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tendsto_dist_left_cocompact_at_top [proper_space α] (x : α) : tendsto (dist x) (cocompact α) at_top
by simpa only [dist_comm] using tendsto_dist_right_cocompact_at_top x
lemma
tendsto_dist_left_cocompact_at_top
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_comm", "proper_space", "tendsto_dist_right_cocompact_at_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
proper_space_of_compact_closed_ball_of_le (R : ℝ) (h : ∀x:α, ∀r, R ≤ r → is_compact (closed_ball x r)) : proper_space α
⟨begin assume x r, by_cases hr : R ≤ r, { exact h x r hr }, { have : closed_ball x r = closed_ball x R ∩ closed_ball x r, { symmetry, apply inter_eq_self_of_subset_right, exact closed_ball_subset_closed_ball (le_of_lt (not_le.1 hr)) }, rw this, exact (h x R le_rfl).inter_right is_closed_...
lemma
proper_space_of_compact_closed_ball_of_le
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact", "le_rfl", "proper_space" ]
If all closed balls of large enough radius are compact, then the space is proper. Especially useful when the lower bound for the radius is 0.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
proper_of_compact [compact_space α] : proper_space α
⟨assume x r, is_closed_ball.is_compact⟩
instance
proper_of_compact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "compact_space", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
locally_compact_of_proper [proper_space α] : locally_compact_space α
locally_compact_space_of_has_basis (λ x, nhds_basis_closed_ball) $ λ x ε ε0, is_compact_closed_ball _ _
instance
locally_compact_of_proper
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "locally_compact_space", "locally_compact_space_of_has_basis", "proper_space" ]
A proper space is locally compact
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
complete_of_proper [proper_space α] : complete_space α
⟨begin intros f hf, /- We want to show that the Cauchy filter `f` is converging. It suffices to find a closed ball (therefore compact by properness) where it is nontrivial. -/ obtain ⟨t, t_fset, ht⟩ : ∃ t ∈ f, ∀ x y ∈ t, dist x y < 1 := (metric.cauchy_iff.1 hf).2 1 zero_lt_one, rcases hf.1.nonempty_of_mem...
instance
complete_of_proper
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "complete_space", "proper_space", "zero_lt_one" ]
A proper space is complete
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_proper_space {α : Type*} {β : Type*} [pseudo_metric_space α] [pseudo_metric_space β] [proper_space α] [proper_space β] : proper_space (α × β)
{ is_compact_closed_ball := begin rintros ⟨x, y⟩ r, rw ← closed_ball_prod_same x y, apply (is_compact_closed_ball x r).prod (is_compact_closed_ball y r), end }
instance
prod_proper_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closed_ball_prod_same", "proper_space", "pseudo_metric_space" ]
A binary product of proper spaces is proper.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pi_proper_space {π : β → Type*} [fintype β] [∀b, pseudo_metric_space (π b)] [h : ∀b, proper_space (π b)] : proper_space (Πb, π b)
begin refine proper_space_of_compact_closed_ball_of_le 0 (λx r hr, _), rw closed_ball_pi _ hr, apply is_compact_univ_pi (λb, _), apply (h b).is_compact_closed_ball end
instance
pi_proper_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closed_ball_pi", "fintype", "is_compact_univ_pi", "proper_space", "proper_space_of_compact_closed_ball_of_le", "pseudo_metric_space" ]
A finite product of proper spaces is proper.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_pos_lt_subset_ball (hr : 0 < r) (hs : is_closed s) (h : s ⊆ ball x r) : ∃ r' ∈ Ioo 0 r, s ⊆ ball x r'
begin unfreezingI { rcases eq_empty_or_nonempty s with rfl|hne }, { exact ⟨r / 2, ⟨half_pos hr, half_lt_self hr⟩, empty_subset _⟩ }, have : is_compact s, from is_compact_of_is_closed_subset (is_compact_closed_ball x r) hs (subset.trans h ball_subset_closed_ball), obtain ⟨y, hys, hy⟩ : ∃ y ∈ s, s ⊆ clo...
