order.filter.lift - mathlib docs

@[protected]

def filter.lift {α : Type u_1} {β : Type u_2} (f : filter α) (g : set α → filter β) :

A variant on bind using a function g taking a set instead of a member of α. This is essentially a push-forward along a function mapping each set to a filter.

Equations

f.lift g = ⨅ (s : set α) (H : s ∈ f), g s

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@[simp]

theorem filter.lift_top {α : Type u_1} {β : Type u_2} (g : set α → filter β) :

⊤.lift g = g set.univ

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theorem filter.has_basis.mem_lift_iff {α : Type u_1} {γ : Type u_3} {ι : Sort u_2} {p : ι → Prop} {s : ι → set α} {f : filter α} (hf : f.has_basis p s) {β : ι → Type u_4} {pg : Π (i : ι), β i → Prop} {sg : Π (i : ι), β i → set γ} {g : set α → filter γ} (hg : ∀ (i : ι), (g (s i)).has_basis (pg i) (sg i)) (gm : monotone g) {s_1 : set γ} :

s_1 ∈ f.lift g ↔ ∃ (i : ι) (hi : p i) (x : β i) (hx : pg i x), sg i x ⊆ s_1

If (p : ι → Prop, s : ι → set α) is a basis of a filter f, g is a monotone function set α → filter γ, and for each i, (pg : β i → Prop, sg : β i → set α) is a basis of the filter g (s i), then (λ (i : ι) (x : β i), p i ∧ pg i x, λ (i : ι) (x : β i), sg i x) is a basis of the filter f.lift g.

This basis is parametrized by i : ι and x : β i, so in order to formulate this fact using has_basis one has to use Σ i, β i as the index type, see filter.has_basis.lift. This lemma states the corresponding mem_iff statement without using a sigma type.

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theorem filter.has_basis.lift {α : Type u_1} {γ : Type u_3} {ι : Type u_2} {p : ι → Prop} {s : ι → set α} {f : filter α} (hf : f.has_basis p s) {β : ι → Type u_4} {pg : Π (i : ι), β i → Prop} {sg : Π (i : ι), β i → set γ} {g : set α → filter γ} (hg : ∀ (i : ι), (g (s i)).has_basis (pg i) (sg i)) (gm : monotone g) :

(f.lift g).has_basis (λ (i : Σ (i : ι), β i), p i.fst ∧ pg i.fst i.snd) (λ (i : Σ (i : ι), β i), sg i.fst i.snd)

If (p : ι → Prop, s : ι → set α) is a basis of a filter f, g is a monotone function set α → filter γ, and for each i, (pg : β i → Prop, sg : β i → set α) is a basis of the filter g (s i), then (λ (i : ι) (x : β i), p i ∧ pg i x, λ (i : ι) (x : β i), sg i x) is a basis of the filter f.lift g.

This basis is parametrized by i : ι and x : β i, so in order to formulate this fact using has_basis one has to use Σ i, β i as the index type. See also filter.has_basis.mem_lift_iff for the corresponding mem_iff statement formulated without using a sigma type.

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theorem filter.mem_lift_sets {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → filter β} (hg : monotone g) {s : set β} :

s ∈ f.lift g ↔ ∃ (t : set α) (H : t ∈ f), s ∈ g t

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theorem filter.mem_lift {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → filter β} {s : set β} {t : set α} (ht : t ∈ f) (hs : s ∈ g t) :

s ∈ f.lift g

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theorem filter.lift_le {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → filter β} {h : filter β} {s : set α} (hs : s ∈ f) (hg : g s ≤ h) :

f.lift g ≤ h

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theorem filter.le_lift {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → filter β} {h : filter β} (hh : ∀ (s : set α), s ∈ f → h ≤ g s) :

h ≤ f.lift g

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theorem filter.lift_mono {α : Type u_1} {β : Type u_2} {f₁ f₂ : filter α} {g₁ g₂ : set α → filter β} (hf : f₁ ≤ f₂) (hg : g₁ ≤ g₂) :

f₁.lift g₁ ≤ f₂.lift g₂

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theorem filter.lift_mono' {α : Type u_1} {β : Type u_2} {f : filter α} {g₁ g₂ : set α → filter β} (hg : ∀ (s : set α), s ∈ f → g₁ s ≤ g₂ s) :

f.lift g₁ ≤ f.lift g₂

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theorem filter.tendsto_lift {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → filter β} {m : γ → β} {l : filter γ} :

filter.tendsto m l (f.lift g) ↔ ∀ (s : set α), s ∈ f → filter.tendsto m l (g s)

