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is_open.prod {s : set α} {t : set β} (hs : is_open s) (ht : is_open t) : is_open (s ×ˢ t)
(hs.preimage continuous_fst).inter (ht.preimage continuous_snd)
lemma
is_open.prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_fst", "continuous_snd", "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_prod_eq {a : α} {b : β} : 𝓝 (a, b) = 𝓝 a ×ᶠ 𝓝 b
by rw [filter.prod, prod.topological_space, nhds_inf, nhds_induced, nhds_induced]
lemma
nhds_prod_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter.prod", "nhds_induced", "nhds_inf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_uncurry_of_discrete_topology [discrete_topology α] {f : α → β → γ} (hf : ∀ a, continuous (f a)) : continuous (uncurry f)
begin apply continuous_iff_continuous_at.2, rintros ⟨a, x⟩, change map _ _ ≤ _, rw [nhds_prod_eq, nhds_discrete, filter.map_pure_prod], exact (hf a).continuous_at end
lemma
continuous_uncurry_of_discrete_topology
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_at", "discrete_topology", "filter.map_pure_prod", "nhds_discrete", "nhds_prod_eq" ]
If a function `f x y` is such that `y ↦ f x y` is continuous for all `x`, and `x` lives in a discrete space, then `f` is continuous.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nhds_prod_iff {a : α} {b : β} {s : set (α × β)} : s ∈ 𝓝 (a, b) ↔ ∃ (u ∈ 𝓝 a) (v ∈ 𝓝 b), u ×ˢ v ⊆ s
by rw [nhds_prod_eq, mem_prod_iff]
lemma
mem_nhds_prod_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mem_nhds_prod_iff' {a : α} {b : β} {s : set (α × β)} : s ∈ 𝓝 (a, b) ↔ ∃ (u : set α) (v : set β), is_open u ∧ a ∈ u ∧ is_open v ∧ b ∈ v ∧ u ×ˢ v ⊆ s
begin rw mem_nhds_prod_iff, split, { rintros ⟨u, Hu, v, Hv, h⟩, rcases mem_nhds_iff.1 Hu with ⟨u', u'u, u'_open, Hu'⟩, rcases mem_nhds_iff.1 Hv with ⟨v', v'v, v'_open, Hv'⟩, exact ⟨u', v', u'_open, Hu', v'_open, Hv', (set.prod_mono u'u v'v).trans h⟩ }, { rintros ⟨u, v, u_open, au, v_open, bv, huv⟩, ...
lemma
mem_nhds_prod_iff'
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "mem_nhds_prod_iff", "set.prod_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
_root_.prod.tendsto_iff {α} (seq : α → β × γ) {f : filter α} (x : β × γ) : tendsto seq f (𝓝 x) ↔ tendsto (λ n, (seq n).fst) f (𝓝 x.fst) ∧ tendsto (λ n, (seq n).snd) f (𝓝 x.snd)
by { cases x, rw [nhds_prod_eq, filter.tendsto_prod_iff'], }
lemma
prod.tendsto_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter", "filter.tendsto_prod_iff'", "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.prod_nhds {ιa ιb : Type*} {pa : ιa → Prop} {pb : ιb → Prop} {sa : ιa → set α} {sb : ιb → set β} {a : α} {b : β} (ha : (𝓝 a).has_basis pa sa) (hb : (𝓝 b).has_basis pb sb) : (𝓝 (a, b)).has_basis (λ i : ιa × ιb, pa i.1 ∧ pb i.2) (λ i, sa i.1 ×ˢ sb i.2)
by { rw nhds_prod_eq, exact ha.prod hb }
lemma
filter.has_basis.prod_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.has_basis.prod_nhds' {ιa ιb : Type*} {pa : ιa → Prop} {pb : ιb → Prop} {sa : ιa → set α} {sb : ιb → set β} {ab : α × β} (ha : (𝓝 ab.1).has_basis pa sa) (hb : (𝓝 ab.2).has_basis pb sb) : (𝓝 ab).has_basis (λ i : ιa × ιb, pa i.1 ∧ pb i.2) (λ i, sa i.1 ×ˢ sb i.2)
