Require Import HoTT.Basics HoTT.Types.
Require Import Modality Accessible.
Local Open Scope path_scope.
(** * The identity modality *) (** Everything to say here is fairly trivial. *)
Definition purely : Modality.
Proof.
srapply (Build_Modality (fun _ => Unit) _ _ idmap).
1-2,6:intros; exact tt.
-
intros; assumption.
-
intros ? ? ? f z; exact (f z).
-
intros; reflexivity.
Defined.
Instance accmodality_purely : IsAccModality purely.
Proof.
unshelve econstructor.
-
econstructor.
exact (@Empty_rec Type).
-
intros X; split.
+
intros _ [].
+
intros; exact tt.
Defined.