Lattice operations on finsets

This file is concerned with folding binary lattice operations over finsets.

For the special case of maximum and minimum of a finset, see Max.lean.

See also Mathlib/Order/CompleteLattice/Finset.lean, which is instead concerned with how big lattice or set operations behave when indexed by a finset.

sup and inf

def Finset.sup {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] (s : Finset β) (f : β → α) : α

Supremum of a finite set: sup {a, b, c} f = f a ⊔ f b ⊔ f c

Equations

• s.sup f = Finset.fold (fun (x1 x2 : α) => x1 ⊔ x2) ⊥ f s

def Finset.inf {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] (s : Finset β) (f : β → α) : α

Infimum of a finite set: inf {a, b, c} f = f a ⊓ f b ⊓ f c

Equations

• s.inf f = Finset.fold (fun (x1 x2 : α) => x1 ⊓ x2) ⊤ f s

theorem Finset.sup_def {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} : s.sup f = (Multiset.map f s.val).sup

theorem Finset.inf_def {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} : s.inf f = (Multiset.map f s.val).inf

@[simp]

theorem Finset.sup_empty {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {f : β → α} : ∅.sup f = ⊥

@[simp]

theorem Finset.inf_empty {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {f : β → α} : ∅.inf f = ⊤

@[simp]

theorem Finset.sup_cons {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} {b : β} (h : b ∉ s) : (cons b s h).sup f = f b ⊔ s.sup f

@[simp]

theorem Finset.inf_cons {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} {b : β} (h : b ∉ s) : (cons b s h).inf f = f b ⊓ s.inf f

@[simp]

theorem Finset.sup_insert {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} [DecidableEq β] {b : β} : (insert b s).sup f = f b ⊔ s.sup f

@[simp]

theorem Finset.inf_insert {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} [DecidableEq β] {b : β} : (insert b s).inf f = f b ⊓ s.inf f

@[simp]

theorem Finset.sup_image {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [OrderBot α] [DecidableEq β] (s : Finset γ) (f : γ → β) (g : β → α) : (image f s).sup g = s.sup (g ∘ f)

@[simp]

theorem Finset.inf_image {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [OrderTop α] [DecidableEq β] (s : Finset γ) (f : γ → β) (g : β → α) : (image f s).inf g = s.inf (g ∘ f)

@[simp]

theorem Finset.sup_map {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [OrderBot α] (s : Finset γ) (f : γ ↪ β) (g : β → α) : (map f s).sup g = s.sup (g ∘ ⇑f)

@[simp]

theorem Finset.inf_map {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [OrderTop α] (s : Finset γ) (f : γ ↪ β) (g : β → α) : (map f s).inf g = s.inf (g ∘ ⇑f)

@[simp]

theorem Finset.sup_singleton {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {f : β → α} {b : β} : {b}.sup f = f b

@[simp]

theorem Finset.inf_singleton {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {f : β → α} {b : β} : {b}.inf f = f b

theorem Finset.sup_sup {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f g : β → α} : s.sup (f ⊔ g) = s.sup f ⊔ s.sup g

theorem Finset.inf_inf {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f g : β → α} : s.inf (f ⊓ g) = s.inf f ⊓ s.inf g

theorem Finset.sup_congr {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s₁ s₂ : Finset β} {f g : β → α} (hs : s₁ = s₂) (hfg : ∀ a ∈ s₂, f a = g a) : s₁.sup f = s₂.sup g

theorem Finset.inf_congr {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s₁ s₂ : Finset β} {f g : β → α} (hs : s₁ = s₂) (hfg : ∀ a ∈ s₂, f a = g a) : s₁.inf f = s₂.inf g

@[simp]

theorem map_finset_sup {F : Type u_1} {α : Type u_2} {β : Type u_3} {ι : Type u_5} [SemilatticeSup α] [OrderBot α] [SemilatticeSup β] [OrderBot β] [FunLike F α β] [SupBotHomClass F α β] (f : F) (s : Finset ι) (g : ι → α) : f (s.sup g) = s.sup (⇑f ∘ g)

@[simp]

theorem map_finset_inf {F : Type u_1} {α : Type u_2} {β : Type u_3} {ι : Type u_5} [SemilatticeInf α] [OrderTop α] [SemilatticeInf β] [OrderTop β] [FunLike F α β] [InfTopHomClass F α β] (f : F) (s : Finset ι) (g : ι → α) : f (s.inf g) = s.inf (⇑f ∘ g)

@[simp]

theorem Finset.sup_le_iff {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} {a : α} : s.sup f ≤ a ↔ ∀ b ∈ s, f b ≤ a

@[simp]

theorem Finset.le_inf_iff {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} {a : α} : a ≤ s.inf f ↔ ∀ b ∈ s, a ≤ f b

theorem Finset.sup_le {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} {a : α} : (∀ b ∈ s, f b ≤ a) → s.sup f ≤ a

Alias of the reverse direction of Finset.sup_le_iff.

theorem Finset.le_inf {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} {a : α} : (∀ b ∈ s, a ≤ f b) → a ≤ s.inf f

Alias of the reverse direction of Finset.le_inf_iff.

theorem Finset.sup_const_le {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {a : α} : (s.sup fun (x : β) => a) ≤ a

theorem Finset.le_inf_const {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {a : α} : a ≤ s.inf fun (x : β) => a

@[deprecated Finset.le_inf_const (since := "2026-03-25")]

theorem Finset.le_inf_const_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {a : α} : a ≤ s.inf fun (x : β) => a

Alias of Finset.le_inf_const.

theorem Finset.le_sup {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} {b : β} (hb : b ∈ s) : f b ≤ s.sup f

theorem Finset.inf_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} {b : β} (hb : b ∈ s) : s.inf f ≤ f b

theorem Finset.isLUB_sup {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} : IsLUB (f '' ↑s) (s.sup f)

theorem Finset.isGLB_inf {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} : IsGLB (f '' ↑s) (s.inf f)

theorem Finset.isLUB_sup_id {α : Type u_2} [SemilatticeSup α] [OrderBot α] {s : Finset α} : IsLUB (↑s) (s.sup id)

theorem Finset.isGLB_inf_id {α : Type u_2} [SemilatticeInf α] [OrderTop α] {s : Finset α} : IsGLB (↑s) (s.inf id)

theorem Finset.le_sup_of_le {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} {a : α} {b : β} (hb : b ∈ s) (h : a ≤ f b) : a ≤ s.sup f

theorem Finset.inf_le_of_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} {a : α} {b : β} (hb : b ∈ s) (h : f b ≤ a) : s.inf f ≤ a

theorem Finset.sup_union {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s₁ s₂ : Finset β} {f : β → α} [DecidableEq β] : (s₁ ∪ s₂).sup f = s₁.sup f ⊔ s₂.sup f

theorem Finset.inf_union {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s₁ s₂ : Finset β} {f : β → α} [DecidableEq β] : (s₁ ∪ s₂).inf f = s₁.inf f ⊓ s₂.inf f

theorem Finset.sup_const {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} (h : s.Nonempty) (c : α) : (s.sup fun (x : β) => c) = c

theorem Finset.inf_const {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} (h : s.Nonempty) (c : α) : (s.inf fun (x : β) => c) = c