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theorem filter.map_lift_eq {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → filter β} {m : β → γ} (hg : monotone g) :

filter.map m (f.lift g) = f.lift (filter.map m ∘ g)

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theorem filter.comap_lift_eq {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → filter β} {m : γ → β} (hg : monotone g) :

filter.comap m (f.lift g) = f.lift (filter.comap m ∘ g)

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theorem filter.comap_lift_eq2 {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {m : β → α} {g : set β → filter γ} (hg : monotone g) :

(filter.comap m f).lift g = f.lift (g ∘ set.preimage m)

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theorem filter.map_lift_eq2 {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set β → filter γ} {m : α → β} (hg : monotone g) :

(filter.map m f).lift g = f.lift (g ∘ set.image m)

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theorem filter.lift_comm {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : filter β} {h : set α → set β → filter γ} :

f.lift (λ (s : set α), g.lift (h s)) = g.lift (λ (t : set β), f.lift (λ (s : set α), h s t))

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theorem filter.lift_assoc {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → filter β} {h : set β → filter γ} (hg : monotone g) :

(f.lift g).lift h = f.lift (λ (s : set α), (g s).lift h)

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theorem filter.lift_lift_same_le_lift {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → set α → filter β} :

f.lift (λ (s : set α), f.lift (g s)) ≤ f.lift (λ (s : set α), g s s)

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theorem filter.lift_lift_same_eq_lift {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → set α → filter β} (hg₁ : ∀ (s : set α), monotone (λ (t : set α), g s t)) (hg₂ : ∀ (t : set α), monotone (λ (s : set α), g s t)) :

f.lift (λ (s : set α), f.lift (g s)) = f.lift (λ (s : set α), g s s)

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theorem filter.lift_principal {α : Type u_1} {β : Type u_2} {g : set α → filter β} {s : set α} (hg : monotone g) :

(𝓟 s).lift g = g s

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theorem filter.monotone_lift {α : Type u_1} {β : Type u_2} {γ : Type u_3} [preorder γ] {f : γ → filter α} {g : γ → set α → filter β} (hf : monotone f) (hg : monotone g) :

monotone (λ (c : γ), (f c).lift (g c))

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theorem filter.lift_ne_bot_iff {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → filter β} (hm : monotone g) :

(f.lift g).ne_bot ↔ ∀ (s : set α), s ∈ f → (g s).ne_bot

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@[simp]

theorem filter.lift_const {α : Type u_1} {β : Type u_2} {f : filter α} {g : filter β} :

f.lift (λ (x : set α), g) = g

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@[simp]

theorem filter.lift_inf {α : Type u_1} {β : Type u_2} {f : filter α} {g h : set α → filter β} :

f.lift (λ (x : set α), g x ⊓ h x) = f.lift g ⊓ f.lift h

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@[simp]

theorem filter.lift_principal2 {α : Type u_1} {f : filter α} :

f.lift 𝓟 = f

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theorem filter.lift_infi {α : Type u_1} {β : Type u_2} {ι : Sort u_4} {f : ι → filter α} {g : set α → filter β} [hι : nonempty ι] (hg : ∀ {s t : set α}, g s ⊓ g t = g (s ∩ t)) :

(infi f).lift g = ⨅ (i : ι), (f i).lift g

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@[protected]

def filter.lift' {α : Type u_1} {β : Type u_2} (f : filter α) (h : set α → set β) :

filter β

Specialize lift to functions set α → set β. This can be viewed as a generalization of map. This is essentially a push-forward along a function mapping each set to a set.

