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

Lemma hashtable_A_join : forall lgk lgv entries, hashtable_A (repeat (0, singleton 0 0) (Z.to_nat size)) lgk lgv entries * hashtable_A (repeat (0, singleton 0 0) (Z.to_nat size)) lgk lgv entries = hashtable_A (repeat (0, singleton 0 0) (Z.to_nat size)) lgk lgv entries.