let helm_ns = Gdome.domString "http://www.cs.unibo.it/helm"
let xlink_ns = Gdome.domString "http://www.w3.org/1999/xlink"
let mathml_ns = Gdome.domString "http://www.w3.org/1998/Math/MathML"
+let boxml_ns = Gdome.domString "http://helm.cs.unibo.it/2003/BoxML"
(* TODO BRRRRR .... *)
(** strip first 4 line of a string, used to strip xml declaration and doctype