(* Not true for for writable, only for writable0 *)

(* Specifications: *)
Lemma readable_glb:
forall sh,
readable_share sh ->
readable_share (Share.glb Share.Rsh sh).
Lemma unreadable_glb:
forall sh,
~readable_share sh ->
~readable_share (Share.glb Share.Rsh sh).
Lemma nonreadable_emptyshare: ~ readable_share emptyshare.
Lemma join_comp_Tsh:
forall sh, sepalg.join sh (Share.comp sh) Tsh.