Equations

f.lift' h = f.lift (𝓟 ∘ h)

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@[simp]

theorem filter.lift'_top {α : Type u_1} {β : Type u_2} (h : set α → set β) :

⊤.lift' h = 𝓟 (h set.univ)

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theorem filter.mem_lift' {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} {t : set α} (ht : t ∈ f) :

h t ∈ f.lift' h

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theorem filter.tendsto_lift' {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {h : set α → set β} {m : γ → β} {l : filter γ} :

filter.tendsto m l (f.lift' h) ↔ ∀ (s : set α), s ∈ f → (∀ᶠ (a : γ) in l, m a ∈ h s)

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theorem filter.has_basis.lift' {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} {ι : Sort u_3} {p : ι → Prop} {s : ι → set α} (hf : f.has_basis p s) (hh : monotone h) :

(f.lift' h).has_basis p (h ∘ s)

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theorem filter.mem_lift'_sets {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} (hh : monotone h) {s : set β} :

s ∈ f.lift' h ↔ ∃ (t : set α) (H : t ∈ f), h t ⊆ s

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theorem filter.eventually_lift'_iff {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} (hh : monotone h) {p : β → Prop} :

(∀ᶠ (y : β) in f.lift' h, p y) ↔ ∃ (t : set α) (H : t ∈ f), ∀ (y : β), y ∈ h t → p y

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theorem filter.lift'_le {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → set β} {h : filter β} {s : set α} (hs : s ∈ f) (hg : 𝓟 (g s) ≤ h) :

f.lift' g ≤ h

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theorem filter.lift'_mono {α : Type u_1} {β : Type u_2} {f₁ f₂ : filter α} {h₁ h₂ : set α → set β} (hf : f₁ ≤ f₂) (hh : h₁ ≤ h₂) :

f₁.lift' h₁ ≤ f₂.lift' h₂

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theorem filter.lift'_mono' {α : Type u_1} {β : Type u_2} {f : filter α} {h₁ h₂ : set α → set β} (hh : ∀ (s : set α), s ∈ f → h₁ s ⊆ h₂ s) :

f.lift' h₁ ≤ f.lift' h₂

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theorem filter.lift'_cong {α : Type u_1} {β : Type u_2} {f : filter α} {h₁ h₂ : set α → set β} (hh : ∀ (s : set α), s ∈ f → h₁ s = h₂ s) :

f.lift' h₁ = f.lift' h₂

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theorem filter.map_lift'_eq {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {h : set α → set β} {m : β → γ} (hh : monotone h) :

filter.map m (f.lift' h) = f.lift' (set.image m ∘ h)

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theorem filter.map_lift'_eq2 {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set β → set γ} {m : α → β} (hg : monotone g) :

(filter.map m f).lift' g = f.lift' (g ∘ set.image m)

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theorem filter.comap_lift'_eq {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {h : set α → set β} {m : γ → β} (hh : monotone h) :

filter.comap m (f.lift' h) = f.lift' (set.preimage m ∘ h)

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theorem filter.comap_lift'_eq2 {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {m : β → α} {g : set β → set γ} (hg : monotone g) :

(filter.comap m f).lift' g = f.lift' (g ∘ set.preimage m)

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theorem filter.lift'_principal {α : Type u_1} {β : Type u_2} {h : set α → set β} {s : set α} (hh : monotone h) :

(𝓟 s).lift' h = 𝓟 (h s)

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theorem filter.lift'_pure {α : Type u_1} {β : Type u_2} {h : set α → set β} {a : α} (hh : monotone h) :

(pure a).lift' h = 𝓟 (h {a})

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theorem filter.lift'_bot {α : Type u_1} {β : Type u_2} {h : set α → set β} (hh : monotone h) :

⊥.lift' h = 𝓟 (h ∅)

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theorem filter.principal_le_lift' {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} {t : set β} (hh : ∀ (s : set α), s ∈ f → t ⊆ h s) :

𝓟 t ≤ f.lift' h

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theorem filter.monotone_lift' {α : Type u_1} {β : Type u_2} {γ : Type u_3} [preorder γ] {f : γ → filter α} {g : γ → set α → set β} (hf : monotone f) (hg : monotone g) :

monotone (λ (c : γ), (f c).lift' (g c))

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theorem filter.lift_lift'_assoc {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → set β} {h : set β → filter γ} (hg : monotone g) (hh : monotone h) :

