`{Funext} {A B P : Type} `{IsHProp P} (f : A -> P) : (Join A B -> P) <~> (B -> P). Proof. apply equiv_iff_hprop. 1: exact (fun f => f o joinr). intros g. snrapply Join_rec. 1,2: assumption. intros a b. apply path_ishprop. Defined.
Require Import Basics Types. Require Import Cubical.DPath Cubical.PathSquare. Require Import NullHomotopy. Require Import Extensions. Require Import Colimits.Pushout. Require Import Truncations.Core Truncations.Connectedness. Require Import Pointed.Core. Require Import WildCat. Require Import Spaces.Nat.Core.