by { cases ab, exact ha.prod_nhds hb }
lemma
filter.has_basis.prod_nhds'
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_mem_nhds_iff {s : set α} {t : set β} {a : α} {b : β} : s ×ˢ t ∈ 𝓝 (a, b) ↔ s ∈ 𝓝 a ∧ t ∈ 𝓝 b
by rw [nhds_prod_eq, prod_mem_prod_iff]
lemma
prod_mem_nhds_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_mem_nhds {s : set α} {t : set β} {a : α} {b : β} (ha : s ∈ 𝓝 a) (hb : t ∈ 𝓝 b) : s ×ˢ t ∈ 𝓝 (a, b)
prod_mem_nhds_iff.2 ⟨ha, hb⟩
lemma
prod_mem_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.eventually.prod_nhds {p : α → Prop} {q : β → Prop} {a : α} {b : β} (ha : ∀ᶠ x in 𝓝 a, p x) (hb : ∀ᶠ y in 𝓝 b, q y) : ∀ᶠ z : α × β in 𝓝 (a, b), p z.1 ∧ q z.2
prod_mem_nhds ha hb
lemma
filter.eventually.prod_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "prod_mem_nhds" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_swap (a : α) (b : β) : 𝓝 (a, b) = (𝓝 (b, a)).map prod.swap
by rw [nhds_prod_eq, filter.prod_comm, nhds_prod_eq]; refl
lemma
nhds_swap
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter.prod_comm", "nhds_prod_eq", "prod.swap" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.tendsto.prod_mk_nhds {γ} {a : α} {b : β} {f : filter γ} {ma : γ → α} {mb : γ → β} (ha : tendsto ma f (𝓝 a)) (hb : tendsto mb f (𝓝 b)) : tendsto (λc, (ma c, mb c)) f (𝓝 (a, b))
by rw [nhds_prod_eq]; exact filter.tendsto.prod_mk ha hb
lemma
filter.tendsto.prod_mk_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter", "filter.tendsto.prod_mk", "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
filter.eventually.curry_nhds {p : α × β → Prop} {x : α} {y : β} (h : ∀ᶠ x in 𝓝 (x, y), p x) : ∀ᶠ x' in 𝓝 x, ∀ᶠ y' in 𝓝 y, p (x', y')
by { rw [nhds_prod_eq] at h, exact h.curry }
lemma
filter.eventually.curry_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at.prod {f : α → β} {g : α → γ} {x : α} (hf : continuous_at f x) (hg : continuous_at g x) : continuous_at (λx, (f x, g x)) x
hf.prod_mk_nhds hg
lemma
continuous_at.prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at.prod_map {f : α → γ} {g : β → δ} {p : α × β} (hf : continuous_at f p.fst) (hg : continuous_at g p.snd) : continuous_at (λ p : α × β, (f p.1, g p.2)) p
hf.fst''.prod hg.snd''
lemma
continuous_at.prod_map
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at.prod_map' {f : α → γ} {g : β → δ} {x : α} {y : β} (hf : continuous_at f x) (hg : continuous_at g y) : continuous_at (λ p : α × β, (f p.1, g p.2)) (x, y)
hf.fst'.prod hg.snd'
lemma
continuous_at.prod_map'
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_generate_from_generate_from_eq {α β : Type*} {s : set (set α)} {t : set (set β)} (hs : ⋃₀ s = univ) (ht : ⋃₀ t = univ) : @prod.topological_space α β (generate_from s) (generate_from t) = generate_from {g | ∃ u ∈ s, ∃ v ∈ t, g = u ×ˢ v}
let G := generate_from {g | ∃ u ∈ s, ∃ v ∈ t, g = u ×ˢ v} in le_antisymm (le_generate_from $ λ g ⟨u, hu, v, hv, g_eq⟩, g_eq.symm ▸ @is_open.prod _ _ (generate_from s) (generate_from t) _ _ (generate_open.basic _ hu) (generate_open.basic _ hv)) (le_inf (coinduced_le_iff_le_induced.mp $ le_generate_from...
