(X : Type) `{In Meet X} : IsEquiv (to_plus X). Proof. apply (@isequiv_compose _ _ (to O X) _ _ (to L (O X))). apply isequiv_to_O_inO. apply (inO_equiv_inO X (to O X)). Defined.
Require Import HoTT.Basics HoTT.Types. Require Import Extensions HFiber Truncations NullHomotopy Limits.Pullback. Require Import Descent Lex Separated.