Set Implicit Arguments.
Definition Tsh : share := Share.top.
Definition nonempty_share (sh: share) :=
sepalg.nonidentity sh.
Definition readable_share (sh: share) :=
nonempty_share (Share.glb Share.Rsh sh).
Definition writable_share (sh: share) :=
nonempty_share (Share.glb Share.Lsh sh) /\ join_sub Share.Rsh sh.
Hint Resolve writable_readable : core.

Lemma glb_Rsh_not_top:
forall sh, Share.glb Share.Rsh sh <> Share.top.