lemma
prod_generate_from_generate_from_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open.prod", "is_open_Union", "le_generate_from", "le_inf" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_eq_generate_from : prod.topological_space = generate_from {g | ∃(s:set α) (t:set β), is_open s ∧ is_open t ∧ g = s ×ˢ t}
le_antisymm (le_generate_from $ λ g ⟨s, t, hs, ht, g_eq⟩, g_eq.symm ▸ hs.prod ht) (le_inf (ball_image_of_ball $ λt ht, generate_open.basic _ ⟨t, univ, by simpa [set.prod_eq] using ht⟩) (ball_image_of_ball $ λt ht, generate_open.basic _ ⟨univ, t, by simpa [set.prod_eq] using ht⟩))
lemma
prod_eq_generate_from
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "le_generate_from", "le_inf", "set.prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_prod_iff {s : set (α × β)} : is_open s ↔ (∀a b, (a, b) ∈ s → ∃ (u : set α) (v : set β), is_open u ∧ is_open v ∧ a ∈ u ∧ b ∈ v ∧ u ×ˢ v ⊆ s)
begin rw [is_open_iff_nhds], simp_rw [le_principal_iff, prod.forall, ((nhds_basis_opens _).prod_nhds (nhds_basis_opens _)).mem_iff, prod.exists, exists_prop], simp only [and_assoc, and.left_comm] end
lemma
is_open_prod_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "exists_prop", "is_open", "is_open_iff_nhds", "nhds_basis_opens" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod_induced_induced {α γ : Type*} (f : α → β) (g : γ → δ) : @prod.topological_space α γ (induced f ‹_›) (induced g ‹_›) = induced (λ p, (f p.1, g p.2)) prod.topological_space
by simp_rw [prod.topological_space, induced_inf, induced_compose]
lemma
prod_induced_induced
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "induced_compose", "induced_inf" ]
A product of induced topologies is induced by the product map
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_uncurry_of_discrete_topology_left [discrete_topology α] {f : α → β → γ} (h : ∀ a, continuous (f a)) : continuous (uncurry f)
continuous_iff_continuous_at.2 $ λ ⟨a, b⟩, by simp only [continuous_at, nhds_prod_eq, nhds_discrete α, pure_prod, tendsto_map'_iff, (∘), uncurry, (h a).tendsto]
lemma
continuous_uncurry_of_discrete_topology_left
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_at", "discrete_topology", "nhds_discrete", "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_nhds_square {s : set (α × α)} {x : α} (hx : s ∈ 𝓝 (x, x)) : ∃ U : set α, is_open U ∧ x ∈ U ∧ U ×ˢ U ⊆ s
by simpa [nhds_prod_eq, (nhds_basis_opens x).prod_self.mem_iff, and.assoc, and.left_comm] using hx
lemma
exists_nhds_square
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "nhds_basis_opens", "nhds_prod_eq" ]
Given a neighborhood `s` of `(x, x)`, then `(x, x)` has a square open neighborhood that is a subset of `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_fst_nhds_within (x : α × β) : map prod.fst (𝓝[prod.snd ⁻¹' {x.2}] x) = 𝓝 x.1
begin refine le_antisymm (continuous_at_fst.mono_left inf_le_left) (λ s hs, _), rcases x with ⟨x, y⟩, rw [mem_map, nhds_within, mem_inf_principal, mem_nhds_prod_iff] at hs, rcases hs with ⟨u, hu, v, hv, H⟩, simp only [prod_subset_iff, mem_singleton_iff, mem_set_of_eq, mem_preimage] at H, exact mem_of_supers...
lemma
map_fst_nhds_within
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "inf_le_left", "mem_map", "mem_nhds_prod_iff", "mem_of_mem_nhds", "nhds_within" ]
`prod.fst` maps neighborhood of `x : α × β` within the section `prod.snd ⁻¹' {x.2}` to `𝓝 x.1`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_fst_nhds (x : α × β) : map prod.fst (𝓝 x) = 𝓝 x.1
le_antisymm continuous_at_fst $ (map_fst_nhds_within x).symm.trans_le (map_mono inf_le_left)
lemma
map_fst_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at_fst", "inf_le_left", "map_fst_nhds_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map_fst : is_open_map (@prod.fst α β)
is_open_map_iff_nhds_le.2 $ λ x, (map_fst_nhds x).ge
lemma
is_open_map_fst
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open_map", "map_fst_nhds" ]
The first projection in a product of topological spaces sends open sets to open sets.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_snd_nhds_within (x : α × β) : map prod.snd (𝓝[prod.fst ⁻¹' {x.1}] x) = 𝓝 x.2
begin refine le_antisymm (continuous_at_snd.mono_left inf_le_left) (λ s hs, _), rcases x with ⟨x, y⟩, rw [mem_map, nhds_within, mem_inf_principal, mem_nhds_prod_iff] at hs, rcases hs with ⟨u, hu, v, hv, H⟩, simp only [prod_subset_iff, mem_singleton_iff, mem_set_of_eq, mem_preimage] at H, exact mem_of_supers...