lemma
exists_pos_lt_subset_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_const", "continuous_on", "exists_between", "is_closed", "is_compact", "is_compact_of_is_closed_subset" ]
If a nonempty ball in a proper space includes a closed set `s`, then there exists a nonempty ball with the same center and a strictly smaller radius that includes `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_lt_subset_ball (hs : is_closed s) (h : s ⊆ ball x r) : ∃ r' < r, s ⊆ ball x r'
begin cases le_or_lt r 0 with hr hr, { rw [ball_eq_empty.2 hr, subset_empty_iff] at h, unfreezingI { subst s }, exact (exists_lt r).imp (λ r' hr', ⟨hr', empty_subset _⟩) }, { exact (exists_pos_lt_subset_ball hr hs h).imp (λ r' hr', ⟨hr'.fst.2, hr'.snd⟩) } end
lemma
exists_lt_subset_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "exists_pos_lt_subset_ball", "is_closed" ]
If a ball in a proper space includes a closed set `s`, then there exists a ball with the same center and a strictly smaller radius that includes `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact.is_separable {s : set α} (hs : is_compact s) : is_separable s
begin haveI : compact_space s := is_compact_iff_compact_space.mp hs, exact is_separable_of_separable_space_subtype s, end
lemma
is_compact.is_separable
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "compact_space", "is_compact", "is_separable" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
second_countable_of_almost_dense_set (H : ∀ε > (0 : ℝ), ∃ s : set α, s.countable ∧ (∀x, ∃y ∈ s, dist x y ≤ ε)) : second_countable_topology α
begin refine emetric.second_countable_of_almost_dense_set (λ ε ε0, _), rcases ennreal.lt_iff_exists_nnreal_btwn.1 ε0 with ⟨ε', ε'0, ε'ε⟩, choose s hsc y hys hyx using H ε' (by exact_mod_cast ε'0), refine ⟨s, hsc, Union₂_eq_univ_iff.2 (λ x, ⟨y x, hys _, le_trans _ ε'ε.le⟩)⟩, exact_mod_cast hyx x end
lemma
metric.second_countable_of_almost_dense_set
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.second_countable_of_almost_dense_set" ]
A pseudometric space is second countable if, for every `ε > 0`, there is a countable set which is `ε`-dense.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lebesgue_number_lemma_of_metric {s : set α} {ι} {c : ι → set α} (hs : is_compact s) (hc₁ : ∀ i, is_open (c i)) (hc₂ : s ⊆ ⋃ i, c i) : ∃ δ > 0, ∀ x ∈ s, ∃ i, ball x δ ⊆ c i
let ⟨n, en, hn⟩ := lebesgue_number_lemma hs hc₁ hc₂, ⟨δ, δ0, hδ⟩ := mem_uniformity_dist.1 en in ⟨δ, δ0, assume x hx, let ⟨i, hi⟩ := hn x hx in ⟨i, assume y hy, hi (hδ (mem_ball'.mp hy))⟩⟩
lemma
lebesgue_number_lemma_of_metric
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact", "is_open", "lebesgue_number_lemma" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lebesgue_number_lemma_of_metric_sUnion {s : set α} {c : set (set α)} (hs : is_compact s) (hc₁ : ∀ t ∈ c, is_open t) (hc₂ : s ⊆ ⋃₀ c) : ∃ δ > 0, ∀ x ∈ s, ∃ t ∈ c, ball x δ ⊆ t
by rw sUnion_eq_Union at hc₂; simpa using lebesgue_number_lemma_of_metric hs (by simpa) hc₂
lemma
lebesgue_number_lemma_of_metric_sUnion
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact", "is_open", "lebesgue_number_lemma_of_metric" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded (s : set α) : Prop
∃C, ∀x y ∈ s, dist x y ≤ C
def
metric.bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
Boundedness of a subset of a pseudometric space. We formulate the definition to work even in the empty space.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_iff_is_bounded (s : set α) : bounded s ↔ is_bounded s
begin change bounded s ↔ sᶜ ∈ (cobounded α).sets, simp [pseudo_metric_space.cobounded_sets, metric.bounded], end
lemma
metric.bounded_iff_is_bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "metric.bounded" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_empty : bounded (∅ : set α)
⟨0, by simp⟩
lemma
metric.bounded_empty
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
nonempty_of_unbounded (h : ¬ bounded s) : s.nonempty
begin rw nonempty_iff_ne_empty, rintro rfl, exact h bounded_empty end
lemma
metric.nonempty_of_unbounded
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
bounded_iff_mem_bounded : bounded s ↔ ∀ x ∈ s, bounded s
⟨λ h _ _, h, λ H, s.eq_empty_or_nonempty.elim (λ hs, hs.symm ▸ bounded_empty) (λ ⟨x, hx⟩, H x hx)⟩
lemma
metric.bounded_iff_mem_bounded
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
bounded.mono (incl : s ⊆ t) : bounded t → bounded s
Exists.imp $ λ C hC x hx y hy, hC x (incl hx) y (incl hy)
lemma
metric.bounded.mono
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "Exists.imp" ]
Subsets of a bounded set are also bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_closed_ball : bounded (closed_ball x r)
⟨r + r, λ y hy z hz, begin simp only [mem_closed_ball] at *, calc dist y z ≤ dist y x + dist z x : dist_triangle_right _ _ _ ... ≤ r + r : add_le_add hy hz end⟩
lemma
metric.bounded_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_triangle_right" ]
Closed balls are bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_ball : bounded (ball x r)
bounded_closed_ball.mono ball_subset_closed_ball
lemma
metric.bounded_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
Open balls are bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_sphere : bounded (sphere x r)
bounded_closed_ball.mono sphere_subset_closed_ball
lemma
metric.bounded_sphere
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
Spheres are bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_iff_subset_ball (c : α) : bounded s ↔ ∃r, s ⊆ closed_ball c r
begin split; rintro ⟨C, hC⟩, { cases s.eq_empty_or_nonempty with h h, { subst s, exact ⟨0, by simp⟩ }, { rcases h with ⟨x, hx⟩, exact ⟨C + dist x c, λ y hy, calc dist y c ≤ dist y x + dist x c : dist_triangle _ _ _ ... ≤ C + dist x c : add_le_add_right (hC y hy x hx) _⟩ } }, { ex...
