Large suplattices

Content created by Egbert Rijke, Fredrik Bakke, Jonathan Prieto-Cubides, Julian KG, Maša Žaucer, Victor Blanchi, fernabnor and louismntnu.

Created on 2023-05-09.
Last modified on 2023-09-21.

module order-theory.large-suplattices where


open import foundation.dependent-pair-types
open import foundation.large-binary-relations
open import foundation.binary-relations
open import foundation.identity-types
open import foundation.logical-equivalences
open import foundation.propositions
open import foundation.sets
open import foundation.universe-levels

open import order-theory.large-posets
open import order-theory.posets
open import order-theory.suplattices
open import order-theory.least-upper-bounds-large-posets
open import order-theory.upper-bounds-large-posets


A large suplattice is a large poset P such that for every family

  x : I → type-Large-Poset P l1

indexed by I : UU l2 there is an element ⋁ x : type-Large-Poset P (l1 ⊔ l2) such that the logical equivalence

  (∀ᵢ xᵢ ≤ y) ↔ ((⋁ x) ≤ y)

holds for every element y : type-Large-Poset P l3.


The predicate on large posets of having least upper bounds of families of elements

module _
  {α : Level  Level} {β : Level  Level  Level} (γ : Level)
  (P : Large-Poset α β)

  is-large-suplattice-Large-Poset : UUω
  is-large-suplattice-Large-Poset =
    {l1 l2 : Level} {I : UU l1} (x : I  type-Large-Poset P l2) 
    has-least-upper-bound-family-of-elements-Large-Poset γ P x

  module _
    (H : is-large-suplattice-Large-Poset)
    {l1 l2 : Level} {I : UU l1} (x : I  type-Large-Poset P l2)

    sup-is-large-suplattice-Large-Poset : type-Large-Poset P (γ  l1  l2)
    sup-is-large-suplattice-Large-Poset =
      sup-has-least-upper-bound-family-of-elements-Large-Poset (H x)

    is-least-upper-bound-sup-is-large-suplattice-Large-Poset :
      is-least-upper-bound-family-of-elements-Large-Poset P x
    is-least-upper-bound-sup-is-large-suplattice-Large-Poset =
        ( H x)

Large suplattices

    (α : Level  Level) (β : Level  Level  Level) (γ : Level) : UUω
    large-poset-Large-Suplattice : Large-Poset α β
    is-large-suplattice-Large-Suplattice :
      is-large-suplattice-Large-Poset γ large-poset-Large-Suplattice

open Large-Suplattice public

module _
  {α : Level  Level} {β : Level  Level  Level} {γ : Level}
  (L : Large-Suplattice α β γ)

  set-Large-Suplattice : (l : Level)  Set (α l)
  set-Large-Suplattice = set-Large-Poset (large-poset-Large-Suplattice L)

  type-Large-Suplattice : (l : Level)  UU (α l)
  type-Large-Suplattice = type-Large-Poset (large-poset-Large-Suplattice L)

  is-set-type-Large-Suplattice : {l : Level}  is-set (type-Large-Suplattice l)
  is-set-type-Large-Suplattice =
    is-set-type-Large-Poset (large-poset-Large-Suplattice L)

  leq-prop-Large-Suplattice :
    Large-Relation-Prop α β type-Large-Suplattice
  leq-prop-Large-Suplattice =
    leq-prop-Large-Poset (large-poset-Large-Suplattice L)

  leq-Large-Suplattice :
    Large-Relation α β type-Large-Suplattice
  leq-Large-Suplattice = leq-Large-Poset (large-poset-Large-Suplattice L)

  is-prop-leq-Large-Suplattice :
    is-prop-Large-Relation type-Large-Suplattice leq-Large-Suplattice
  is-prop-leq-Large-Suplattice =
    is-prop-leq-Large-Poset (large-poset-Large-Suplattice L)

  refl-leq-Large-Suplattice :
    is-reflexive-Large-Relation type-Large-Suplattice leq-Large-Suplattice
  refl-leq-Large-Suplattice =
    refl-leq-Large-Poset (large-poset-Large-Suplattice L)

  antisymmetric-leq-Large-Suplattice :
    is-antisymmetric-Large-Relation type-Large-Suplattice leq-Large-Suplattice
  antisymmetric-leq-Large-Suplattice =
    antisymmetric-leq-Large-Poset (large-poset-Large-Suplattice L)