lemma
map_snd_nhds_within
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "inf_le_left", "mem_map", "mem_nhds_prod_iff", "mem_of_mem_nhds", "nhds_within" ]
`prod.snd` maps neighborhood of `x : α × β` within the section `prod.fst ⁻¹' {x.1}` to `𝓝 x.2`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_snd_nhds (x : α × β) : map prod.snd (𝓝 x) = 𝓝 x.2
le_antisymm continuous_at_snd $ (map_snd_nhds_within x).symm.trans_le (map_mono inf_le_left)
lemma
map_snd_nhds
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at_snd", "inf_le_left", "map_snd_nhds_within" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map_snd : is_open_map (@prod.snd α β)
is_open_map_iff_nhds_le.2 $ λ x, (map_snd_nhds x).ge
lemma
is_open_map_snd
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open_map", "map_snd_nhds" ]
The second projection in a product of topological spaces sends open sets to open sets.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_prod_iff' {s : set α} {t : set β} : is_open (s ×ˢ t) ↔ (is_open s ∧ is_open t) ∨ (s = ∅) ∨ (t = ∅)
begin cases (s ×ˢ t).eq_empty_or_nonempty with h h, { simp [h, prod_eq_empty_iff.1 h] }, { have st : s.nonempty ∧ t.nonempty, from prod_nonempty_iff.1 h, split, { assume H : is_open (s ×ˢ t), refine or.inl ⟨_, _⟩, show is_open s, { rw ← fst_image_prod s st.2, exact is_open_map_fs...
lemma
is_open_prod_iff'
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "is_open_map_fst", "is_open_map_snd" ]
A product set is open in a product space if and only if each factor is open, or one of them is empty
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_prod_eq {s : set α} {t : set β} : closure (s ×ˢ t) = closure s ×ˢ closure t
set.ext $ assume ⟨a, b⟩, have (𝓝 a ×ᶠ 𝓝 b) ⊓ 𝓟 (s ×ˢ t) = (𝓝 a ⊓ 𝓟 s) ×ᶠ (𝓝 b ⊓ 𝓟 t), by rw [←prod_inf_prod, prod_principal_principal], by simp [closure_eq_cluster_pts, cluster_pt, nhds_prod_eq, this]; exact prod_ne_bot
lemma
closure_prod_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure", "closure_eq_cluster_pts", "cluster_pt", "nhds_prod_eq", "set.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
interior_prod_eq (s : set α) (t : set β) : interior (s ×ˢ t) = interior s ×ˢ interior t
set.ext $ λ ⟨a, b⟩, by simp only [mem_interior_iff_mem_nhds, mem_prod, prod_mem_nhds_iff]
lemma
interior_prod_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "interior", "mem_interior_iff_mem_nhds", "prod_mem_nhds_iff", "set.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frontier_prod_eq (s : set α) (t : set β) : frontier (s ×ˢ t) = closure s ×ˢ frontier t ∪ frontier s ×ˢ closure t
by simp only [frontier, closure_prod_eq, interior_prod_eq, prod_diff_prod]
lemma
frontier_prod_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure", "closure_prod_eq", "frontier", "interior_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frontier_prod_univ_eq (s : set α) : frontier (s ×ˢ (univ : set β)) = frontier s ×ˢ univ
by simp [frontier_prod_eq]
lemma
frontier_prod_univ_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "frontier", "frontier_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
frontier_univ_prod_eq (s : set β) : frontier ((univ : set α) ×ˢ s) = univ ×ˢ frontier s
by simp [frontier_prod_eq]
lemma
frontier_univ_prod_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "frontier", "frontier_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mem_closure₂ {f : α → β → γ} {a : α} {b : β} {s : set α} {t : set β} {u : set γ} (hf : continuous (uncurry f)) (ha : a ∈ closure s) (hb : b ∈ closure t) (h : ∀ (a ∈ s) (b ∈ t), f a b ∈ u) : f a b ∈ closure u
have H₁ : (a, b) ∈ closure (s ×ˢ t), by simpa only [closure_prod_eq] using mk_mem_prod ha hb, have H₂ : maps_to (uncurry f) (s ×ˢ t) u, from forall_prod_set.2 h, H₂.closure hf H₁
lemma
map_mem_closure₂
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure", "closure_prod_eq", "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed.prod {s₁ : set α} {s₂ : set β} (h₁ : is_closed s₁) (h₂ : is_closed s₂) : is_closed (s₁ ×ˢ s₂)
closure_eq_iff_is_closed.mp $ by simp only [h₁.closure_eq, h₂.closure_eq, closure_prod_eq]
lemma
is_closed.prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure_prod_eq", "is_closed" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense.prod {s : set α} {t : set β} (hs : dense s) (ht : dense t) : dense (s ×ˢ t)
λ x, by { rw closure_prod_eq, exact ⟨hs x.1, ht x.2⟩ }
lemma
dense.prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure_prod_eq", "dense" ]
The product of two dense sets is a dense set.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