lemma
metric.bounded_iff_subset_ball
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" ]
Given a point, a bounded subset is included in some ball around this point
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded.subset_ball (h : bounded s) (c : α) : ∃ r, s ⊆ closed_ball c r
(bounded_iff_subset_ball c).1 h
lemma
metric.bounded.subset_ball
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
bounded.subset_ball_lt (h : bounded s) (a : ℝ) (c : α) : ∃ r, a < r ∧ s ⊆ closed_ball c r
begin rcases h.subset_ball c with ⟨r, hr⟩, refine ⟨max r (a+1), lt_of_lt_of_le (by linarith) (le_max_right _ _), _⟩, exact subset.trans hr (closed_ball_subset_closed_ball (le_max_left _ _)) end
lemma
metric.bounded.subset_ball_lt
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
bounded_closure_of_bounded (h : bounded s) : bounded (closure s)
let ⟨C, h⟩ := h in ⟨C, λ a ha b hb, (is_closed_le' C).closure_subset $ map_mem_closure₂ continuous_dist ha hb h⟩
lemma
metric.bounded_closure_of_bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "continuous_dist", "is_closed_le'", "map_mem_closure₂" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_closure_iff : bounded (closure s) ↔ bounded s
⟨λ h, h.mono subset_closure, λ h, h.closure⟩
lemma
metric.bounded_closure_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "subset_closure" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded.union (hs : bounded s) (ht : bounded t) : bounded (s ∪ t)
begin refine bounded_iff_mem_bounded.2 (λ x _, _), rw bounded_iff_subset_ball x at hs ht ⊢, rcases hs with ⟨Cs, hCs⟩, rcases ht with ⟨Ct, hCt⟩, exact ⟨max Cs Ct, union_subset (subset.trans hCs $ closed_ball_subset_closed_ball $ le_max_left _ _) (subset.trans hCt $ closed_ball_subset_closed_ball $ le_max...
lemma
metric.bounded.union
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
The union of two bounded sets is bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_union : bounded (s ∪ t) ↔ bounded s ∧ bounded t
⟨λ h, ⟨h.mono (by simp), h.mono (by simp)⟩, λ h, h.1.union h.2⟩
lemma
metric.bounded_union
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
The union of two sets is bounded iff each of the sets is bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_bUnion {I : set β} {s : β → set α} (H : I.finite) : bounded (⋃i∈I, s i) ↔ ∀i ∈ I, bounded (s i)
finite.induction_on H (by simp) $ λ x I _ _ IH, by simp [or_imp_distrib, forall_and_distrib, IH]
lemma
metric.bounded_bUnion
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "forall_and_distrib", "or_imp_distrib" ]
A finite union of bounded sets is bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded.prod [pseudo_metric_space β] {s : set α} {t : set β} (hs : bounded s) (ht : bounded t) : bounded (s ×ˢ t)
begin refine bounded_iff_mem_bounded.mpr (λ x hx, _), rcases hs.subset_ball x.1 with ⟨rs, hrs⟩, rcases ht.subset_ball x.2 with ⟨rt, hrt⟩, suffices : s ×ˢ t ⊆ closed_ball x (max rs rt), from bounded_closed_ball.mono this, rw [← @prod.mk.eta _ _ x, ← closed_ball_prod_same], exact prod_mono (hrs.trans $ cl...
lemma
metric.bounded.prod
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closed_ball_prod_same", "pseudo_metric_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.totally_bounded.bounded {s : set α} (h : totally_bounded s) : bounded s
-- We cover the totally bounded set by finitely many balls of radius 1, -- and then argue that a finite union of bounded sets is bounded let ⟨t, fint, subs⟩ := (totally_bounded_iff.mp h) 1 zero_lt_one in bounded.mono subs $ (bounded_bUnion fint).2 $ λ i hi, bounded_ball
lemma
totally_bounded.bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "totally_bounded", "zero_lt_one" ]
A totally bounded set is bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.is_compact.bounded {s : set α} (h : is_compact s) : bounded s
-- A compact set is totally bounded, thus bounded h.totally_bounded.bounded
lemma
is_compact.bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_compact" ]
A compact set is bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_of_finite {s : set α} (h : s.finite) : bounded s
h.is_compact.bounded
lemma
metric.bounded_of_finite
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
A finite set is bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_singleton {x : α} : bounded ({x} : set α)
bounded_of_finite $ finite_singleton _
lemma
metric.bounded_singleton
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
A singleton is bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_range_iff {f : β → α} : bounded (range f) ↔ ∃C, ∀x y, dist (f x) (f y) ≤ C
exists_congr $ λ C, ⟨ λ H x y, H _ ⟨x, rfl⟩ _ ⟨y, rfl⟩, by rintro H _ ⟨x, rfl⟩ _ ⟨y, rfl⟩; exact H x y⟩
lemma
metric.bounded_range_iff
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
Characterization of the boundedness of the range of a function
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_range_of_tendsto_cofinite_uniformity {f : β → α} (hf : tendsto (prod.map f f) (cofinite ×ᶠ cofinite) (𝓤 α)) : bounded (range f)
begin rcases (has_basis_cofinite.prod_self.tendsto_iff uniformity_basis_dist).1 hf 1 zero_lt_one with ⟨s, hsf, hs1⟩, rw [← image_univ, ← union_compl_self s, image_union, bounded_union], use [(hsf.image f).bounded, 1], rintro _ ⟨x, hx, rfl⟩ _ ⟨y, hy, rfl⟩, exact le_of_lt (hs1 (x, y) ⟨hx, hy⟩) end
lemma
