proposition: Theorem add_one_eq_succ (d : mynat) : d + 1 = succ d.
proof: Proof. rewrite succ_eq_add_one. reflexivity. Qed.
imports: Unicode.Utf8 Game.Mynat.Definition Game.Mynat.Add Game.World.Addition Game.World.Proposition Game.World.AdvancedProposition Setoid