dense_range.prod_map {ι : Type*} {κ : Type*} {f : ι → β} {g : κ → γ} (hf : dense_range f) (hg : dense_range g) : dense_range (prod.map f g)
by simpa only [dense_range, prod_range_range_eq] using hf.prod hg
lemma
dense_range.prod_map
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "dense_range" ]
If `f` and `g` are maps with dense range, then `prod.map f g` has dense range.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing.prod_mk {f : α → β} {g : γ → δ} (hf : inducing f) (hg : inducing g) : inducing (λx:α×γ, (f x.1, g x.2))
⟨by rw [prod.topological_space, prod.topological_space, hf.induced, hg.induced, induced_compose, induced_compose, induced_inf, induced_compose, induced_compose]⟩
lemma
inducing.prod_mk
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "induced_compose", "induced_inf", "inducing" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing_const_prod {a : α} {f : β → γ} : inducing (λ x, (a, f x)) ↔ inducing f
by simp_rw [inducing_iff, prod.topological_space, induced_inf, induced_compose, function.comp, induced_const, top_inf_eq]
lemma
inducing_const_prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "induced_compose", "induced_const", "induced_inf", "inducing", "top_inf_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing_prod_const {b : β} {f : α → γ} : inducing (λ x, (f x, b)) ↔ inducing f
by simp_rw [inducing_iff, prod.topological_space, induced_inf, induced_compose, function.comp, induced_const, inf_top_eq]
lemma
inducing_prod_const
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "induced_compose", "induced_const", "induced_inf", "inducing", "inf_top_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding.prod_mk {f : α → β} {g : γ → δ} (hf : embedding f) (hg : embedding g) : embedding (λx:α×γ, (f x.1, g x.2))
{ inj := assume ⟨x₁, x₂⟩ ⟨y₁, y₂⟩, by simp; exact assume h₁ h₂, ⟨hf.inj h₁, hg.inj h₂⟩, ..hf.to_inducing.prod_mk hg.to_inducing }
lemma
embedding.prod_mk
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map.prod {f : α → β} {g : γ → δ} (hf : is_open_map f) (hg : is_open_map g) : is_open_map (λ p : α × γ, (f p.1, g p.2))
begin rw [is_open_map_iff_nhds_le], rintros ⟨a, b⟩, rw [nhds_prod_eq, nhds_prod_eq, ← filter.prod_map_map_eq], exact filter.prod_mono (hf.nhds_le a) (hg.nhds_le b) end
lemma
is_open_map.prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter.prod_map_map_eq", "filter.prod_mono", "is_open_map", "is_open_map_iff_nhds_le", "nhds_prod_eq" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
open_embedding.prod {f : α → β} {g : γ → δ} (hf : open_embedding f) (hg : open_embedding g) : open_embedding (λ x : α × γ, (f x.1, g x.2))
open_embedding_of_embedding_open (hf.1.prod_mk hg.1) (hf.is_open_map.prod hg.is_open_map)
lemma
open_embedding.prod
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "open_embedding", "open_embedding_of_embedding_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding_graph {f : α → β} (hf : continuous f) : embedding (λ x, (x, f x))
embedding_of_embedding_compose (continuous_id.prod_mk hf) continuous_fst embedding_id
lemma
embedding_graph
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_fst", "embedding", "embedding_id", "embedding_of_embedding_compose" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_inl : continuous (@inl α β)
continuous_sup_rng_left continuous_coinduced_rng
lemma
continuous_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_coinduced_rng", "continuous_sup_rng_left" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_inr : continuous (@inr α β)
continuous_sup_rng_right continuous_coinduced_rng
lemma
continuous_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_coinduced_rng", "continuous_sup_rng_right" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_sum_iff {s : set (α ⊕ β)} : is_open s ↔ is_open (inl ⁻¹' s) ∧ is_open (inr ⁻¹' s)
iff.rfl
lemma
is_open_sum_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map_inl : is_open_map (@inl α β)
λ u hu, by simpa [is_open_sum_iff, preimage_image_eq u sum.inl_injective]
lemma
is_open_map_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open_map", "is_open_sum_iff", "sum.inl_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map_inr : is_open_map (@inr α β)
λ u hu, by simpa [is_open_sum_iff, preimage_image_eq u sum.inr_injective]
lemma
is_open_map_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open_map", "is_open_sum_iff", "sum.inr_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
open_embedding_inl : open_embedding (@inl α β)
open_embedding_of_continuous_injective_open continuous_inl inl_injective is_open_map_inl
