(* module Ptset = 
struct 
  include Set.Make (struct type t = int let compare = (-) end)
  let hash = Hashtbl.hash
end
  *)
module M  : FiniteCofinite.S with type elt = Tag.t and type set = Ptset.t =
  FiniteCofinite.Make(Ptset)
include M


let tag t = singleton t
let pcdata = singleton Tag.pcdata
let attribute = singleton Tag.attribute
let star = diff any (cup pcdata attribute)
let node = neg attribute