Section simpler_invariant_tentative.
(* This section about getYES and getNO is currently unused.  Maybe it would give us a simpler invariant, but maybe not. *)
(* Variable unrel_lsh_rsh : Share.unrel Share.Lsh Share.Rsh = Share.bot. *)

Lemma mapsto_getYES sh t v v' phi :
writable0_share sh ->
app_pred (mapsto sh t v v') phi ->
app_pred (mapsto Share.Rsh t v v') (getYES phi).