lemma
open_embedding_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_inl", "is_open_map_inl", "open_embedding", "open_embedding_of_continuous_injective_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
open_embedding_inr : open_embedding (@inr α β)
open_embedding_of_continuous_injective_open continuous_inr inr_injective is_open_map_inr
lemma
open_embedding_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_inr", "is_open_map_inr", "open_embedding", "open_embedding_of_continuous_injective_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding_inl : embedding (@inl α β)
open_embedding_inl.1
lemma
embedding_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding_inr : embedding (@inr α β)
open_embedding_inr.1
lemma
embedding_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_range_inl : is_open (range (inl : α → α ⊕ β))
open_embedding_inl.2
lemma
is_open_range_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_range_inr : is_open (range (inr : β → α ⊕ β))
open_embedding_inr.2
lemma
is_open_range_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed_range_inl : is_closed (range (inl : α → α ⊕ β))
by { rw [← is_open_compl_iff, compl_range_inl], exact is_open_range_inr }
lemma
is_closed_range_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_closed", "is_open_compl_iff", "is_open_range_inr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed_range_inr : is_closed (range (inr : β → α ⊕ β))
by { rw [← is_open_compl_iff, compl_range_inr], exact is_open_range_inl }
lemma
is_closed_range_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_closed", "is_open_compl_iff", "is_open_range_inl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_embedding_inl : closed_embedding (inl : α → α ⊕ β)
⟨embedding_inl, is_closed_range_inl⟩
lemma
closed_embedding_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closed_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_embedding_inr : closed_embedding (inr : β → α ⊕ β)
⟨embedding_inr, is_closed_range_inr⟩
lemma
closed_embedding_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closed_embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_inl (x : α) : 𝓝 (inl x : α ⊕ β) = map inl (𝓝 x)
(open_embedding_inl.map_nhds_eq _).symm
lemma
nhds_inl
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_inr (x : β) : 𝓝 (inr x : α ⊕ β) = map inr (𝓝 x)
(open_embedding_inr.map_nhds_eq _).symm
lemma
nhds_inr
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_sum_dom {f : α ⊕ β → γ} : continuous f ↔ continuous (f ∘ sum.inl) ∧ continuous (f ∘ sum.inr)
by simp only [continuous_sup_dom, continuous_coinduced_dom]
theorem
continuous_sum_dom
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_coinduced_dom", "continuous_sup_dom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_sum_elim {f : α → γ} {g : β → γ} : continuous (sum.elim f g) ↔ continuous f ∧ continuous g
continuous_sum_dom
lemma
continuous_sum_elim
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_sum_dom", "sum.elim" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.sum_elim {f : α → γ} {g : β → γ} (hf : continuous f) (hg : continuous g) : continuous (sum.elim f g)
continuous_sum_elim.2 ⟨hf, hg⟩
lemma
continuous.sum_elim
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "sum.elim" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_sum_map {f : α → β} {g : γ → δ} : continuous (sum.map f g) ↔ continuous f ∧ continuous g
continuous_sum_elim.trans $ embedding_inl.continuous_iff.symm.and embedding_inr.continuous_iff.symm
lemma
continuous_sum_map
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "sum.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.sum_map {f : α → β} {g : γ → δ} (hf : continuous f) (hg : continuous g) : continuous (sum.map f g)
continuous_sum_map.2 ⟨hf, hg⟩
lemma
continuous.sum_map
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "sum.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map_sum {f : α ⊕ β → γ} : is_open_map f ↔ is_open_map (λ a, f (inl a)) ∧ is_open_map (λ b, f (inr b))
by simp only [is_open_map_iff_nhds_le, sum.forall, nhds_inl, nhds_inr, filter.map_map]
lemma
is_open_map_sum
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter.map_map", "is_open_map", "is_open_map_iff_nhds_le", "nhds_inl", "nhds_inr" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map_sum_elim {f : α → γ} {g : β → γ} : is_open_map (sum.elim f g) ↔ is_open_map f ∧ is_open_map g
by simp only [is_open_map_sum, elim_inl, elim_inr]
lemma
is_open_map_sum_elim
