rewrite Share.lub_commute in H'.
rewrite Share.lub_bot in H'.
auto.
Qed.

(* Specifications: *)
Lemma join_top_r sh1 sh3 : join sh1 Share.top sh3 -> sh1 = Share.bot.
Lemma join_pshare_top_l (p1 p2 p3 : pshare) :
@join pshare _ p1 p2 p3 ->
pshare_sh p1 <> Share.top.
Lemma join_pshare_top_r (p1 p2 p3 : pshare) :
@join pshare _ p1 p2 p3 ->
pshare_sh p2 <> Share.top.