DDiagram (span f g). Proof. simple refine (Build_Diagram _ _ _); cbn. - intros [[] x]; revert x. + exact A0. + destruct b; assumption. - intros [[[]|[]] x] [[[]|[]] y]; cbn; intros [[] p]. + exact (fun y => p # (f0 x y)). + exact (fun y => p # (g0 x y)). Defined.
Require Import Basics. Require Import Types. Require Import Diagrams.Diagram. Require Import Diagrams.DDiagram. Require Import Diagrams.Span. Require Import Diagrams.Cocone. Require Import Colimits.Colimit. Require Import Colimits.Colimit_Pushout. Require Import Colimits.Colimit_Flattening.