Unique existence

module foundation.unique-existence where

open import foundation-core.contractible-types
open import foundation-core.dependent-pair-types
open import foundation-core.universe-levels

Idea

Unique existence ∃! A B is defined as Σ A B being contractible.

Definition

∃! : {l1 l2 : Level} → (A : UU l1) → (A → UU l2) → UU (l1 ⊔ l2)
∃! A B = is-contr (Σ A B)