-let domImpl = Gdome.domImplementation ();;
-let helmns = Gdome.domString "http://www.cs.unibo.it/helm";;
+let domImpl = Gdome.domImplementation ()
+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"