Documentation

Mathlib.Order.SuccPred.CompleteLinearOrder

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

theorem csSup_mem_of_not_isSuccLimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} (hne : s.Nonempty) (hbdd : BddAbove s) (hlim : ¬Order.IsSuccLimit (sSup s)) :
sSup s ∈ s
theorem csInf_mem_of_not_isPredLimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} (hne : s.Nonempty) (hbdd : BddBelow s) (hcolim : ¬Order.IsPredLimit (sInf s)) :
sInf s ∈ s
theorem exists_eq_ciSup_of_not_isSuccLimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} (hbdd : BddAbove (Set.range f)) (hf : ¬Order.IsSuccLimit (⨆ (i : ι), f i)) :
∃ (i : ι), f i = ⨆ (i : ι), f i
theorem exists_eq_ciInf_of_not_isPredLimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} (hbdd : BddBelow (Set.range f)) (hf : ¬Order.IsPredLimit (⨅ (i : ι), f i)) :
∃ (i : ι), f i = ⨅ (i : ι), f i
@[deprecated csInf_mem_of_not_isPredLimit (since := "2026-04-24")]
theorem csInf_mem_of_not_isPredPrelimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} (hne : s.Nonempty) (hbdd : BddBelow s) (hlim : ¬Order.IsPredPrelimit (sInf s)) :
sInf s ∈ s
@[deprecated exists_eq_ciInf_of_not_isPredLimit (since := "2026-04-24")]
theorem exists_eq_ciInf_of_not_isPredPrelimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} (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_isSuccLimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} {x : α} (hs : IsLUB s x) (hne : s.Nonempty) (hx : ¬Order.IsSuccLimit x) :
x ∈ s
theorem IsGLB.mem_of_nonempty_of_not_isPredLimit {α : Type u_2} [ConditionallyCompleteLinearOrder α] {s : Set α} {x : α} (hs : IsGLB s x) (hne : s.Nonempty) (hx : ¬Order.IsPredLimit x) :
x ∈ s
theorem IsLUB.exists_of_nonempty_of_not_isSuccLimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} {x : α} (hf : IsLUB (Set.range f) x) (hx : ¬Order.IsSuccLimit x) :
∃ (i : ι), f i = x
theorem IsGLB.exists_of_nonempty_of_not_isPredLimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} {x : α} (hf : IsGLB (Set.range f) x) (hx : ¬Order.IsPredLimit x) :
∃ (i : ι), f i = x
@[deprecated IsLUB.mem_of_nonempty_of_not_isSuccLimit (since := "2026-04-24")]
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
@[deprecated IsGLB.mem_of_nonempty_of_not_isPredLimit (since := "2026-04-24")]
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
@[deprecated IsLUB.exists_of_nonempty_of_not_isSuccLimit (since := "2026-04-24")]
theorem IsLUB.exists_of_nonempty_of_not_isSuccPrelimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} {x : α} (hf : IsLUB (Set.range f) x) (hx : ¬Order.IsSuccPrelimit x) :
∃ (i : ι), f i = x
@[deprecated IsGLB.exists_of_nonempty_of_not_isPredLimit (since := "2026-04-24")]
theorem IsGLB.exists_of_nonempty_of_not_isPredPrelimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrder α] [Nonempty ι] {f : ι → α} {x : α} (hf : IsGLB (Set.range f) x) (hx : ¬Order.IsPredPrelimit x) :
∃ (i : ι), f i = x
@[instance_reducible, deprecated SuccOrder.ofLinearWellFoundedLT (since := "2026-04-12")]

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
    @[deprecated csSup_mem_of_not_isSuccPrelimit (since := "2026-04-24")]

    Alias of csSup_mem_of_not_isSuccPrelimit.


    See csSup_mem_of_not_isSuccLimit for the ConditionallyCompleteLinearOrder version.

    theorem exists_eq_ciSup_of_not_isSuccPrelimit {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] {f : ι → α} (hf' : ¬Order.IsSuccPrelimit (⨆ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨆ (i : ι), f i

    See exists_eq_ciSup_of_not_isSuccLimit for the ConditionallyCompleteLinearOrder version.

    @[deprecated exists_eq_ciSup_of_not_isSuccPrelimit (since := "2026-04-24")]
    theorem exists_eq_ciSup_of_not_isSuccPrelimit' {ι : Sort u_1} {α : Type u_2} [ConditionallyCompleteLinearOrderBot α] {f : ι → α} (hf' : ¬Order.IsSuccPrelimit (⨆ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨆ (i : ι), f i

    Alias of exists_eq_ciSup_of_not_isSuccPrelimit.


    See exists_eq_ciSup_of_not_isSuccLimit for the ConditionallyCompleteLinearOrder version.

