Definition kv_stable {X} (m : Poram X) : Prop :=
  forall s, poram_lift (state_equiv s) (state_equiv s) triv m.

(* Specifications: *)
Lemma mreturn_stable {X} (x : X) : kv_stable (mreturn x).
Lemma read_stable k' : kv_stable (read k').
Lemma mreturn_stable {X} (x : X) : kv_stable (mreturn x).
Lemma read_stable k' : kv_stable (read k').