α → α → ℝ) (dist_self : ∀ x : α, dist x x = 0) (dist_comm : ∀ x y : α, dist x y = dist y x) (dist_triangle : ∀ x y z : α, dist x z ≤ dist x y + dist y z) : uniform_space α
uniform_space.of_fun dist dist_self dist_comm dist_triangle $ λ ε ε0, ⟨ε / 2, half_pos ε0, λ x hx y hy, add_halves ε ▸ add_lt_add hx hy⟩
def
uniform_space_of_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "add_halves", "dist_comm", "dist_self", "dist_triangle", "half_pos", "uniform_space", "uniform_space.of_fun" ]
Construct a uniform structure from a distance function and metric space axioms
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_iff_aux {α : Type*} (dist : α → α → ℝ) (dist_comm : ∀ x y : α, dist x y = dist y x) (dist_triangle : ∀ x y z : α, dist x z ≤ dist x y + dist y z) (s : set α) (a : α) : (∃ c, ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → dist x y ≤ c) ↔ (∃ r, ∀ ⦃x⦄, x ∈ s → dist x a ≤ r)
begin split; rintro ⟨C, hC⟩, { rcases s.eq_empty_or_nonempty with rfl | ⟨x, hx⟩, { exact ⟨0, by simp⟩ }, { exact ⟨C + dist x a, λ y hy, (dist_triangle y x a).trans (add_le_add_right (hC hy hx) _)⟩ } }, { exact ⟨C + C, λ x hx y hy, (dist_triangle x a y).trans (add_le_add (hC hx) (by...
lemma
bounded_iff_aux
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "dist_triangle" ]
This is an internal lemma used to construct a bornology from a metric in `bornology.of_dist`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bornology.of_dist {α : Type*} (dist : α → α → ℝ) (dist_self : ∀ x : α, dist x x = 0) (dist_comm : ∀ x y : α, dist x y = dist y x) (dist_triangle : ∀ x y z : α, dist x z ≤ dist x y + dist y z) : bornology α
bornology.of_bounded { s : set α | ∃ C, ∀ ⦃x⦄, x ∈ s → ∀ ⦃y⦄, y ∈ s → dist x y ≤ C } ⟨0, λ x hx y, hx.elim⟩ (λ s ⟨c, hc⟩ t h, ⟨c, λ x hx y hy, hc (h hx) (h hy)⟩) (λ s hs t ht, begin rcases s.eq_empty_or_nonempty with rfl | ⟨z, hz⟩, { exact (empty_union t).symm ▸ ht }, { simp only [λ u, bou...
def
bornology.of_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "bornology", "bornology.of_bounded", "bounded_iff_aux", "dist_comm", "dist_self", "dist_triangle" ]
Construct a bornology from a distance function and metric space axioms.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_dist (α : Type*)
(dist : α → α → ℝ)
class
has_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
The distance function (given an ambient metric space on `α`), which returns a nonnegative real number `dist x y` given `x y : α`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space.dist_nonneg' {α} {x y : α} (dist : α → α → ℝ) (dist_self : ∀ x : α, dist x x = 0) (dist_comm : ∀ x y : α, dist x y = dist y x) (dist_triangle : ∀ x y z : α, dist x z ≤ dist x y + dist y z): 0 ≤ dist x y
have 2 * dist x y ≥ 0, from calc 2 * dist x y = dist x y + dist y x : by rw [dist_comm x y, two_mul] ... ≥ 0 : by rw ← dist_self x; apply dist_triangle, nonneg_of_mul_nonneg_right this zero_lt_two
theorem
pseudo_metric_space.dist_nonneg'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "dist_self", "dist_triangle", "nonneg_of_mul_nonneg_right", "two_mul", "zero_lt_two" ]
This is an internal lemma used inside the default of `pseudo_metric_space.edist`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space.edist_dist_tac : tactic unit
tactic.intros >> `[exact (ennreal.of_real_eq_coe_nnreal _).symm <|> control_laws_tac]
def
pseudo_metric_space.edist_dist_tac
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "ennreal.of_real_eq_coe_nnreal" ]
This tactic is used to populate `pseudo_metric_space.edist_dist` when the default `edist` is used.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space (α : Type u) extends has_dist α : Type u
(dist_self : ∀ x : α, dist x x = 0) (dist_comm : ∀ x y : α, dist x y = dist y x) (dist_triangle : ∀ x y z : α, dist x z ≤ dist x y + dist y z) (edist : α → α → ℝ≥0∞ := λ x y, @coe (ℝ≥0) _ _ ⟨dist x y, pseudo_metric_space.dist_nonneg' _ ‹_› ‹_› ‹_›⟩) (edist_dist : ∀ x y : α, edist x y = ennreal.of_real (dist x y) . ...