@[simp]

theorem Finset.sup_bot {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] (s : Finset β) : (s.sup fun (x : β) => ⊥) = ⊥

@[simp]

theorem Finset.inf_top {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] (s : Finset β) : (s.inf fun (x : β) => ⊤) = ⊤

theorem Finset.sup_ite {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f g : β → α} (p : β → Prop) [DecidablePred p] : (s.sup fun (i : β) => if p i then f i else g i) = (filter p s).sup f ⊔ {i ∈ s | ¬p i}.sup g

theorem Finset.inf_ite {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f g : β → α} (p : β → Prop) [DecidablePred p] : (s.inf fun (i : β) => if p i then f i else g i) = (filter p s).inf f ⊓ {i ∈ s | ¬p i}.inf g

theorem Finset.sup_mono_fun {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f g : β → α} (h : ∀ b ∈ s, f b ≤ g b) : s.sup f ≤ s.sup g

theorem Finset.inf_mono_fun {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f g : β → α} (h : ∀ b ∈ s, g b ≤ f b) : s.inf g ≤ s.inf f

theorem Finset.sup_mono {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s₁ s₂ : Finset β} {f : β → α} (h : s₁ ⊆ s₂) : s₁.sup f ≤ s₂.sup f

theorem Finset.inf_mono {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s₁ s₂ : Finset β} {f : β → α} (h : s₁ ⊆ s₂) : s₂.inf f ≤ s₁.inf f

theorem Finset.sup_comm {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [OrderBot α] (s : Finset β) (t : Finset γ) (f : β → γ → α) : (s.sup fun (b : β) => t.sup (f b)) = t.sup fun (c : γ) => s.sup fun (b : β) => f b c

theorem Finset.inf_comm {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [OrderTop α] (s : Finset β) (t : Finset γ) (f : β → γ → α) : (s.inf fun (b : β) => t.inf (f b)) = t.inf fun (c : γ) => s.inf fun (b : β) => f b c

@[simp]

theorem Finset.sup_attach {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] (s : Finset β) (f : β → α) : (s.attach.sup fun (x : ↥s) => f ↑x) = s.sup f

@[simp]

theorem Finset.inf_attach {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] (s : Finset β) (f : β → α) : (s.attach.inf fun (x : ↥s) => f ↑x) = s.inf f

@[simp]

theorem Finset.sup_erase_bot {α : Type u_2} [SemilatticeSup α] [OrderBot α] [DecidableEq α] (s : Finset α) : (s.erase ⊥).sup id = s.sup id

@[simp]

theorem Finset.inf_erase_top {α : Type u_2} [SemilatticeInf α] [OrderTop α] [DecidableEq α] (s : Finset α) : (s.erase ⊤).inf id = s.inf id

theorem Finset.sup_sdiff_right {α : Type u_7} {β : Type u_8} [GeneralizedBooleanAlgebra α] (s : Finset β) (f : β → α) (a : α) : (s.sup fun (b : β) => f b \ a) = s.sup f \ a

theorem Finset.apply_sup_eq_sup_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [OrderBot α] [SemilatticeSup γ] [OrderBot γ] {s : Finset β} {f : β → α} (g : α → γ) (g_sup : ∀ (x y : α), g (x ⊔ y) = g x ⊔ g y) (bot : g ⊥ = ⊥) : g (s.sup f) = s.sup (g ∘ f)

theorem Finset.apply_inf_eq_inf_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [OrderTop α] [SemilatticeInf γ] [OrderTop γ] {s : Finset β} {f : β → α} (g : α → γ) (g_inf : ∀ (x y : α), g (x ⊓ y) = g x ⊓ g y) (top : g ⊤ = ⊤) : g (s.inf f) = s.inf (g ∘ f)

@[deprecated Finset.apply_sup_eq_sup_comp (since := "2026-05-29")]

theorem Finset.comp_sup_eq_sup_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [OrderBot α] [SemilatticeSup γ] [OrderBot γ] {s : Finset β} {f : β → α} (g : α → γ) (g_sup : ∀ (x y : α), g (x ⊔ y) = g x ⊔ g y) (bot : g ⊥ = ⊥) : g (s.sup f) = s.sup (g ∘ f)

Alias of Finset.apply_sup_eq_sup_comp.

@[deprecated Finset.apply_inf_eq_inf_comp (since := "2026-05-29")]

theorem Finset.comp_inf_eq_inf_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [OrderTop α] [SemilatticeInf γ] [OrderTop γ] {s : Finset β} {f : β → α} (g : α → γ) (g_inf : ∀ (x y : α), g (x ⊓ y) = g x ⊓ g y) (top : g ⊤ = ⊤) : g (s.inf f) = s.inf (g ∘ f)

Alias of Finset.apply_inf_eq_inf_comp.

theorem Finset.sup_coe {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {P : α → Prop} {Pbot : P ⊥} {Psup : ∀ ⦃x y : α⦄, P x → P y → P (x ⊔ y)} (t : Finset β) (f : β → { x : α // P x }) : ↑(t.sup f) = t.sup fun (x : β) => ↑(f x)

Computing sup in a subtype (closed under sup) is the same as computing it in α.

theorem Finset.inf_coe {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {P : α → Prop} {Ptop : P ⊤} {Pinf : ∀ ⦃x y : α⦄, P x → P y → P (x ⊓ y)} (t : Finset β) (f : β → { x : α // P x }) : ↑(t.inf f) = t.inf fun (x : β) => ↑(f x)

Computing inf in a subtype (closed under inf) is the same as computing it in α.