(f.lift' g).lift h = f.lift (λ (s : set α), h (g s))

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theorem filter.lift'_lift'_assoc {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → set β} {h : set β → set γ} (hg : monotone g) (hh : monotone h) :

(f.lift' g).lift' h = f.lift' (λ (s : set α), h (g s))

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theorem filter.lift'_lift_assoc {α : Type u_1} {β : Type u_2} {γ : Type u_3} {f : filter α} {g : set α → filter β} {h : set β → set γ} (hg : monotone g) :

(f.lift g).lift' h = f.lift (λ (s : set α), (g s).lift' h)

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theorem filter.lift_lift'_same_le_lift' {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → set α → set β} :

f.lift (λ (s : set α), f.lift' (g s)) ≤ f.lift' (λ (s : set α), g s s)

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theorem filter.lift_lift'_same_eq_lift' {α : Type u_1} {β : Type u_2} {f : filter α} {g : set α → set α → set β} (hg₁ : ∀ (s : set α), monotone (λ (t : set α), g s t)) (hg₂ : ∀ (t : set α), monotone (λ (s : set α), g s t)) :

f.lift (λ (s : set α), f.lift' (g s)) = f.lift' (λ (s : set α), g s s)

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theorem filter.lift'_inf_principal_eq {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} {s : set β} :

f.lift' h ⊓ 𝓟 s = f.lift' (λ (t : set α), h t ∩ s)

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theorem filter.lift'_ne_bot_iff {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} (hh : monotone h) :

(f.lift' h).ne_bot ↔ ∀ (s : set α), s ∈ f → (h s).nonempty

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@[simp]

theorem filter.lift'_id {α : Type u_1} {f : filter α} :

f.lift' id = f

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theorem filter.le_lift' {α : Type u_1} {β : Type u_2} {f : filter α} {h : set α → set β} {g : filter β} (h_le : ∀ (s : set α), s ∈ f → h s ∈ g) :

g ≤ f.lift' h

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theorem filter.lift_infi' {α : Type u_1} {β : Type u_2} {ι : Sort u_4} {f : ι → filter α} {g : set α → filter β} [nonempty ι] (hf : directed ge f) (hg : monotone g) :

(infi f).lift g = ⨅ (i : ι), (f i).lift g

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theorem filter.lift'_infi {α : Type u_1} {β : Type u_2} {ι : Sort u_4} {f : ι → filter α} {g : set α → set β} [nonempty ι] (hg : ∀ {s t : set α}, g s ∩ g t = g (s ∩ t)) :

(infi f).lift' g = ⨅ (i : ι), (f i).lift' g

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theorem filter.lift'_inf {α : Type u_1} {β : Type u_2} (f g : filter α) {s : set α → set β} (hs : ∀ {t₁ t₂ : set α}, s t₁ ∩ s t₂ = s (t₁ ∩ t₂)) :

(f ⊓ g).lift' s = f.lift' s ⊓ g.lift' s

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theorem filter.comap_eq_lift' {α : Type u_1} {β : Type u_2} {f : filter β} {m : α → β} :

filter.comap m f = f.lift' (set.preimage m)

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theorem filter.lift'_infi_powerset {α : Type u_1} {ι : Sort u_4} {f : ι → filter α} :

(infi f).lift' set.powerset = ⨅ (i : ι), (f i).lift' set.powerset

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theorem filter.lift'_inf_powerset {α : Type u_1} (f g : filter α) :

(f ⊓ g).lift' set.powerset = f.lift' set.powerset ⊓ g.lift' set.powerset

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theorem filter.eventually_lift'_powerset {α : Type u_1} {f : filter α} {p : set α → Prop} :

(∀ᶠ (s : set α) in f.lift' set.powerset, p s) ↔ ∃ (s : set α) (H : s ∈ f), ∀ (t : set α), t ⊆ s → p t

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theorem filter.eventually_lift'_powerset' {α : Type u_1} {f : filter α} {p : set α → Prop} (hp : ∀ ⦃s t : set α⦄, s ⊆ t → p t → p s) :

