Suspensions of pointed types

Content created by Fredrik Bakke, Egbert Rijke and Raymond Baker.

Created on 2023-08-28.
Last modified on 2024-04-11.

module synthetic-homotopy-theory.suspensions-of-pointed-types where
open import foundation.constant-maps
open import foundation.dependent-pair-types
open import foundation.identity-types
open import foundation.universe-levels

open import structured-types.pointed-types

open import synthetic-homotopy-theory.loop-spaces
open import synthetic-homotopy-theory.suspension-structures
open import synthetic-homotopy-theory.suspensions-of-types


When X is a pointed type, the suspension of X has nice properties

The suspension of a pointed type

suspension-Pointed-Type :
  {l : Level}  Pointed-Type l  Pointed-Type l
pr1 (suspension-Pointed-Type X) = suspension (type-Pointed-Type X)
pr2 (suspension-Pointed-Type X) = north-suspension

Suspension structure induced by a pointed type

constant-suspension-structure-Pointed-Type :
  {l1 l2 : Level} (X : UU l1) (Y : Pointed-Type l2) 
  suspension-structure X (type-Pointed-Type Y)
pr1 (constant-suspension-structure-Pointed-Type X Y) =
  point-Pointed-Type Y
pr1 (pr2 (constant-suspension-structure-Pointed-Type X Y)) =
  point-Pointed-Type Y
pr2 (pr2 (constant-suspension-structure-Pointed-Type X Y)) =
  const X refl

Suspension structure induced by a map into a loop space

The following function takes a map X → Ω Y and returns a suspension structure on Y.

module _
  {l1 l2 : Level} (X : UU l1) (Y : Pointed-Type l2)
  suspension-structure-map-into-Ω :
    (X  type-Ω Y)  suspension-structure X (type-Pointed-Type Y)
  pr1 (suspension-structure-map-into-Ω f) = point-Pointed-Type Y
  pr1 (pr2 (suspension-structure-map-into-Ω f)) = point-Pointed-Type Y
  pr2 (pr2 (suspension-structure-map-into-Ω f)) = f

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