    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 : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} (hf : ¬Order.IsSuccPrelimit (⨆ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨆ (i : ι), f i
    theorem exists_eq_iInf_of_not_isPredPrelimit {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} (hf : ¬Order.IsPredPrelimit (⨅ (i : ι), f i)) :
    ∃ (i : ι), f i = ⨅ (i : ι), f i
    theorem sSup_lt_iff_of_not_isSuccPrelimit {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : ¬Order.IsSuccPrelimit x) :
    sSup s < x ↔ ∀ a ∈ s, a < x

    Similar to sSup_lt_iff but with a weaker RHS, as it does not require a uniform bound.

    theorem lt_sInf_iff_of_not_isPredPrelimit {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : ¬Order.IsPredPrelimit x) :
    x < sInf s ↔ ∀ a ∈ s, x < a

    Similar to lt_sInf_iff but with a weaker RHS, as it does not require a uniform bound.

    theorem iSup_lt_iff_of_not_isSuccPrelimit {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : ¬Order.IsSuccPrelimit x) :
    ⨆ (i : ι), f i < x ↔ ∀ (i : ι), f i < x

    Similar to iSup_lt_iff but with a weaker RHS, as it does not require a uniform bound.

    theorem lt_iInf_iff_of_not_isPredPrelimit {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : ¬Order.IsPredPrelimit x) :
    x < ⨅ (i : ι), f i ↔ ∀ (i : ι), x < f i

    Similar to lt_iInf_iff but with a weaker RHS, as it does not require a uniform bound.

    theorem le_sSup_iff_of_not_isSuccPrelimit {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : ¬Order.IsSuccPrelimit x) :
    x ≤ sSup s ↔ ∃ a ∈ s, x ≤ a

    Similar to le_sSup_iff_forall_lt but with a stronger RHS, as it requires a uniform bound.

    theorem sInf_le_iff_of_not_isPredPrelimit {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : ¬Order.IsPredPrelimit x) :
    sInf s ≤ x ↔ ∃ a ∈ s, a ≤ x

    Similar to sInf_le_iff_forall_lt but with a stronger RHS, as it requires a uniform bound.

    theorem le_iSup_iff_of_not_isSuccPrelimit {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : ¬Order.IsSuccPrelimit x) :
    x ≤ ⨆ (i : ι), f i ↔ ∃ (i : ι), x ≤ f i

    Similar to le_iSup_iff_forall_lt but with a stronger RHS, as it requires a uniform bound.

    theorem iInf_le_iff_of_not_isPredPrelimit {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : ¬Order.IsPredPrelimit x) :
    ⨅ (i : ι), f i ≤ x ↔ ∃ (i : ι), f i ≤ x

    Similar to iInf_le_iff_forall_lt but with a stronger RHS, as it requires a uniform bound.

    theorem Order.IsSuccPrelimit.sSup_lt_iff {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : IsSuccPrelimit x) :
    sSup s < x ↔ ∃ a < x, ∀ b ∈ s, b < a

    Similar to sSup_lt_iff but with a stronger RHS, as it requires a strict inequality.

    theorem Order.IsPredPrelimit.lt_sInf_iff {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : IsPredPrelimit x) :
    x < sInf s ↔ ∃ (a : α), x < a ∧ ∀ b ∈ s, a < b

    Similar to lt_sInf_iff but with a stronger RHS, as it requires a strict inequality.

    theorem Order.IsSuccPrelimit.iSup_lt_iff {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : IsSuccPrelimit x) :
    ⨆ (i : ι), f i < x ↔ ∃ a < x, ∀ (i : ι), f i < a

    Similar to iSup_lt_iff but with a stronger RHS, as it requires a strict inequality.

    theorem Order.IsPredPrelimit.lt_iInf_iff {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : IsPredPrelimit x) :
    x < ⨅ (i : ι), f i ↔ ∃ (a : α), x < a ∧ ∀ (i : ι), a < f i

    Similar to lt_iInf_iff but with a stronger RHS, as it requires a strict inequality.

    theorem Order.IsSuccPrelimit.le_sSup_iff {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : IsSuccPrelimit x) :

    Similar to le_sSup_iff_forall_lt but with a weaker RHS, as it requires a non-strict inequality.

    theorem Order.IsPredPrelimit.sInf_le_iff {α : Type u_2} [CompleteLinearOrder α] {s : Set α} {x : α} (h : IsPredPrelimit x) :

    Similar to sInf_le_iff_forall_lt but with a weaker RHS, as it requires a non-strict inequality.

    theorem Order.IsSuccPrelimit.le_iSup_iff {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : IsSuccPrelimit x) :
    x ≤ ⨆ (i : ι), f i ↔ ∀ a < x, ∃ (i : ι), a ≤ f i

    Similar to le_iSup_iff_forall_lt but with a weaker RHS, as it requires a non-strict inequality.

    theorem Order.IsPredPrelimit.iInf_le_iff {ι : Sort u_1} {α : Type u_2} [CompleteLinearOrder α] {f : ι → α} {x : α} (h : IsPredPrelimit x) :
    ⨅ (i : ι), f i ≤ x ↔ ∀ (a : α), x < a → ∃ (i : ι), f i ≤ a

    Similar to iInf_le_iff_forall_lt but with a weaker RHS, as it requires a non-strict inequality.