metric.bounded_range_of_tendsto_cofinite_uniformity
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "zero_lt_one" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_range_of_cauchy_map_cofinite {f : β → α} (hf : cauchy (map f cofinite)) : bounded (range f)
bounded_range_of_tendsto_cofinite_uniformity $ (cauchy_map_iff.1 hf).2
lemma
metric.bounded_range_of_cauchy_map_cofinite
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.cauchy_seq.bounded_range {f : ℕ → α} (hf : cauchy_seq f) : bounded (range f)
bounded_range_of_cauchy_map_cofinite $ by rwa nat.cofinite_eq_at_top
lemma
cauchy_seq.bounded_range
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq", "nat.cofinite_eq_at_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_range_of_tendsto_cofinite {f : β → α} {a : α} (hf : tendsto f cofinite (𝓝 a)) : bounded (range f)
bounded_range_of_tendsto_cofinite_uniformity $ (hf.prod_map hf).mono_right $ nhds_prod_eq.symm.trans_le (nhds_le_uniformity a)
lemma
metric.bounded_range_of_tendsto_cofinite
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "nhds_le_uniformity" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_of_compact_space [compact_space α] : bounded s
is_compact_univ.bounded.mono (subset_univ _)
lemma
metric.bounded_of_compact_space
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "compact_space" ]
In a compact space, all sets are bounded
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_range_of_tendsto (u : ℕ → α) {x : α} (hu : tendsto u at_top (𝓝 x)) : bounded (range u)
hu.cauchy_seq.bounded_range
lemma
metric.bounded_range_of_tendsto
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
exists_is_open_bounded_image_inter_of_is_compact_of_forall_continuous_within_at [topological_space β] {k s : set β} {f : β → α} (hk : is_compact k) (hf : ∀ x ∈ k, continuous_within_at f s x) : ∃ t, k ⊆ t ∧ is_open t ∧ bounded (f '' (t ∩ s))
begin apply hk.induction_on, { exact ⟨∅, subset.refl _, is_open_empty, by simp only [image_empty, bounded_empty, empty_inter]⟩ }, { rintros s s' hss' ⟨t, s't, t_open, t_bounded⟩, exact ⟨t, hss'.trans s't, t_open, t_bounded⟩ }, { rintros s s' ⟨t, st, t_open, t_bounded⟩ ⟨t', s't', t'_open, t'_bounded⟩, ...
lemma
metric.exists_is_open_bounded_image_inter_of_is_compact_of_forall_continuous_within_at
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_within_at", "is_compact", "is_open", "is_open_empty", "nhds_within_le_nhds", "topological_space", "zero_lt_one" ]
If a function is continuous within a set `s` at every point of a compact set `k`, then it is bounded on some open neighborhood of `k` in `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_is_open_bounded_image_of_is_compact_of_forall_continuous_at [topological_space β] {k : set β} {f : β → α} (hk : is_compact k) (hf : ∀ x ∈ k, continuous_at f x) : ∃ t, k ⊆ t ∧ is_open t ∧ bounded (f '' t)
begin simp_rw ← continuous_within_at_univ at hf, simpa only [inter_univ] using exists_is_open_bounded_image_inter_of_is_compact_of_forall_continuous_within_at hk hf, end
lemma
metric.exists_is_open_bounded_image_of_is_compact_of_forall_continuous_at
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_at", "continuous_within_at_univ", "is_compact", "is_open", "topological_space" ]
If a function is continuous at every point of a compact set `k`, then it is bounded on some open neighborhood of `k`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_is_open_bounded_image_inter_of_is_compact_of_continuous_on [topological_space β] {k s : set β} {f : β → α} (hk : is_compact k) (hks : k ⊆ s) (hf : continuous_on f s) : ∃ t, k ⊆ t ∧ is_open t ∧ bounded (f '' (t ∩ s))
exists_is_open_bounded_image_inter_of_is_compact_of_forall_continuous_within_at hk (λ x hx, hf x (hks hx))
lemma
metric.exists_is_open_bounded_image_inter_of_is_compact_of_continuous_on
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_on", "is_compact", "is_open", "topological_space" ]
If a function is continuous on a set `s` containing a compact set `k`, then it is bounded on some open neighborhood of `k` in `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_is_open_bounded_image_of_is_compact_of_continuous_on [topological_space β] {k s : set β} {f : β → α} (hk : is_compact k) (hs : is_open s) (hks : k ⊆ s) (hf : continuous_on f s) : ∃ t, k ⊆ t ∧ is_open t ∧ bounded (f '' t)
exists_is_open_bounded_image_of_is_compact_of_forall_continuous_at hk (λ x hx, hf.continuous_at (hs.mem_nhds (hks hx)))
lemma
metric.exists_is_open_bounded_image_of_is_compact_of_continuous_on
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "continuous_on", "is_compact", "is_open", "topological_space" ]
If a function is continuous on a neighborhood of a compact set `k`, then it is bounded on some open neighborhood of `k`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact_of_is_closed_bounded [proper_space α] (hc : is_closed s) (hb : bounded s) : is_compact s
begin unfreezingI { rcases eq_empty_or_nonempty s with (rfl|⟨x, hx⟩) }, { exact is_compact_empty }, { rcases hb.subset_ball x with ⟨r, hr⟩, exact is_compact_of_is_closed_subset (is_compact_closed_ball x r) hc hr } end
lemma
metric.is_compact_of_is_closed_bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_closed", "is_compact", "is_compact_empty", "is_compact_of_is_closed_subset", "proper_space" ]
