(*  NOT TRUE, because readable doesn't constraint NoneP ... Lemma readable_VAL: forall w l, readable l (w_m w) <-> exists sh, (VALspec sh l * TT) w.  *)

Lemma yesat_join_sub:
forall pp k l sh m m',
join_sub m m' ->
yesat pp k sh l m ->
exists sh', yesat pp k sh' l m'.