  transitive-leq-Large-Suplattice :
    is-transitive-Large-Relation type-Large-Suplattice leq-Large-Suplattice
  transitive-leq-Large-Suplattice =
    transitive-leq-Large-Poset (large-poset-Large-Suplattice L)

  sup-Large-Suplattice :
    {l1 l2 : Level} {I : UU l1} (x : I  type-Large-Suplattice l2) 
    type-Large-Suplattice (γ  l1  l2)
  sup-Large-Suplattice x =
      ( is-large-suplattice-Large-Suplattice L x)

  is-upper-bound-family-of-elements-Large-Suplattice :
    {l1 l2 l3 : Level} {I : UU l1} (x : I  type-Large-Suplattice l2)
    (y : type-Large-Suplattice l3)  UU (β l2 l3  l1)
  is-upper-bound-family-of-elements-Large-Suplattice x y =
      ( large-poset-Large-Suplattice L)
      ( x)
      ( y)

  is-least-upper-bound-family-of-elements-Large-Suplattice :
    {l1 l2 l3 : Level} {I : UU l1} (x : I  type-Large-Suplattice l2) 
    type-Large-Suplattice l3  UUω
  is-least-upper-bound-family-of-elements-Large-Suplattice =
      ( large-poset-Large-Suplattice L)

  is-least-upper-bound-sup-Large-Suplattice :
    {l1 l2 : Level} {I : UU l1} (x : I  type-Large-Suplattice l2) 
    is-least-upper-bound-family-of-elements-Large-Suplattice x
      ( sup-Large-Suplattice x)
  is-least-upper-bound-sup-Large-Suplattice x =
      ( is-large-suplattice-Large-Suplattice L x)

  is-upper-bound-sup-Large-Suplattice :
    {l1 l2 : Level} {I : UU l1} (x : I  type-Large-Suplattice l2) 
    is-upper-bound-family-of-elements-Large-Suplattice x
      ( sup-Large-Suplattice x)
  is-upper-bound-sup-Large-Suplattice x =
      ( is-least-upper-bound-sup-Large-Suplattice x (sup-Large-Suplattice x))
      ( refl-leq-Large-Suplattice (sup-Large-Suplattice x))


The operation sup is order preserving

module _
  {α : Level  Level} {β : Level  Level  Level} {γ : Level}
  (L : Large-Suplattice α β γ)

  preserves-order-sup-Large-Suplattice :
    {l1 l2 l3 : Level} {I : UU l1}
    {x : I  type-Large-Suplattice L l2}
    {y : I  type-Large-Suplattice L l3} 
    ((i : I)  leq-Large-Suplattice L (x i) (y i)) 
    leq-Large-Suplattice L
      ( sup-Large-Suplattice L x)
      ( sup-Large-Suplattice L y)
  preserves-order-sup-Large-Suplattice {x = x} {y} H =
      ( is-least-upper-bound-sup-Large-Suplattice L x
        ( sup-Large-Suplattice L y))
      ( λ i 
        transitive-leq-Large-Suplattice L
          ( x i)
          ( y i)
          ( sup-Large-Suplattice L y)
          ( is-upper-bound-sup-Large-Suplattice L y i)
          ( H i))

Small suplattices from large suplattices

module _
  {α : Level  Level} {β : Level  Level  Level} {γ : Level}
  (L : Large-Suplattice α β γ)

  poset-Large-Suplattice : (l : Level)  Poset (α l) (β l l)
  poset-Large-Suplattice = poset-Large-Poset (large-poset-Large-Suplattice L)

  is-suplattice-poset-Large-Suplattice :
    (l1 l2 : Level) 
    is-suplattice-Poset l1 (poset-Large-Suplattice (γ  l1  l2))
  pr1 (is-suplattice-poset-Large-Suplattice l1 l2 I f) =
    sup-Large-Suplattice L f
  pr2 (is-suplattice-poset-Large-Suplattice l1 l2 I f) =
    is-least-upper-bound-sup-Large-Suplattice L f

  suplattice-Large-Suplattice :
    (l1 l2 : Level) 
    Suplattice (α (γ  l1  l2)) (β (γ  l1  l2) (γ  l1  l2)) (l1)
  pr1 (suplattice-Large-Suplattice l1 l2) =
    poset-Large-Suplattice (γ  l1  l2)
  pr2 (suplattice-Large-Suplattice l1 l2) =
    is-suplattice-poset-Large-Suplattice l1 l2

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