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open_map", "is_open_map_sum", "sum.elim" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map.sum_elim {f : α → γ} {g : β → γ} (hf : is_open_map f) (hg : is_open_map g) : is_open_map (sum.elim f g)
is_open_map_sum_elim.2 ⟨hf, hg⟩
lemma
is_open_map.sum_elim
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open_map", "sum.elim" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing_coe {b : set β} : inducing (coe : b → β)
⟨rfl⟩
lemma
inducing_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "inducing" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing.of_cod_restrict {f : α → β} {b : set β} (hb : ∀ a, f a ∈ b) (h : inducing (b.cod_restrict f hb)) : inducing f
inducing_coe.comp h
lemma
inducing.of_cod_restrict
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "inducing" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding_subtype_coe : embedding (coe : subtype p → α)
⟨⟨rfl⟩, subtype.coe_injective⟩
lemma
embedding_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "embedding" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closed_embedding_subtype_coe (h : is_closed {a | p a}) : closed_embedding (coe : subtype p → α)
⟨embedding_subtype_coe, by rwa [subtype.range_coe_subtype]⟩
lemma
closed_embedding_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closed_embedding", "is_closed", "subtype.range_coe_subtype" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_subtype_val : continuous (@subtype.val α p)
continuous_induced_dom
lemma
continuous_subtype_val
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_induced_dom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_subtype_coe : continuous (coe : subtype p → α)
continuous_subtype_val
lemma
continuous_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_subtype_val" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.subtype_coe {f : β → subtype p} (hf : continuous f) : continuous (λ x, (f x : α))
continuous_subtype_coe.comp hf
lemma
continuous.subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open.open_embedding_subtype_coe {s : set α} (hs : is_open s) : open_embedding (coe : s → α)
{ induced := rfl, inj := subtype.coe_injective, open_range := (subtype.range_coe : range coe = s).symm ▸ hs }
lemma
is_open.open_embedding_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "open_embedding", "subtype.coe_injective", "subtype.range_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open.is_open_map_subtype_coe {s : set α} (hs : is_open s) : is_open_map (coe : s → α)
hs.open_embedding_subtype_coe.is_open_map
lemma
is_open.is_open_map_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "is_open_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_open_map.restrict {f : α → β} (hf : is_open_map f) {s : set α} (hs : is_open s) : is_open_map (s.restrict f)
hf.comp hs.is_open_map_subtype_coe
lemma
is_open_map.restrict
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "is_open", "is_open_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_closed.closed_embedding_subtype_coe {s : set α} (hs : is_closed s) : closed_embedding (coe : {x // x ∈ s} → α)
{ induced := rfl, inj := subtype.coe_injective, closed_range := (subtype.range_coe : range coe = s).symm ▸ hs }
lemma
is_closed.closed_embedding_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closed_embedding", "is_closed", "subtype.coe_injective", "subtype.range_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.subtype_mk {f : β → α} (h : continuous f) (hp : ∀x, p (f x)) : continuous (λx, (⟨f x, hp x⟩ : subtype p))
continuous_induced_rng.2 h
lemma
continuous.subtype_mk
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.subtype_map {f : α → β} (h : continuous f) {q : β → Prop} (hpq : ∀ x, p x → q (f x)) : continuous (subtype.map f hpq)
(h.comp continuous_subtype_coe).subtype_mk _
lemma
continuous.subtype_map
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous", "continuous_subtype_coe", "subtype.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_inclusion {s t : set α} (h : s ⊆ t) : continuous (inclusion h)
continuous_id.subtype_map h
lemma
continuous_inclusion
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_subtype_coe {p : α → Prop} {a : subtype p} : continuous_at (coe : subtype p → α) a
continuous_iff_continuous_at.mp continuous_subtype_coe _
lemma
continuous_at_subtype_coe
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at", "continuous_subtype_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subtype.dense_iff {s : set α} {t : set s} : dense t ↔ s ⊆ closure (coe '' t)
by { rw [inducing_coe.dense_iff, set_coe.forall], refl }
