Hint Resolve thread_inv_exclusive.

Lemma ghost_part_share_join : forall g sh1 sh2 sh n1 n2, sh1 <> Share.bot -> sh2 <> Share.bot ->
sepalg.join sh1 sh2 sh ->
ghost_part g sh1 n1 * ghost_part g sh2 n2 = ghost_part g sh (n1 + n2)%nat.