class
pseudo_metric_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "bornology", "bornology.of_dist", "dist_comm", "dist_self", "dist_triangle", "edist_dist", "ennreal.of_real", "has_dist", "pseudo_metric_space.dist_nonneg'", "pseudo_metric_space.edist_dist_tac", "uniform_space", "uniform_space_of_dist" ]
Pseudo metric and Metric spaces A pseudo metric space is endowed with a distance for which the requirement `d(x,y)=0 → x = y` might not hold. A metric space is a pseudo metric space such that `d(x,y)=0 → x = y`. Each pseudo metric space induces a canonical `uniform_space` and hence a canonical `topological_space` This...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space.ext {α : Type*} {m m' : pseudo_metric_space α} (h : m.to_has_dist = m'.to_has_dist) : m = m'
begin unfreezingI { rcases m, rcases m' }, dsimp at h, unfreezingI { subst h }, congr, { ext x y : 2, dsimp at m_edist_dist m'_edist_dist, simp [m_edist_dist, m'_edist_dist] }, { dsimp at m_uniformity_dist m'_uniformity_dist, rw ← m'_uniformity_dist at m_uniformity_dist, exact uniform_space_...
lemma
pseudo_metric_space.ext
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "pseudo_metric_space", "uniform_space_eq" ]
Two pseudo metric space structures with the same distance function coincide.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space.to_has_edist : has_edist α
⟨pseudo_metric_space.edist⟩
instance
pseudo_metric_space.to_has_edist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "has_edist" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pseudo_metric_space.of_dist_topology {α : Type u} [topological_space α] (dist : α → α → ℝ) (dist_self : ∀ x : α, dist x x = 0) (dist_comm : ∀ x y : α, dist x y = dist y x) (dist_triangle : ∀ x y z : α, dist x z ≤ dist x y + dist y z) (H : ∀ s : set α, is_open s ↔ ∀ x ∈ s, ∃ ε > 0, ∀ y, dist x y < ε → y ∈ s) : ...
{ dist := dist, dist_self := dist_self, dist_comm := dist_comm, dist_triangle := dist_triangle, to_uniform_space := { is_open_uniformity := λ s, (H s).trans $ forall₂_congr $ λ x _, ((uniform_space.has_basis_of_fun (exists_gt (0 : ℝ)) dist _ _ _ _).comap (prod.mk x)).mem_iff.symm.trans mem_comap...
def
pseudo_metric_space.of_dist_topology
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "bornology.of_dist", "dist_comm", "dist_self", "dist_triangle", "forall₂_congr", "is_open", "is_open_uniformity", "pseudo_metric_space", "topological_space", "uniform_space.has_basis_of_fun", "uniform_space_of_dist" ]
Construct a pseudo-metric space structure whose underlying topological space structure (definitionally) agrees which a pre-existing topology which is compatible with a given distance function.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_self (x : α) : dist x x = 0
pseudo_metric_space.dist_self x
theorem
dist_self
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_comm (x y : α) : dist x y = dist y x
pseudo_metric_space.dist_comm x y
theorem
dist_comm
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
edist_dist (x y : α) : edist x y = ennreal.of_real (dist x y)
pseudo_metric_space.edist_dist x y
theorem
edist_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "ennreal.of_real" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_triangle (x y z : α) : dist x z ≤ dist x y + dist y z
pseudo_metric_space.dist_triangle x y z
theorem
dist_triangle
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_triangle_left (x y z : α) : dist x y ≤ dist z x + dist z y
by rw dist_comm z; apply dist_triangle
theorem
dist_triangle_left
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "dist_triangle" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_triangle_right (x y z : α) : dist x y ≤ dist x z + dist y z
by rw dist_comm y; apply dist_triangle
theorem
dist_triangle_right
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "dist_triangle" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_triangle4 (x y z w : α) : dist x w ≤ dist x y + dist y z + dist z w
calc dist x w ≤ dist x z + dist z w : dist_triangle x z w ... ≤ (dist x y + dist y z) + dist z w : add_le_add_right (dist_triangle x y z) _
lemma
dist_triangle4
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_triangle" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_triangle4_left (x₁ y₁ x₂ y₂ : α) : dist x₂ y₂ ≤ dist x₁ y₁ + (dist x₁ x₂ + dist y₁ y₂)
by { rw [add_left_comm, dist_comm x₁, ← add_assoc], apply dist_triangle4 }
lemma
dist_triangle4_left
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "dist_triangle4" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83