The **Heine–Borel theorem**: In a proper space, a closed bounded set is compact.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded.is_compact_closure [proper_space α] (h : bounded s) : is_compact (closure s)
is_compact_of_is_closed_bounded is_closed_closure h.closure
lemma
metric.bounded.is_compact_closure
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "closure", "is_closed_closure", "is_compact", "proper_space" ]
The **Heine–Borel theorem**: In a proper space, the closure of a bounded set is compact.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_compact_iff_is_closed_bounded [t2_space α] [proper_space α] : is_compact s ↔ is_closed s ∧ bounded s
⟨λ h, ⟨h.is_closed, h.bounded⟩, λ h, is_compact_of_is_closed_bounded h.1 h.2⟩
lemma
metric.is_compact_iff_is_closed_bounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "is_closed", "is_compact", "proper_space", "t2_space" ]
The **Heine–Borel theorem**: In a proper Hausdorff space, a set is compact if and only if it is closed and bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
compact_space_iff_bounded_univ [proper_space α] : compact_space α ↔ bounded (univ : set α)
⟨@bounded_of_compact_space α _ _, λ hb, ⟨is_compact_of_is_closed_bounded is_closed_univ hb⟩⟩
lemma
metric.compact_space_iff_bounded_univ
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "compact_space", "is_closed_univ", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_Icc (a b : α) : bounded (Icc a b)
(totally_bounded_Icc a b).bounded
lemma
metric.bounded_Icc
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "totally_bounded_Icc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_Ico (a b : α) : bounded (Ico a b)
(totally_bounded_Ico a b).bounded
lemma
metric.bounded_Ico
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "totally_bounded_Ico" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_Ioc (a b : α) : bounded (Ioc a b)
(totally_bounded_Ioc a b).bounded
lemma
metric.bounded_Ioc
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "totally_bounded_Ioc" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_Ioo (a b : α) : bounded (Ioo a b)
(totally_bounded_Ioo a b).bounded
lemma
metric.bounded_Ioo
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "totally_bounded_Ioo" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_of_bdd_above_of_bdd_below {s : set α} (h₁ : bdd_above s) (h₂ : bdd_below s) : bounded s
let ⟨u, hu⟩ := h₁, ⟨l, hl⟩ := h₂ in bounded.mono (λ x hx, mem_Icc.mpr ⟨hl hx, hu hx⟩) (bounded_Icc l u)
lemma
metric.bounded_of_bdd_above_of_bdd_below
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "bdd_above", "bdd_below" ]
In a pseudo metric space with a conditionally complete linear order such that the order and the metric structure give the same topology, any order-bounded set is metric-bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam (s : set α) : ℝ
ennreal.to_real (emetric.diam s)
def
metric.diam
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam", "ennreal.to_real" ]
The diameter of a set in a metric space. To get controllable behavior even when the diameter should be infinite, we express it in terms of the emetric.diameter
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_nonneg : 0 ≤ diam s
ennreal.to_real_nonneg
lemma
metric.diam_nonneg
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "ennreal.to_real_nonneg" ]
The diameter of a set is always nonnegative
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_subsingleton (hs : s.subsingleton) : diam s = 0
by simp only [diam, emetric.diam_subsingleton hs, ennreal.zero_to_real]
lemma
metric.diam_subsingleton
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam_subsingleton", "ennreal.zero_to_real" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_empty : diam (∅ : set α) = 0
diam_subsingleton subsingleton_empty
lemma
metric.diam_empty
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
The empty set has zero diameter
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_singleton : diam ({x} : set α) = 0
diam_subsingleton subsingleton_singleton
lemma
metric.diam_singleton
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
A singleton has zero diameter
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_one [has_one α] : diam (1 : set α) = 0
diam_singleton
lemma
metric.diam_one
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
diam_pair : diam ({x, y} : set α) = dist x y
by simp only [diam, emetric.diam_pair, dist_edist]
lemma
metric.diam_pair
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_edist", "emetric.diam_pair" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_triple : metric.diam ({x, y, z} : set α) = max (max (dist x y) (dist x z)) (dist y z)
begin simp only [metric.diam, emetric.diam_triple, dist_edist], rw [ennreal.to_real_max, ennreal.to_real_max]; apply_rules [ne_of_lt, edist_lt_top, max_lt] end
lemma
metric.diam_triple
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_edist", "edist_lt_top", "emetric.diam_triple", "ennreal.to_real_max", "metric.diam" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ediam_le_of_forall_dist_le {C : ℝ} (h : ∀ (x ∈ s) (y ∈ s), dist x y ≤ C) : emetric.diam s ≤ ennreal.of_real C
emetric.diam_le $ λ x hx y hy, (edist_dist x y).symm ▸ ennreal.of_real_le_of_real (h x hx y hy)
lemma
metric.ediam_le_of_forall_dist_le
