(* module Ptset = 
struct 
  include Set.Make (struct type t = int let compare = (-) end)
  let hash = Hashtbl.hash
end
  *)
include FiniteCofinite.Make(Ptset)

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