Holger Spakowski Rahul Tripathi LWPP and WPP are not uniformly gap-definable. 660-689 2006 72 J. Comput. Syst. Sci. 4 http://dx.doi.org/10.1016/j.jcss.2006.01.002 db/journals/jcss/jcss72.html#SpakowskiT06