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "edist_dist", "emetric.diam", "emetric.diam_le", "ennreal.of_real", "ennreal.of_real_le_of_real" ]
If the distance between any two points in a set is bounded by some constant `C`, then `ennreal.of_real C` bounds the emetric diameter of this set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_le_of_forall_dist_le {C : ℝ} (h₀ : 0 ≤ C) (h : ∀ (x ∈ s) (y ∈ s), dist x y ≤ C) : diam s ≤ C
ennreal.to_real_le_of_le_of_real h₀ (ediam_le_of_forall_dist_le h)
lemma
metric.diam_le_of_forall_dist_le
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "ennreal.to_real_le_of_le_of_real" ]
If the distance between any two points in a set is bounded by some non-negative constant, this constant bounds the diameter.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_le_of_forall_dist_le_of_nonempty (hs : s.nonempty) {C : ℝ} (h : ∀ (x ∈ s) (y ∈ s), dist x y ≤ C) : diam s ≤ C
have h₀ : 0 ≤ C, from let ⟨x, hx⟩ := hs in le_trans dist_nonneg (h x hx x hx), diam_le_of_forall_dist_le h₀ h
lemma
metric.diam_le_of_forall_dist_le_of_nonempty
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nonneg" ]
If the distance between any two points in a nonempty set is bounded by some constant, this constant bounds the diameter.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_le_diam_of_mem' (h : emetric.diam s ≠ ⊤) (hx : x ∈ s) (hy : y ∈ s) : dist x y ≤ diam s
begin rw [diam, dist_edist], rw ennreal.to_real_le_to_real (edist_ne_top _ _) h, exact emetric.edist_le_diam_of_mem hx hy end
lemma
metric.dist_le_diam_of_mem'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_edist", "edist_ne_top", "emetric.diam", "emetric.edist_le_diam_of_mem", "ennreal.to_real_le_to_real" ]
The distance between two points in a set is controlled by the diameter of the set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded_iff_ediam_ne_top : bounded s ↔ emetric.diam s ≠ ⊤
iff.intro (λ ⟨C, hC⟩, ne_top_of_le_ne_top ennreal.of_real_ne_top $ ediam_le_of_forall_dist_le hC) (λ h, ⟨diam s, λ x hx y hy, dist_le_diam_of_mem' h hx hy⟩)
lemma
metric.bounded_iff_ediam_ne_top
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam", "ennreal.of_real_ne_top", "ne_top_of_le_ne_top" ]
Characterize the boundedness of a set in terms of the finiteness of its emetric.diameter.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
bounded.ediam_ne_top (h : bounded s) : emetric.diam s ≠ ⊤
bounded_iff_ediam_ne_top.1 h
lemma
metric.bounded.ediam_ne_top
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ediam_univ_eq_top_iff_noncompact [proper_space α] : emetric.diam (univ : set α) = ∞ ↔ noncompact_space α
by rw [← not_compact_space_iff, compact_space_iff_bounded_univ, bounded_iff_ediam_ne_top, not_not]
lemma
metric.ediam_univ_eq_top_iff_noncompact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam", "noncompact_space", "not_compact_space_iff", "not_not", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ediam_univ_of_noncompact [proper_space α] [noncompact_space α] : emetric.diam (univ : set α) = ∞
ediam_univ_eq_top_iff_noncompact.mpr ‹_›
lemma
metric.ediam_univ_of_noncompact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam", "noncompact_space", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_univ_of_noncompact [proper_space α] [noncompact_space α] : diam (univ : set α) = 0
by simp [diam]
lemma
metric.diam_univ_of_noncompact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "noncompact_space", "proper_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_le_diam_of_mem (h : bounded s) (hx : x ∈ s) (hy : y ∈ s) : dist x y ≤ diam s
dist_le_diam_of_mem' h.ediam_ne_top hx hy
lemma
metric.dist_le_diam_of_mem
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 between two points in a set is controlled by the diameter of the set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ediam_of_unbounded (h : ¬(bounded s)) : emetric.diam s = ∞
by rwa [bounded_iff_ediam_ne_top, not_not] at h
lemma
metric.ediam_of_unbounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam", "not_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_eq_zero_of_unbounded (h : ¬(bounded s)) : diam s = 0
by rw [diam, ediam_of_unbounded h, ennreal.top_to_real]
lemma
metric.diam_eq_zero_of_unbounded
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "ennreal.top_to_real" ]
An unbounded set has zero diameter. If you would prefer to get the value ∞, use `emetric.diam`. This lemma makes it possible to avoid side conditions in some situations
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_mono {s t : set α} (h : s ⊆ t) (ht : bounded t) : diam s ≤ diam t
begin unfold diam, rw ennreal.to_real_le_to_real (bounded.mono h ht).ediam_ne_top ht.ediam_ne_top, exact emetric.diam_mono h end
lemma
metric.diam_mono
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "emetric.diam_mono", "ennreal.to_real_le_to_real" ]
If `s ⊆ t`, then the diameter of `s` is bounded by that of `t`, provided `t` is bounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_union {t : set α} (xs : x ∈ s) (yt : y ∈ t) : diam (s ∪ t) ≤ diam s + dist x y + diam t
begin by_cases H : bounded (s ∪ t), { have hs : bounded s, from H.mono (subset_union_left _ _), have ht : bounded t, from H.mono (subset_union_right _ _), rw [bounded_iff_ediam_ne_top] at H hs ht, rw [dist_edist, diam, diam, diam, ← ennreal.to_real_add, ← ennreal.to_real_add, ennreal.to_real_le_to...