@[simp]

theorem Finset.sup_toFinset {α : Type u_7} {β : Type u_8} [DecidableEq β] (s : Finset α) (f : α → Multiset β) : (s.sup f).toFinset = s.sup fun (x : α) => (f x).toFinset

theorem List.foldr_sup_eq_sup_toFinset {α : Type u_2} [SemilatticeSup α] [OrderBot α] [DecidableEq α] (l : List α) : foldr (fun (x1 x2 : α) => x1 ⊔ x2) ⊥ l = l.toFinset.sup id

theorem List.foldr_inf_eq_inf_toFinset {α : Type u_2} [SemilatticeInf α] [OrderTop α] [DecidableEq α] (l : List α) : foldr (fun (x1 x2 : α) => x1 ⊓ x2) ⊤ l = l.toFinset.inf id

theorem Finset.subset_range_sup_succ (s : Finset ℕ) : s ⊆ range (s.sup id).succ

theorem Finset.sup_induction {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} {p : α → Prop} (hb : p ⊥) (hp : ∀ (a₁ : α), p a₁ → ∀ (a₂ : α), p a₂ → p (a₁ ⊔ a₂)) (hs : ∀ b ∈ s, p (f b)) : p (s.sup f)

theorem Finset.inf_induction {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} {f : β → α} {p : α → Prop} (hb : p ⊤) (hp : ∀ (a₁ : α), p a₁ → ∀ (a₂ : α), p a₂ → p (a₁ ⊓ a₂)) (hs : ∀ b ∈ s, p (f b)) : p (s.inf f)

theorem Finset.sup_le_of_le_directed {α : Type u_7} [SemilatticeSup α] [OrderBot α] (s : Set α) (hs : s.Nonempty) (hdir : DirectedOn (fun (x1 x2 : α) => x1 ≤ x2) s) (t : Finset α) : (∀ x ∈ t, ∃ y ∈ s, x ≤ y) → ∃ x ∈ s, t.sup id ≤ x

theorem Finset.le_inf_of_directed_le {α : Type u_7} [SemilatticeInf α] [OrderTop α] (s : Set α) (hs : s.Nonempty) (hdir : DirectedOn (fun (x1 x2 : α) => x2 ≤ x1) s) (t : Finset α) : (∀ x ∈ t, ∃ y ∈ s, y ≤ x) → ∃ x ∈ s, x ≤ t.inf id

theorem Finset.sup_mem {α : Type u_2} [SemilatticeSup α] [OrderBot α] (s : Set α) (w₁ : ⊥ ∈ s) (w₂ : ∀ x ∈ s, ∀ y ∈ s, x ⊔ y ∈ s) {ι : Type u_7} (t : Finset ι) (p : ι → α) (h : ∀ i ∈ t, p i ∈ s) : t.sup p ∈ s

theorem Finset.inf_mem {α : Type u_2} [SemilatticeInf α] [OrderTop α] (s : Set α) (w₁ : ⊤ ∈ s) (w₂ : ∀ x ∈ s, ∀ y ∈ s, x ⊓ y ∈ s) {ι : Type u_7} (t : Finset ι) (p : ι → α) (h : ∀ i ∈ t, p i ∈ s) : t.inf p ∈ s

@[simp]

theorem Finset.sup_eq_bot_iff {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] (f : β → α) (S : Finset β) : S.sup f = ⊥ ↔ ∀ s ∈ S, f s = ⊥

@[simp]

theorem Finset.inf_eq_top_iff {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] (f : β → α) (S : Finset β) : S.inf f = ⊤ ↔ ∀ s ∈ S, f s = ⊤

@[simp]

theorem Finset.sup_eq_one {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} [One α] [IsBotOneClass α] : s.sup f = 1 ↔ ∀ i ∈ s, f i = 1

@[simp]

theorem Finset.sup_eq_zero {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} [Zero α] [IsBotZeroClass α] : s.sup f = 0 ↔ ∀ i ∈ s, f i = 0

@[simp]

theorem Finset.sup_disjSum {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [OrderBot α] (s : Finset β) (t : Finset γ) (f : β ⊕ γ → α) : (s.disjSum t).sup f = (s.sup fun (x : β) => f (Sum.inl x)) ⊔ t.sup fun (x : γ) => f (Sum.inr x)

@[simp]

theorem Finset.inf_disjSum {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [OrderTop α] (s : Finset β) (t : Finset γ) (f : β ⊕ γ → α) : (s.disjSum t).inf f = (s.inf fun (x : β) => f (Sum.inl x)) ⊓ t.inf fun (x : γ) => f (Sum.inr x)

@[simp]

theorem Finset.sup_eq_bot_of_isEmpty {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] [IsEmpty β] (f : β → α) (S : Finset β) : S.sup f = ⊥

@[simp]

theorem Finset.inf_eq_top_of_isEmpty {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] [IsEmpty β] (f : β → α) (S : Finset β) : S.inf f = ⊤

theorem Finset.le_sup_dite_pos {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} (p : β → Prop) [DecidablePred p] {f : (b : β) → p b → α} {g : (b : β) → ¬p b → α} {b : β} (h₀ : b ∈ s) (h₁ : p b) : f b h₁ ≤ s.sup fun (i : β) => if h : p i then f i h else g i h

theorem Finset.inf_dite_pos_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} (p : β → Prop) [DecidablePred p] {f : (b : β) → p b → α} {g : (b : β) → ¬p b → α} {b : β} (h₀ : b ∈ s) (h₁ : p b) : (s.inf fun (i : β) => if h : p i then f i h else g i h) ≤ f b h₁

theorem Finset.le_sup_dite_neg {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} (p : β → Prop) [DecidablePred p] {f : (b : β) → p b → α} {g : (b : β) → ¬p b → α} {b : β} (h₀ : b ∈ s) (h₁ : ¬p b) : g b h₁ ≤ s.sup fun (i : β) => if h : p i then f i h else g i h

theorem Finset.inf_dite_neg_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} (p : β → Prop) [DecidablePred p] {f : (b : β) → p b → α} {g : (b : β) → ¬p b → α} {b : β} (h₀ : b ∈ s) (h₁ : ¬p b) : (s.inf fun (i : β) => if h : p i then f i h else g i h) ≤ g b h₁

theorem Finset.sup_eq_iSup {α : Type u_2} {β : Type u_3} [CompleteLattice β] (s : Finset α) (f : α → β) : s.sup f = ⨆ a ∈ s, f a

theorem Finset.inf_eq_iInf {α : Type u_2} {β : Type u_3} [CompleteLattice β] (s : Finset α) (f : α → β) : s.inf f = ⨅ a ∈ s, f a

theorem Finset.sup_id_eq_sSup {α : Type u_2} [CompleteLattice α] (s : Finset α) : s.sup id = sSup ↑s

theorem Finset.inf_id_eq_sInf {α : Type u_2} [CompleteLattice α] (s : Finset α) : s.inf id = sInf ↑s

theorem Finset.sup_id_set_eq_sUnion {α : Type u_2} (s : Finset (Set α)) : s.sup id = ⋃₀ ↑s

theorem Finset.inf_id_set_eq_sInter {α : Type u_2} (s : Finset (Set α)) : s.inf id = ⋂₀ ↑s

@[simp]

theorem Finset.sup_set_eq_biUnion {α : Type u_2} {β : Type u_3} (s : Finset α) (f : α → Set β) : s.sup f = ⋃ x ∈ s, f x

