Subuniverse. Proof. rapply (Build_Subuniverse (IsConnected O)). simpl; intros T U isconnT f isequivf. exact (isconnected_equiv T f isconnT). Defined.
Require Import HoTT.Basics HoTT.Types. Require Import Equiv.BiInv Extensions HProp HFiber NullHomotopy Limits.Pullback. Require Import Homotopy.IdentitySystems. Require Import Colimits.Pushout.