lemma
metric.diam_union
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_edist", "dist_nonneg", "edist_ne_top", "emetric.diam_union", "ennreal.to_real_add", "ennreal.to_real_le_to_real" ]
The diameter of a union is controlled by the sum of the diameters, and the distance between any two points in each of the sets. This lemma is true without any side condition, since it is obviously true if `s ∪ t` is unbounded.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_union' {t : set α} (h : (s ∩ t).nonempty) : diam (s ∪ t) ≤ diam s + diam t
begin rcases h with ⟨x, ⟨xs, xt⟩⟩, simpa using diam_union xs xt end
lemma
metric.diam_union'
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
If two sets intersect, the diameter of the union is bounded by the sum of the diameters.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_le_of_subset_closed_ball {r : ℝ} (hr : 0 ≤ r) (h : s ⊆ closed_ball x r) : diam s ≤ 2 * r
diam_le_of_forall_dist_le (mul_nonneg zero_le_two hr) $ λa ha b hb, calc dist a b ≤ dist a x + dist b x : dist_triangle_right _ _ _ ... ≤ r + r : add_le_add (h ha) (h hb) ... = 2 * r : by simp [mul_two, mul_comm]
lemma
metric.diam_le_of_subset_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_triangle_right", "mul_comm", "mul_two", "zero_le_two" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_closed_ball {r : ℝ} (h : 0 ≤ r) : diam (closed_ball x r) ≤ 2 * r
diam_le_of_subset_closed_ball h subset.rfl
lemma
metric.diam_closed_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
The diameter of a closed ball of radius `r` is at most `2 r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diam_ball {r : ℝ} (h : 0 ≤ r) : diam (ball x r) ≤ 2 * r
diam_le_of_subset_closed_ball h ball_subset_closed_ball
lemma
metric.diam_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[]
The diameter of a ball of radius `r` is at most `2 r`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.is_complete.nonempty_Inter_of_nonempty_bInter {s : ℕ → set α} (h0 : is_complete (s 0)) (hs : ∀ n, is_closed (s n)) (h's : ∀ n, bounded (s n)) (h : ∀ N, (⋂ n ≤ N, s n).nonempty) (h' : tendsto (λ n, diam (s n)) at_top (𝓝 0)) : (⋂ n, s n).nonempty
begin let u := λ N, (h N).some, have I : ∀ n N, n ≤ N → u N ∈ s n, { assume n N hn, apply mem_of_subset_of_mem _ ((h N).some_spec), assume x hx, simp only [mem_Inter] at hx, exact hx n hn }, have : ∀ n, u n ∈ s 0 := λ n, I 0 n (zero_le _), have : cauchy_seq u, { apply cauchy_seq_of_le_tendst...
lemma
is_complete.nonempty_Inter_of_nonempty_bInter
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "cauchy_seq", "cauchy_seq_of_le_tendsto_0", "cauchy_seq_tendsto_of_is_complete", "is_closed", "is_complete" ]
If a family of complete sets with diameter tending to `0` is such that each finite intersection is nonempty, then the total intersection is also nonempty.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nonempty_Inter_of_nonempty_bInter [complete_space α] {s : ℕ → set α} (hs : ∀ n, is_closed (s n)) (h's : ∀ n, bounded (s n)) (h : ∀ N, (⋂ n ≤ N, s n).nonempty) (h' : tendsto (λ n, diam (s n)) at_top (𝓝 0)) : (⋂ n, s n).nonempty
(hs 0).is_complete.nonempty_Inter_of_nonempty_bInter hs h's h h'
lemma
metric.nonempty_Inter_of_nonempty_bInter
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "complete_space", "is_closed", "is_complete.nonempty_Inter_of_nonempty_bInter" ]
In a complete space, if a family of closed sets with diameter tending to `0` is such that each finite intersection is nonempty, then the total intersection is also nonempty.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_local_min_mem_ball [proper_space α] [topological_space β] [conditionally_complete_linear_order β] [order_topology β] {f : α → β} {a z : α} {r : ℝ} (hf : continuous_on f (closed_ball a r)) (hz : z ∈ closed_ball a r) (hf1 : ∀ z' ∈ sphere a r, f z < f z') : ∃ z ∈ ball a r, is_local_min f z
begin simp_rw [← closed_ball_diff_ball] at hf1, exact (is_compact_closed_ball a r).exists_local_min_mem_open ball_subset_closed_ball hf hz hf1 is_open_ball, end
lemma
metric.exists_local_min_mem_ball
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "conditionally_complete_linear_order", "continuous_on", "is_local_min", "order_topology", "proper_space", "topological_space" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
positivity_diam : expr → tactic strictness
| `(metric.diam %%s) := nonnegative <$> mk_app ``metric.diam_nonneg [s] | e := pp e >>= fail ∘ format.bracket "The expression " " is not of the form `metric.diam s`"
def
tactic.positivity_diam
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "metric.diam_nonneg" ]
Extension for the `positivity` tactic: the diameter of a set is always nonnegative.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_dist_right_at_top_le_cocompact (x : α) : comap (λ y, dist y x) at_top ≤ cocompact α
begin refine filter.has_basis_cocompact.ge_iff.2 (λ s hs, mem_comap.2 _), rcases hs.bounded.subset_ball x with ⟨r, hr⟩, exact ⟨Ioi r, Ioi_mem_at_top r, λ y hy hys, (mem_closed_ball.1 $ hr hys).not_lt hy⟩ end