@[simp]

theorem Finset.inf_set_eq_iInter {α : Type u_2} {β : Type u_3} (s : Finset α) (f : α → Set β) : s.inf f = ⋂ x ∈ s, f x

theorem Finset.sup_eq_sSup_image {α : Type u_2} {β : Type u_3} [CompleteLattice β] (s : Finset α) (f : α → β) : s.sup f = sSup (f '' ↑s)

theorem Finset.inf_eq_sInf_image {α : Type u_2} {β : Type u_3} [CompleteLattice β] (s : Finset α) (f : α → β) : s.inf f = sInf (f '' ↑s)

theorem Finset.exists_sup_ge {α : Type u_2} {β : Type u_3} [SemilatticeSup β] [OrderBot β] [WellFoundedGT β] (f : α → β) : ∃ (t : Finset α), ∀ (a : α), f a ≤ t.sup f

theorem Finset.exists_inf_le {α : Type u_2} {β : Type u_3} [SemilatticeInf β] [OrderTop β] [WellFoundedLT β] (f : α → β) : ∃ (t : Finset α), ∀ (a : α), t.inf f ≤ f a

theorem Finset.exists_sup_eq_iSup {α : Type u_2} {β : Type u_3} [CompleteLattice β] [WellFoundedGT β] (f : α → β) : ∃ (t : Finset α), t.sup f = ⨆ (a : α), f a

theorem Finset.exists_inf_eq_iInf {α : Type u_2} {β : Type u_3} [CompleteLattice β] [WellFoundedLT β] (f : α → β) : ∃ (t : Finset α), t.inf f = ⨅ (a : α), f a

@[simp]

theorem Finset.toDual_sup {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] (s : Finset β) (f : β → α) : OrderDual.toDual (s.sup f) = s.inf (⇑OrderDual.toDual ∘ f)

@[simp]

theorem Finset.toDual_inf {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] (s : Finset β) (f : β → α) : OrderDual.toDual (s.inf f) = s.sup (⇑OrderDual.toDual ∘ f)

@[simp]

theorem Finset.ofDual_sup {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] (s : Finset β) (f : β → αᵒᵈ) : OrderDual.ofDual (s.sup f) = s.inf (⇑OrderDual.ofDual ∘ f)

@[simp]

theorem Finset.ofDual_inf {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] (s : Finset β) (f : β → αᵒᵈ) : OrderDual.ofDual (s.inf f) = s.sup (⇑OrderDual.ofDual ∘ f)

theorem Finset.sup_inf_distrib_left {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderBot α] (s : Finset ι) (f : ι → α) (a : α) : a ⊓ s.sup f = s.sup fun (i : ι) => a ⊓ f i

theorem Finset.inf_sup_distrib_left {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderTop α] (s : Finset ι) (f : ι → α) (a : α) : a ⊔ s.inf f = s.inf fun (i : ι) => a ⊔ f i

theorem Finset.sup_inf_distrib_right {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderBot α] (s : Finset ι) (f : ι → α) (a : α) : s.sup f ⊓ a = s.sup fun (i : ι) => f i ⊓ a

theorem Finset.inf_sup_distrib_right {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderTop α] (s : Finset ι) (f : ι → α) (a : α) : s.inf f ⊔ a = s.inf fun (i : ι) => f i ⊔ a

theorem Finset.disjoint_sup_right {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderBot α] {s : Finset ι} {f : ι → α} {a : α} : Disjoint a (s.sup f) ↔ ∀ ⦃i : ι⦄, i ∈ s → Disjoint a (f i)

theorem Finset.codisjoint_inf_right {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderTop α] {s : Finset ι} {f : ι → α} {a : α} : Codisjoint a (s.inf f) ↔ ∀ ⦃i : ι⦄, i ∈ s → Codisjoint a (f i)

theorem Finset.disjoint_sup_left {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderBot α] {s : Finset ι} {f : ι → α} {a : α} : Disjoint (s.sup f) a ↔ ∀ ⦃i : ι⦄, i ∈ s → Disjoint (f i) a

theorem Finset.codisjoint_inf_left {α : Type u_2} {ι : Type u_5} [DistribLattice α] [OrderTop α] {s : Finset ι} {f : ι → α} {a : α} : Codisjoint (s.inf f) a ↔ ∀ ⦃i : ι⦄, i ∈ s → Codisjoint (f i) a

theorem Finset.sup_sdiff_left {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] (s : Finset ι) (f : ι → α) (a : α) : (s.sup fun (b : ι) => a \ f b) = a \ s.inf f

theorem Finset.inf_sdiff_left {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : (s.inf fun (b : ι) => a \ f b) = a \ s.sup f

theorem Finset.inf_sdiff_right {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : (s.inf fun (b : ι) => f b \ a) = s.inf f \ a

theorem Finset.inf_himp_right {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] (s : Finset ι) (f : ι → α) (a : α) : (s.inf fun (b : ι) => f b ⇨ a) = s.sup f ⇨ a

theorem Finset.sup_himp_right {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : (s.sup fun (b : ι) => f b ⇨ a) = s.inf f ⇨ a

theorem Finset.sup_himp_left {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : (s.sup fun (b : ι) => a ⇨ f b) = a ⇨ s.sup f

@[simp]

theorem Finset.compl_sup {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] (s : Finset ι) (f : ι → α) : (s.sup f)ᶜ = s.inf fun (i : ι) => (f i)ᶜ

@[simp]

theorem Finset.compl_inf {α : Type u_2} {ι : Type u_5} [BooleanAlgebra α] (s : Finset ι) (f : ι → α) : (s.inf f)ᶜ = s.sup fun (i : ι) => (f i)ᶜ

theorem Finset.apply_sup_eq_sup_comp_of_linearOrder {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] [OrderBot α] {s : Finset ι} {f : ι → α} [SemilatticeSup β] [OrderBot β] (g : α → β) (mono_g : Monotone g) (bot : g ⊥ = ⊥) : g (s.sup f) = s.sup (g ∘ f)

theorem Finset.apply_inf_eq_inf_comp_of_linearOrder {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] [OrderTop α] {s : Finset ι} {f : ι → α} [SemilatticeInf β] [OrderTop β] (g : α → β) (mono_g : Monotone g) (top : g ⊤ = ⊤) : g (s.inf f) = s.inf (g ∘ f)

@[deprecated Finset.apply_sup_eq_sup_comp_of_linearOrder (since := "2026-05-29")]

theorem Finset.comp_sup_eq_sup_comp_of_is_total {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] [OrderBot α] {s : Finset ι} {f : ι → α} [SemilatticeSup β] [OrderBot β] (g : α → β) (mono_g : Monotone g) (bot : g ⊥ = ⊥) : g (s.sup f) = s.sup (g ∘ f)

Alias of Finset.apply_sup_eq_sup_comp_of_linearOrder.

@[deprecated Finset.apply_inf_eq_inf_comp_of_linearOrder (since := "2026-05-29")]

theorem Finset.comp_inf_eq_inf_comp_of_is_total {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] [OrderTop α] {s : Finset ι} {f : ι → α} [SemilatticeInf β] [OrderTop β] (g : α → β) (mono_g : Monotone g) (top : g ⊤ = ⊤) : g (s.inf f) = s.inf (g ∘ f)

Alias of Finset.apply_inf_eq_inf_comp_of_linearOrder.

