Corollary int_op_value_of_hist : forall h, Forall int_op (map snd h) -> tc_val tint (value_of_hist h).

Lemma make_map_drop : forall h1 h2 (Hz : Forall (fun x => value_of_hist (fst x) = vint 0) h2), make_map (h1 ++ h2) = make_map h1.