lemma
comap_dist_right_at_top_le_cocompact
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
comap_dist_left_at_top_le_cocompact (x : α) : comap (dist x) at_top ≤ cocompact α
by simpa only [dist_comm _ x] using comap_dist_right_at_top_le_cocompact x
lemma
comap_dist_left_at_top_le_cocompact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "comap_dist_right_at_top_le_cocompact", "dist_comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_dist_right_at_top_eq_cocompact [proper_space α] (x : α) : comap (λ y, dist y x) at_top = cocompact α
(comap_dist_right_at_top_le_cocompact x).antisymm $ (tendsto_dist_right_cocompact_at_top x).le_comap
lemma
comap_dist_right_at_top_eq_cocompact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "comap_dist_right_at_top_le_cocompact", "proper_space", "tendsto_dist_right_cocompact_at_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comap_dist_left_at_top_eq_cocompact [proper_space α] (x : α) : comap (dist x) at_top = cocompact α
(comap_dist_left_at_top_le_cocompact x).antisymm $ (tendsto_dist_left_cocompact_at_top x).le_comap
lemma
comap_dist_left_at_top_eq_cocompact
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "comap_dist_left_at_top_le_cocompact", "proper_space", "tendsto_dist_left_cocompact_at_top" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_cocompact_of_tendsto_dist_comp_at_top {f : β → α} {l : filter β} (x : α) (h : tendsto (λ y, dist (f y) x) l at_top) : tendsto f l (cocompact α)
by { refine tendsto.mono_right _ (comap_dist_right_at_top_le_cocompact x), rwa tendsto_comap_iff }
lemma
tendsto_cocompact_of_tendsto_dist_comp_at_top
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "comap_dist_right_at_top_le_cocompact", "filter" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
metric_space (α : Type u) extends pseudo_metric_space α : Type u
(eq_of_dist_eq_zero : ∀ {x y : α}, dist x y = 0 → x = y)
class
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" ]
[ "eq_of_dist_eq_zero", "pseudo_metric_space" ]
We now define `metric_space`, extending `pseudo_metric_space`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
metric_space.ext {α : Type*} {m m' : metric_space α} (h : m.to_has_dist = m'.to_has_dist) : m = m'
begin have h' : m.to_pseudo_metric_space = m'.to_pseudo_metric_space := pseudo_metric_space.ext h, unfreezingI { rcases m, rcases m' }, dsimp at h', unfreezingI { subst h' }, end
lemma
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" ]
[ "metric_space", "pseudo_metric_space.ext" ]
Two metric space structures with the same distance coincide.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
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) (eq_of_d...
{ eq_of_dist_eq_zero := eq_of_dist_eq_zero, ..pseudo_metric_space.of_dist_topology dist dist_self dist_comm dist_triangle H }
def
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" ]
[ "dist_comm", "dist_self", "dist_triangle", "eq_of_dist_eq_zero", "is_open", "metric_space", "pseudo_metric_space.of_dist_topology", "topological_space" ]
Construct a 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
eq_of_dist_eq_zero {x y : γ} : dist x y = 0 → x = y
metric_space.eq_of_dist_eq_zero
theorem
eq_of_dist_eq_zero
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_eq_zero {x y : γ} : dist x y = 0 ↔ x = y
iff.intro eq_of_dist_eq_zero (assume : x = y, this ▸ dist_self _)
theorem
dist_eq_zero
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_self", "eq_of_dist_eq_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_eq_dist {x y : γ} : 0 = dist x y ↔ x = y
by rw [eq_comm, dist_eq_zero]
theorem
zero_eq_dist
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_eq_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_ne_zero {x y : γ} : dist x y ≠ 0 ↔ x ≠ y
by simpa only [not_iff_not] using dist_eq_zero
theorem
dist_ne_zero
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_eq_zero", "not_iff_not" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_le_zero {x y : γ} : dist x y ≤ 0 ↔ x = y
by simpa [le_antisymm_iff, dist_nonneg] using @dist_eq_zero _ _ x y
theorem
dist_le_zero
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_eq_zero", "dist_nonneg" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dist_pos {x y : γ} : 0 < dist x y ↔ x ≠ y
by simpa only [not_le] using not_congr dist_le_zero
theorem
dist_pos
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_le_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_of_forall_dist_le {x y : γ} (h : ∀ ε > 0, dist x y ≤ ε) : x = y
eq_of_dist_eq_zero (eq_of_le_of_forall_le_of_dense dist_nonneg h)
theorem
eq_of_forall_dist_le
topology.metric_space
src/topology/metric_space/basic.lean
[ "tactic.positivity", "topology.algebra.order.compact", "topology.metric_space.emetric_space", "topology.bornology.constructions" ]
[ "dist_nonneg", "eq_of_dist_eq_zero", "eq_of_le_of_forall_le_of_dense" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83