lemma
subtype.dense_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure", "dense", "set_coe.forall" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_nhds_subtype_coe_eq {a : α} (ha : p a) (h : {a | p a} ∈ 𝓝 a) : map (coe : subtype p → α) (𝓝 ⟨a, ha⟩) = 𝓝 a
map_nhds_induced_of_mem $ by simpa only [subtype.coe_mk, subtype.range_coe] using h
lemma
map_nhds_subtype_coe_eq
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "map_nhds_induced_of_mem", "subtype.coe_mk", "subtype.range_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nhds_subtype_eq_comap {a : α} {h : p a} : 𝓝 (⟨a, h⟩ : subtype p) = comap coe (𝓝 a)
nhds_induced _ _
lemma
nhds_subtype_eq_comap
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "nhds_induced" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
tendsto_subtype_rng {β : Type*} {p : α → Prop} {b : filter β} {f : β → subtype p} : ∀{a:subtype p}, tendsto f b (𝓝 a) ↔ tendsto (λx, (f x : α)) b (𝓝 (a : α))
| ⟨a, ha⟩ := by rw [nhds_subtype_eq_comap, tendsto_comap_iff, subtype.coe_mk]
lemma
tendsto_subtype_rng
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "filter", "nhds_subtype_eq_comap", "subtype.coe_mk" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
closure_subtype {x : {a // p a}} {s : set {a // p a}}: x ∈ closure s ↔ (x : α) ∈ closure ((coe : _ → α) '' s)
closure_induced
lemma
closure_subtype
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "closure", "closure_induced" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at_cod_restrict_iff {f : α → β} {t : set β} (h1 : ∀ x, f x ∈ t) {x : α} : continuous_at (cod_restrict f t h1) x ↔ continuous_at f x
by simp_rw [inducing_coe.continuous_at_iff, function.comp, coe_cod_restrict_apply]
lemma
continuous_at_cod_restrict_iff
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at.restrict {f : α → β} {s : set α} {t : set β} (h1 : maps_to f s t) {x : s} (h2 : continuous_at f x) : continuous_at (h1.restrict f s t) x
(h2.comp continuous_at_subtype_coe).cod_restrict _
lemma
continuous_at.restrict
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at", "continuous_at_subtype_coe" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous_at.restrict_preimage {f : α → β} {s : set β} {x : f ⁻¹' s} (h : continuous_at f x) : continuous_at (s.restrict_preimage f) x
h.restrict _
lemma
continuous_at.restrict_preimage
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_at" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
continuous.cod_restrict {f : α → β} {s : set β} (hf : continuous f) (hs : ∀ a, f a ∈ s) : continuous (s.cod_restrict f hs)
hf.subtype_mk hs
lemma
continuous.cod_restrict
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inducing.cod_restrict {e : α → β} (he : inducing e) {s : set β} (hs : ∀ x, e x ∈ s) : inducing (cod_restrict e s hs)
inducing_of_inducing_compose (he.continuous.cod_restrict hs) continuous_subtype_coe he
lemma
inducing.cod_restrict
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_subtype_coe", "inducing", "inducing_of_inducing_compose" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding.cod_restrict {e : α → β} (he : embedding e) (s : set β) (hs : ∀ x, e x ∈ s) : embedding (cod_restrict e s hs)
embedding_of_embedding_compose (he.continuous.cod_restrict hs) continuous_subtype_coe he
lemma
embedding.cod_restrict
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "continuous_subtype_coe", "embedding", "embedding_of_embedding_compose" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
embedding_inclusion {s t : set α} (h : s ⊆ t) : embedding (set.inclusion h)
embedding_subtype_coe.cod_restrict _ _
lemma
embedding_inclusion
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "embedding", "set.inclusion" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
discrete_topology.of_subset {X : Type*} [topological_space X] {s t : set X} (ds : discrete_topology s) (ts : t ⊆ s) : discrete_topology t
(embedding_inclusion ts).discrete_topology
lemma
discrete_topology.of_subset
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "discrete_topology", "embedding_inclusion", "topological_space" ]
Let `s, t ⊆ X` be two subsets of a topological space `X`. If `t ⊆ s` and the topology induced by `X`on `s` is discrete, then also the topology induces on `t` is discrete.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quotient_map_quot_mk : quotient_map (@quot.mk α r)
⟨quot.exists_rep, rfl⟩
lemma
quotient_map_quot_mk
topology
src/topology/constructions.lean
[ "topology.maps", "order.filter.pi" ]
[ "quotient_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83