Definition hist_incl (h : hist_part) l := forall t e, h t = Some e -> nth_error l t = Some e.
Definition hist_list (h : hist_part) l := forall t e, h t = Some e <-> nth_error l t = Some e.

Lemma hist_ref_incl : forall sh h h' p, sh <> Share.bot ->
ghost_hist sh h p * ghost_ref h' p |-- !!hist_incl h h'.