(∀ᶠ (s : set α) in f.lift' set.powerset, p s) ↔ ∃ (s : set α) (H : s ∈ f), p s

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@[protected, instance]

def filter.lift'_powerset_ne_bot {α : Type u_1} (f : filter α) :

(f.lift' set.powerset).ne_bot

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theorem filter.tendsto_lift'_powerset_mono {α : Type u_1} {β : Type u_2} {la : filter α} {lb : filter β} {s t : α → set β} (ht : filter.tendsto t la (lb.lift' set.powerset)) (hst : ∀ᶠ (x : α) in la, s x ⊆ t x) :

filter.tendsto s la (lb.lift' set.powerset)

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@[simp]

theorem filter.eventually_lift'_powerset_forall {α : Type u_1} {f : filter α} {p : α → Prop} :

(∀ᶠ (s : set α) in f.lift' set.powerset, ∀ (x : α), x ∈ s → p x) ↔ ∀ᶠ (x : α) in f, p x

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theorem filter.eventually.lift'_powerset {α : Type u_1} {f : filter α} {p : α → Prop} :

(∀ᶠ (x : α) in f, p x) → (∀ᶠ (s : set α) in f.lift' set.powerset, ∀ (x : α), x ∈ s → p x)

Alias of eventually_lift'_powerset_forall.

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theorem filter.eventually.of_lift'_powerset {α : Type u_1} {f : filter α} {p : α → Prop} :

(∀ᶠ (s : set α) in f.lift' set.powerset, ∀ (x : α), x ∈ s → p x) → (∀ᶠ (x : α) in f, p x)

Alias of eventually_lift'_powerset_forall.

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@[simp]

theorem filter.eventually_lift'_powerset_eventually {α : Type u_1} {f g : filter α} {p : α → Prop} :

(∀ᶠ (s : set α) in f.lift' set.powerset, ∀ᶠ (x : α) in g, x ∈ s → p x) ↔ ∀ᶠ (x : α) in f ⊓ g, p x

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theorem filter.prod_def {α : Type u_1} {β : Type u_2} {f : filter α} {g : filter β} :

f ×ᶠ g = f.lift (λ (s : set α), g.lift' (λ (t : set β), s ×ˢ t))

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theorem filter.prod_same_eq {α : Type u_1} {f : filter α} :

f ×ᶠ f = f.lift' (λ (t : set α), t ×ˢ t)

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theorem filter.mem_prod_same_iff {α : Type u_1} {f : filter α} {s : set (α × α)} :

s ∈ f ×ᶠ f ↔ ∃ (t : set α) (H : t ∈ f), t ×ˢ t ⊆ s

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theorem filter.tendsto_prod_self_iff {α : Type u_1} {β : Type u_2} {f : α × α → β} {x : filter α} {y : filter β} :

filter.tendsto f (x ×ᶠ x) y ↔ ∀ (W : set β), W ∈ y → (∃ (U : set α) (H : U ∈ x), ∀ (x x' : α), x ∈ U → x' ∈ U → f (x, x') ∈ W)

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theorem filter.prod_lift_lift {α₁ : Type u_5} {α₂ : Type u_6} {β₁ : Type u_7} {β₂ : Type u_8} {f₁ : filter α₁} {f₂ : filter α₂} {g₁ : set α₁ → filter β₁} {g₂ : set α₂ → filter β₂} (hg₁ : monotone g₁) (hg₂ : monotone g₂) :

f₁.lift g₁ ×ᶠ f₂.lift g₂ = f₁.lift (λ (s : set α₁), f₂.lift (λ (t : set α₂), g₁ s ×ᶠ g₂ t))

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theorem filter.prod_lift'_lift' {α₁ : Type u_5} {α₂ : Type u_6} {β₁ : Type u_7} {β₂ : Type u_8} {f₁ : filter α₁} {f₂ : filter α₂} {g₁ : set α₁ → set β₁} {g₂ : set α₂ → set β₂} (hg₁ : monotone g₁) (hg₂ : monotone g₂) :

f₁.lift' g₁ ×ᶠ f₂.lift' g₂ = f₁.lift (λ (s : set α₁), f₂.lift' (λ (t : set α₂), g₁ s ×ˢ g₂ t))

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Lift filters along filter and set functions #