Documentation

Mathlib.Order.SuccPred.CompleteLinearOrder

Relation between IsSuccPrelimit and iSup in (conditionally) complete linear orders. #

theorem exists_eq_ciSup_of_not_isSuccPrelimit {ι : Type u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ια} (hf : BddAbove (Set.range f)) (hf' : ¬Order.IsSuccPrelimit (⨆ (i : ι), f i)) :
∃ (i : ι), f i = ⨆ (i : ι), f i
theorem exists_eq_ciInf_of_not_isPredPrelimit {ι : Type u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ια} (hf : BddBelow (Set.range f)) (hf' : ¬Order.IsPredPrelimit (⨅ (i : ι), f i)) :
∃ (i : ι), f i = ⨅ (i : ι), f i
theorem IsLUB.mem_of_nonempty_of_not_isSuccPrelimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} {x : α} (hs : IsLUB s x) (hne : s.Nonempty) (hx : ¬Order.IsSuccPrelimit x) :
x s
theorem IsGLB.mem_of_nonempty_of_not_isPredPrelimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} {x : α} (hs : IsGLB s x) (hne : s.Nonempty) (hx : ¬Order.IsPredPrelimit x) :
x s
theorem IsLUB.exists_of_nonempty_of_not_isSuccPrelimit {ι : Type u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ια} {x : α} (hf : IsLUB (Set.range f) x) (hx : ¬Order.IsSuccPrelimit x) :
∃ (i : ι), f i = x
theorem IsGLB.exists_of_nonempty_of_not_isPredPrelimit {ι : Type u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ια} {x : α} (hf : IsGLB (Set.range f) x) (hx : ¬Order.IsPredPrelimit x) :
∃ (i : ι), f i = x

Every conditionally complete linear order with well-founded < is a successor order, by setting the successor of an element to be the infimum of all larger elements.

Equations
Instances For
    theorem exists_eq_ciSup_of_not_isSuccPrelimit' {ι : Type u_1} {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] {f : ια} (hf : BddAbove (Set.range f)) (hf' : ¬Order.IsSuccPrelimit (⨆ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨆ (i : ι), f i

    See exists_eq_ciSup_of_not_isSuccPrelimit for the ConditionallyCompleteLinearOrder version.

    @[deprecated IsLUB.mem_of_not_isSuccPrelimit (since := "2025-01-05")]
    theorem IsLUB.exists_of_not_isSuccPrelimit {ι : Type u_1} {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] {f : ια} {x : α} (hf : IsLUB (Set.range f) x) (hx : ¬Order.IsSuccPrelimit x) :
    ∃ (i : ι), f i = x
    theorem Order.IsSuccPrelimit.iSup_Iio {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] {x : α} (h : IsSuccPrelimit x) :
    ⨆ (a : (Set.Iio x)), a = x
    theorem Order.IsSuccLimit.iSup_Iio {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] {x : α} (h : IsSuccLimit x) :
    ⨆ (a : (Set.Iio x)), a = x
    theorem iSup_succ {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] [SuccOrder α] (x : α) :
    ⨆ (a : (Set.Iio x)), Order.succ a = x
    theorem exists_eq_iSup_of_not_isSuccPrelimit {ι : Type u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ια} (hf : ¬Order.IsSuccPrelimit (⨆ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨆ (i : ι), f i
    theorem exists_eq_iInf_of_not_isPredPrelimit {ι : Type u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ια} (hf : ¬Order.IsPredPrelimit (⨅ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨅ (i : ι), f i
    @[deprecated IsGLB.mem_of_not_isPredLimit (since := "2025-01-05")]
    theorem IsGLB.exists_of_not_isPredPrelimit {ι : Type u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ια} {x : α} (hf : IsGLB (Set.range f) x) (hx : ¬Order.IsPredPrelimit x) :
    ∃ (i : ι), f i = x