Axiom ghost_precise : forall sh {t} p, precise (EX f : share * hist (reptype t), ghost sh f p).

Lemma list_incl_app : forall {A} (l1 l2 l1' l2' : list A), list_incl l1 l2 -> list_incl l1' l2' -> list_incl (l1 ++ l1') (l2 ++ l2').