(** Infinitely many non-silent transitions *)
CoInductive forever_reactive : state -> traceinf -> Prop :=
| forever_reactive_intro: forall s1 s2 t T,
star s1 t s2 -> t <> E0 -> forever_reactive s2 T ->
forever_reactive s1 (t *** T).

(* Specifications: *)
Lemma star_forever_reactive:
forall s1 t s2 T,
star s1 t s2 -> forever_reactive s2 T ->
forever_reactive s1 (t *** T).