@[simp]

theorem Finset.le_sup_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderBot α] {s : Finset ι} {f : ι → α} {a : α} (ha : ⊥ < a) : a ≤ s.sup f ↔ ∃ b ∈ s, a ≤ f b

@[simp]

theorem Finset.inf_le_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderTop α] {s : Finset ι} {f : ι → α} {a : α} (ha : a < ⊤) : s.inf f ≤ a ↔ ∃ b ∈ s, f b ≤ a

theorem Finset.sup_eq_top_iff {ι : Type u_5} {α : Type u_7} [LinearOrder α] [BoundedOrder α] [Nontrivial α] {s : Finset ι} {f : ι → α} : s.sup f = ⊤ ↔ ∃ b ∈ s, f b = ⊤

theorem Finset.inf_eq_bot_iff {ι : Type u_5} {α : Type u_7} [LinearOrder α] [BoundedOrder α] [Nontrivial α] {s : Finset ι} {f : ι → α} : s.inf f = ⊥ ↔ ∃ b ∈ s, f b = ⊥

theorem Finset.Nonempty.sup_eq_top_iff {ι : Type u_5} {α : Type u_7} [LinearOrder α] [BoundedOrder α] {s : Finset ι} {f : ι → α} (hs : s.Nonempty) : s.sup f = ⊤ ↔ ∃ b ∈ s, f b = ⊤

theorem Finset.Nonempty.inf_eq_bot_iff {ι : Type u_5} {α : Type u_7} [LinearOrder α] [BoundedOrder α] {s : Finset ι} {f : ι → α} (hs : s.Nonempty) : s.inf f = ⊥ ↔ ∃ b ∈ s, f b = ⊥

@[simp]

theorem Finset.lt_sup_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderBot α] {s : Finset ι} {f : ι → α} {a : α} : a < s.sup f ↔ ∃ b ∈ s, a < f b

@[simp]

theorem Finset.inf_lt_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderTop α] {s : Finset ι} {f : ι → α} {a : α} : s.inf f < a ↔ ∃ b ∈ s, f b < a

@[simp]

theorem Finset.sup_lt_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderBot α] {s : Finset ι} {f : ι → α} {a : α} (ha : ⊥ < a) : s.sup f < a ↔ ∀ b ∈ s, f b < a

@[simp]

theorem Finset.lt_inf_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderTop α] {s : Finset ι} {f : ι → α} {a : α} (ha : a < ⊤) : a < s.inf f ↔ ∀ b ∈ s, a < f b

theorem Finset.sup_mem_of_nonempty {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderBot α] {s : Finset ι} {f : ι → α} (hs : s.Nonempty) : s.sup f ∈ f '' ↑s

theorem Finset.inf_mem_of_nonempty {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderTop α] {s : Finset ι} {f : ι → α} (hs : s.Nonempty) : s.inf f ∈ f '' ↑s

theorem Finset.sup_of_mem {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (f : β → α) {b : β} (h : b ∈ s) : ∃ (a : α), s.sup (WithBot.some ∘ f) = ↑a

theorem Finset.inf_of_mem {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (f : β → α) {b : β} (h : b ∈ s) : ∃ (a : α), s.inf (WithTop.some ∘ f) = ↑a

def Finset.sup' {α : Type u_2} {β : Type u_3} [SemilatticeSup α] (s : Finset β) (H : s.Nonempty) (f : β → α) : α

Given nonempty finset s then s.sup' H f is the supremum of its image under f in (possibly unbounded) join-semilattice α, where H is a proof of nonemptiness. If α has a bottom element you may instead use Finset.sup which does not require s nonempty.

Equations

• s.sup' H f = (s.sup (WithBot.some ∘ f)).unbot ⋯

def Finset.inf' {α : Type u_2} {β : Type u_3} [SemilatticeInf α] (s : Finset β) (H : s.Nonempty) (f : β → α) : α

Given nonempty finset s then s.inf' H f is the infimum of its image under f in (possibly unbounded) meet-semilattice α, where H is a proof of nonemptiness. If α has a top element you may instead use Finset.inf which does not require s nonempty.

Equations

• s.inf' H f = (s.inf (WithTop.some ∘ f)).untop ⋯

@[simp]

theorem Finset.coe_sup' {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) : ↑(s.sup' H f) = s.sup (WithBot.some ∘ f)

@[simp]

theorem Finset.coe_inf' {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) : ↑(s.inf' H f) = s.inf (WithTop.some ∘ f)

@[simp]

theorem Finset.sup'_cons {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) {b : β} {hb : b ∉ s} : (cons b s hb).sup' ⋯ f = f b ⊔ s.sup' H f

@[simp]

theorem Finset.inf'_cons {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) {b : β} {hb : b ∉ s} : (cons b s hb).inf' ⋯ f = f b ⊓ s.inf' H f

@[simp]

theorem Finset.sup'_insert {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) [DecidableEq β] {b : β} : (insert b s).sup' ⋯ f = f b ⊔ s.sup' H f

@[simp]

theorem Finset.inf'_insert {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) [DecidableEq β] {b : β} : (insert b s).inf' ⋯ f = f b ⊓ s.inf' H f

@[simp]

theorem Finset.sup'_singleton {α : Type u_2} {β : Type u_3} [SemilatticeSup α] (f : β → α) {b : β} : {b}.sup' ⋯ f = f b

@[simp]

theorem Finset.inf'_singleton {α : Type u_2} {β : Type u_3} [SemilatticeInf α] (f : β → α) {b : β} : {b}.inf' ⋯ f = f b

@[simp]

theorem Finset.sup'_le_iff {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) {a : α} : s.sup' H f ≤ a ↔ ∀ b ∈ s, f b ≤ a

@[simp]

theorem Finset.le_inf'_iff {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) {a : α} : a ≤ s.inf' H f ↔ ∀ b ∈ s, a ≤ f b

theorem Finset.sup'_le {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) {a : α} : (∀ b ∈ s, f b ≤ a) → s.sup' H f ≤ a

Alias of the reverse direction of Finset.sup'_le_iff.

theorem Finset.le_inf' {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) {a : α} : (∀ b ∈ s, a ≤ f b) → a ≤ s.inf' H f

Alias of the reverse direction of Finset.le_inf'_iff.

