Section Timeless.
Definition except0 P := P || |>FF.
Definition timeless P := |>P |-- except0 P.
Definition timeless' (P : mpred) := forall (a a' : rmap),
predicates_hered.app_pred P a' -> age a a' ->
predicates_hered.app_pred P a.

Lemma own_timeless : forall {P : Ghost} g (a : G), timeless (own g a NoneP).