(* Why isn't this automatic? *)
Instance zero_ord_preorder : RelationClasses.PreOrder zero_ord.Instance table_incl_preorder : RelationClasses.PreOrder table_incl.

Lemma add_fails : forall k v b l H H' (HH : apply_hist H l H') (Hadd : In (HAdd k v b) l) (Hk : H k <> None), b = false.