theorem Finset.le_sup' {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (f : β → α) {b : β} (h : b ∈ s) : f b ≤ s.sup' ⋯ f

theorem Finset.inf'_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (f : β → α) {b : β} (h : b ∈ s) : s.inf' ⋯ f ≤ f b

theorem Finset.isLUB_sup' {α : Type u_2} [SemilatticeSup α] {s : Finset α} (hs : s.Nonempty) : IsLUB (↑s) (s.sup' hs id)

theorem Finset.isGLB_inf' {α : Type u_2} [SemilatticeInf α] {s : Finset α} (hs : s.Nonempty) : IsGLB (↑s) (s.inf' hs id)

theorem Finset.le_sup'_of_le {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (f : β → α) {a : α} {b : β} (hb : b ∈ s) (h : a ≤ f b) : a ≤ s.sup' ⋯ f

theorem Finset.inf'_le_of_le {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (f : β → α) {a : α} {b : β} (hb : b ∈ s) (h : f b ≤ a) : s.inf' ⋯ f ≤ a

theorem Finset.sup'_eq_of_forall {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) {a : α} (h : ∀ b ∈ s, f b = a) : s.sup' H f = a

theorem Finset.inf'_eq_of_forall {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) {a : α} (h : ∀ b ∈ s, f b = a) : s.inf' H f = a

@[simp]

theorem Finset.sup'_const {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (a : α) : (s.sup' H fun (x : β) => a) = a

@[simp]

theorem Finset.inf'_const {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (a : α) : (s.inf' H fun (x : β) => a) = a

theorem Finset.sup'_union {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [DecidableEq β] {s₁ s₂ : Finset β} (h₁ : s₁.Nonempty) (h₂ : s₂.Nonempty) (f : β → α) : (s₁ ∪ s₂).sup' ⋯ f = s₁.sup' h₁ f ⊔ s₂.sup' h₂ f

theorem Finset.inf'_union {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [DecidableEq β] {s₁ s₂ : Finset β} (h₁ : s₁.Nonempty) (h₂ : s₂.Nonempty) (f : β → α) : (s₁ ∪ s₂).inf' ⋯ f = s₁.inf' h₁ f ⊓ s₂.inf' h₂ f

theorem Finset.sup'_comm {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] {s : Finset β} {t : Finset γ} (hs : s.Nonempty) (ht : t.Nonempty) (f : β → γ → α) : (s.sup' hs fun (b : β) => t.sup' ht (f b)) = t.sup' ht fun (c : γ) => s.sup' hs fun (b : β) => f b c

theorem Finset.inf'_comm {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] {s : Finset β} {t : Finset γ} (hs : s.Nonempty) (ht : t.Nonempty) (f : β → γ → α) : (s.inf' hs fun (b : β) => t.inf' ht (f b)) = t.inf' ht fun (c : γ) => s.inf' hs fun (b : β) => f b c

theorem Finset.sup'_induction {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) (f : β → α) {p : α → Prop} (hp : ∀ (a₁ : α), p a₁ → ∀ (a₂ : α), p a₂ → p (a₁ ⊔ a₂)) (hs : ∀ b ∈ s, p (f b)) : p (s.sup' H f)

theorem Finset.inf'_induction {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) (f : β → α) {p : α → Prop} (hp : ∀ (a₁ : α), p a₁ → ∀ (a₂ : α), p a₂ → p (a₁ ⊓ a₂)) (hs : ∀ b ∈ s, p (f b)) : p (s.inf' H f)

theorem Finset.sup'_mem {α : Type u_2} [SemilatticeSup α] (s : Set α) (w : ∀ x ∈ s, ∀ y ∈ s, x ⊔ y ∈ s) {ι : Type u_7} (t : Finset ι) (H : t.Nonempty) (p : ι → α) (h : ∀ i ∈ t, p i ∈ s) : t.sup' H p ∈ s

theorem Finset.inf'_mem {α : Type u_2} [SemilatticeInf α] (s : Set α) (w : ∀ x ∈ s, ∀ y ∈ s, x ⊓ y ∈ s) {ι : Type u_7} (t : Finset ι) (H : t.Nonempty) (p : ι → α) (h : ∀ i ∈ t, p i ∈ s) : t.inf' H p ∈ s

theorem Finset.sup'_congr {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} (H : s.Nonempty) {t : Finset β} {f g : β → α} (h₁ : s = t) (h₂ : ∀ x ∈ s, f x = g x) : s.sup' H f = t.sup' ⋯ g

theorem Finset.inf'_congr {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} (H : s.Nonempty) {t : Finset β} {f g : β → α} (h₁ : s = t) (h₂ : ∀ x ∈ s, f x = g x) : s.inf' H f = t.inf' ⋯ g

theorem Finset.apply_sup'_eq_sup'_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [SemilatticeSup γ] {s : Finset β} (H : s.Nonempty) {f : β → α} (g : α → γ) (g_sup : ∀ (x y : α), g (x ⊔ y) = g x ⊔ g y) : g (s.sup' H f) = s.sup' H (g ∘ f)

theorem Finset.apply_inf'_eq_inf'_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [SemilatticeInf γ] {s : Finset β} (H : s.Nonempty) {f : β → α} (g : α → γ) (g_inf : ∀ (x y : α), g (x ⊓ y) = g x ⊓ g y) : g (s.inf' H f) = s.inf' H (g ∘ f)

@[deprecated Finset.apply_sup'_eq_sup'_comp (since := "2026-05-29")]

theorem Finset.comp_sup'_eq_sup'_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [SemilatticeSup γ] {s : Finset β} (H : s.Nonempty) {f : β → α} (g : α → γ) (g_sup : ∀ (x y : α), g (x ⊔ y) = g x ⊔ g y) : g (s.sup' H f) = s.sup' H (g ∘ f)

Alias of Finset.apply_sup'_eq_sup'_comp.

@[deprecated Finset.apply_sup'_eq_sup'_comp (since := "2026-05-29")]

theorem Finset.comp_inf'_eq_inf'_comp {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [SemilatticeSup γ] {s : Finset β} (H : s.Nonempty) {f : β → α} (g : α → γ) (g_sup : ∀ (x y : α), g (x ⊔ y) = g x ⊔ g y) : g (s.sup' H f) = s.sup' H (g ∘ f)

Alias of Finset.apply_sup'_eq_sup'_comp.

@[simp]

theorem map_finset_sup' {F : Type u_1} {α : Type u_2} {β : Type u_3} {ι : Type u_5} [SemilatticeSup α] [SemilatticeSup β] [FunLike F α β] [SupHomClass F α β] (f : F) {s : Finset ι} (hs : s.Nonempty) (g : ι → α) : f (s.sup' hs g) = s.sup' hs (⇑f ∘ g)

@[simp]

theorem map_finset_inf' {F : Type u_1} {α : Type u_2} {β : Type u_3} {ι : Type u_5} [SemilatticeInf α] [SemilatticeInf β] [FunLike F α β] [InfHomClass F α β] (f : F) {s : Finset ι} (hs : s.Nonempty) (g : ι → α) : f (s.inf' hs g) = s.inf' hs (⇑f ∘ g)

@[simp]

theorem Finset.sup'_image {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [DecidableEq β] {s : Finset γ} {f : γ → β} (hs : (image f s).Nonempty) (g : β → α) : (image f s).sup' hs g = s.sup' ⋯ (g ∘ f)

To rewrite from right to left, use Finset.sup'_comp_eq_image.

@[simp]

theorem Finset.inf'_image {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [DecidableEq β] {s : Finset γ} {f : γ → β} (hs : (image f s).Nonempty) (g : β → α) : (image f s).inf' hs g = s.inf' ⋯ (g ∘ f)

To rewrite from right to left, use Finset.inf'_comp_eq_image.

theorem Finset.sup'_comp_eq_image {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] [DecidableEq β] {s : Finset γ} {f : γ → β} (hs : s.Nonempty) (g : β → α) : s.sup' hs (g ∘ f) = (image f s).sup' ⋯ g

A version of Finset.sup'_image with LHS and RHS reversed. Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.

theorem Finset.inf'_comp_eq_image {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] [DecidableEq β] {s : Finset γ} {f : γ → β} (hs : s.Nonempty) (g : β → α) : s.inf' hs (g ∘ f) = (image f s).inf' ⋯ g

A version of Finset.inf'_image with LHS and RHS reversed. Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.

@[simp]

theorem Finset.sup'_map {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] {s : Finset γ} {f : γ ↪ β} (g : β → α) (hs : (map f s).Nonempty) : (map f s).sup' hs g = s.sup' ⋯ (g ∘ ⇑f)

To rewrite from right to left, use Finset.sup'_comp_eq_map.

@[simp]

theorem Finset.inf'_map {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] {s : Finset γ} {f : γ ↪ β} (g : β → α) (hs : (map f s).Nonempty) : (map f s).inf' hs g = s.inf' ⋯ (g ∘ ⇑f)

To rewrite from right to left, use Finset.inf'_comp_eq_map.

theorem Finset.sup'_comp_eq_map {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeSup α] {s : Finset γ} {f : γ ↪ β} (g : β → α) (hs : s.Nonempty) : s.sup' hs (g ∘ ⇑f) = (map f s).sup' ⋯ g

A version of Finset.sup'_map with LHS and RHS reversed. Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.

theorem Finset.inf'_comp_eq_map {α : Type u_2} {β : Type u_3} {γ : Type u_4} [SemilatticeInf α] {s : Finset γ} {f : γ ↪ β} (g : β → α) (hs : s.Nonempty) : s.inf' hs (g ∘ ⇑f) = (map f s).inf' ⋯ g

A version of Finset.inf'_map with LHS and RHS reversed. Also, this lemma assumes that s is nonempty instead of assuming that its image is nonempty.

theorem Finset.sup'_mono {α : Type u_2} {β : Type u_3} [SemilatticeSup α] (f : β → α) {s₁ s₂ : Finset β} (h : s₁ ⊆ s₂) (h₁ : s₁.Nonempty) : s₁.sup' h₁ f ≤ s₂.sup' ⋯ f

theorem Finset.inf'_mono {α : Type u_2} {β : Type u_3} [SemilatticeInf α] (f : β → α) {s₁ s₂ : Finset β} (h : s₁ ⊆ s₂) (h₁ : s₁.Nonempty) : s₂.inf' ⋯ f ≤ s₁.inf' h₁ f

theorem Finset.sup'_mono_fun {α : Type u_2} {β : Type u_3} [SemilatticeSup α] {s : Finset β} {hs : s.Nonempty} {f g : β → α} (h : ∀ b ∈ s, f b ≤ g b) : s.sup' hs f ≤ s.sup' hs g

theorem Finset.inf'_mono_fun {α : Type u_2} {β : Type u_3} [SemilatticeInf α] {s : Finset β} {hs : s.Nonempty} {f g : β → α} (h : ∀ b ∈ s, g b ≤ f b) : s.inf' hs g ≤ s.inf' hs f

theorem Finset.sup'_eq_sup {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} (H : s.Nonempty) (f : β → α) : s.sup' H f = s.sup f

theorem Finset.inf'_eq_inf {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} (H : s.Nonempty) (f : β → α) : s.inf' H f = s.inf f

@[simp]

theorem Finset.sup'_eq_one {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} [One α] [IsBotOneClass α] (hs : s.Nonempty) : s.sup' hs f = 1 ↔ ∀ i ∈ s, f i = 1

@[simp]

theorem Finset.sup'_eq_zero {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} {f : β → α} [Zero α] [IsBotZeroClass α] (hs : s.Nonempty) : s.sup' hs f = 0 ↔ ∀ i ∈ s, f i = 0

theorem Finset.coe_sup_of_nonempty {α : Type u_2} {β : Type u_3} [SemilatticeSup α] [OrderBot α] {s : Finset β} (h : s.Nonempty) (f : β → α) : ↑(s.sup f) = s.sup (WithBot.some ∘ f)

theorem Finset.coe_inf_of_nonempty {α : Type u_2} {β : Type u_3} [SemilatticeInf α] [OrderTop α] {s : Finset β} (h : s.Nonempty) (f : β → α) : ↑(s.inf f) = s.inf (WithTop.some ∘ f)

@[simp]

theorem Finset.sup_apply {α : Type u_2} {β : Type u_3} {C : β → Type u_7} [(b : β) → SemilatticeSup (C b)] [(b : β) → OrderBot (C b)] (s : Finset α) (f : α → (b : β) → C b) (b : β) : s.sup f b = s.sup fun (a : α) => f a b

@[simp]

theorem Finset.inf_apply {α : Type u_2} {β : Type u_3} {C : β → Type u_7} [(b : β) → SemilatticeInf (C b)] [(b : β) → OrderTop (C b)] (s : Finset α) (f : α → (b : β) → C b) (b : β) : s.inf f b = s.inf fun (a : α) => f a b

@[simp]

theorem Finset.sup'_apply {α : Type u_2} {β : Type u_3} {C : β → Type u_7} [(b : β) → SemilatticeSup (C b)] {s : Finset α} (H : s.Nonempty) (f : α → (b : β) → C b) (b : β) : s.sup' H f b = s.sup' H fun (a : α) => f a b

@[simp]

theorem Finset.inf'_apply {α : Type u_2} {β : Type u_3} {C : β → Type u_7} [(b : β) → SemilatticeInf (C b)] {s : Finset α} (H : s.Nonempty) (f : α → (b : β) → C b) (b : β) : s.inf' H f b = s.inf' H fun (a : α) => f a b

@[simp]

theorem Finset.toDual_sup' {α : Type u_2} {ι : Type u_5} [SemilatticeSup α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) : OrderDual.toDual (s.sup' hs f) = s.inf' hs (⇑OrderDual.toDual ∘ f)

@[simp]

theorem Finset.toDual_inf' {α : Type u_2} {ι : Type u_5} [SemilatticeInf α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) : OrderDual.toDual (s.inf' hs f) = s.sup' hs (⇑OrderDual.toDual ∘ f)

@[simp]

theorem Finset.ofDual_sup' {α : Type u_2} {ι : Type u_5} [SemilatticeInf α] {s : Finset ι} (hs : s.Nonempty) (f : ι → αᵒᵈ) : OrderDual.ofDual (s.sup' hs f) = s.inf' hs (⇑OrderDual.ofDual ∘ f)

@[simp]

theorem Finset.ofDual_inf' {α : Type u_2} {ι : Type u_5} [SemilatticeSup α] {s : Finset ι} (hs : s.Nonempty) (f : ι → αᵒᵈ) : OrderDual.ofDual (s.inf' hs f) = s.sup' hs (⇑OrderDual.ofDual ∘ f)

theorem Finset.sup'_inf_distrib_left {α : Type u_2} {ι : Type u_5} [DistribLattice α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : a ⊓ s.sup' hs f = s.sup' hs fun (i : ι) => a ⊓ f i

theorem Finset.inf'_sup_distrib_left {α : Type u_2} {ι : Type u_5} [DistribLattice α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : a ⊔ s.inf' hs f = s.inf' hs fun (i : ι) => a ⊔ f i

theorem Finset.sup'_inf_distrib_right {α : Type u_2} {ι : Type u_5} [DistribLattice α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : s.sup' hs f ⊓ a = s.sup' hs fun (i : ι) => f i ⊓ a

theorem Finset.inf'_sup_distrib_right {α : Type u_2} {ι : Type u_5} [DistribLattice α] {s : Finset ι} (hs : s.Nonempty) (f : ι → α) (a : α) : s.inf' hs f ⊔ a = s.inf' hs fun (i : ι) => f i ⊔ a

theorem Finset.apply_sup_eq_sup_comp_of_nonempty {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] {s : Finset ι} {f : ι → α} [OrderBot α] [SemilatticeSup β] [OrderBot β] {g : α → β} (mono_g : Monotone g) (H : s.Nonempty) : g (s.sup f) = s.sup (g ∘ f)

theorem Finset.apply_inf_eq_inf_comp_of_nonempty {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] {s : Finset ι} {f : ι → α} [OrderTop α] [SemilatticeInf β] [OrderTop β] {g : α → β} (mono_g : Monotone g) (H : s.Nonempty) : g (s.inf f) = s.inf (g ∘ f)

@[deprecated Finset.apply_sup_eq_sup_comp_of_nonempty (since := "2026-03-25")]

theorem Finset.comp_sup_eq_sup_comp_of_nonempty {α : Type u_2} {β : Type u_3} {ι : Type u_5} [LinearOrder α] {s : Finset ι} {f : ι → α} [OrderBot α] [SemilatticeSup β] [OrderBot β] {g : α → β} (mono_g : Monotone g) (H : s.Nonempty) : g (s.sup f) = s.sup (g ∘ f)

Alias of Finset.apply_sup_eq_sup_comp_of_nonempty.

@[simp]

theorem Finset.le_sup'_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) {f : ι → α} {a : α} : a ≤ s.sup' H f ↔ ∃ b ∈ s, a ≤ f b

@[simp]

theorem Finset.inf'_le_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) {f : ι → α} {a : α} : s.inf' H f ≤ a ↔ ∃ b ∈ s, f b ≤ a

@[simp]

theorem Finset.lt_sup'_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) {f : ι → α} {a : α} : a < s.sup' H f ↔ ∃ b ∈ s, a < f b

@[simp]

theorem Finset.inf'_lt_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) {f : ι → α} {a : α} : s.inf' H f < a ↔ ∃ b ∈ s, f b < a

@[simp]

theorem Finset.sup'_lt_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) {f : ι → α} {a : α} : s.sup' H f < a ↔ ∀ i ∈ s, f i < a

@[simp]

theorem Finset.lt_inf'_iff {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) {f : ι → α} {a : α} : a < s.inf' H f ↔ ∀ i ∈ s, a < f i

theorem Finset.exists_mem_eq_sup' {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) (f : ι → α) : ∃ i ∈ s, s.sup' H f = f i

theorem Finset.exists_mem_eq_inf' {α : Type u_2} {ι : Type u_5} [LinearOrder α] {s : Finset ι} (H : s.Nonempty) (f : ι → α) : ∃ i ∈ s, s.inf' H f = f i

theorem Finset.exists_mem_eq_sup {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderBot α] (s : Finset ι) (h : s.Nonempty) (f : ι → α) : ∃ i ∈ s, s.sup f = f i

theorem Finset.exists_mem_eq_inf {α : Type u_2} {ι : Type u_5} [LinearOrder α] [OrderTop α] (s : Finset ι) (h : s.Nonempty) (f : ι → α) : ∃ i ∈ s, s.inf f = f i

theorem Multiset.map_finset_sup {α : Type u_2} {β : Type u_3} {γ : Type u_4} [DecidableEq α] [DecidableEq β] (s : Finset γ) (f : γ → Multiset β) (g : β → α) (hg : Function.Injective g) : map g (s.sup f) = s.sup (map g ∘ f)

theorem Multiset.count_finset_sup {α : Type u_2} {β : Type u_3} [DecidableEq β] (s : Finset α) (f : α → Multiset β) (b : β) : count b (s.sup f) = s.sup fun (a : α) => count b (f a)

theorem Multiset.mem_sup {α : Type u_7} {β : Type u_8} [DecidableEq β] {s : Finset α} {f : α → Multiset β} {x : β} : x ∈ s.sup f ↔ ∃ v ∈ s, x ∈ f v

@[simp]

theorem Finset.mem_sup' {α : Type u_2} {ι : Type u_5} [DecidableEq α] {s : Finset ι} {f : ι → Finset α} {a : α} (hs : s.Nonempty) : a ∈ s.sup' hs f ↔ ∃ i ∈ s, a ∈ f i

@[simp]

theorem Finset.mem_inf' {α : Type u_2} {ι : Type u_5} [DecidableEq α] {s : Finset ι} {f : ι → Finset α} {a : α} (hs : s.Nonempty) : a ∈ s.inf' hs f ↔ ∀ i ∈ s, a ∈ f i

@[simp]

theorem Finset.mem_sup {α : Type u_2} {ι : Type u_5} [DecidableEq α] {s : Finset ι} {f : ι → Finset α} {a : α} : a ∈ s.sup f ↔ ∃ i ∈ s, a ∈ f i

@[simp]

theorem Finset.sup_singleton_apply {α : Type u_2} {β : Type u_3} [DecidableEq α] (s : Finset β) (f : β → α) : (s.sup fun (b : β) => {f b}) = image f s

@[simp]

theorem Finset.sup_singleton_eq_self {α : Type u_2} [DecidableEq α] (s : Finset α) : s.sup singleton = s