Thanks should go to Jim Davies at the Dept of Computer Science, University of Oxford for editing & releasing this updated version on the web by the way. ( http

Thanks should go to Jim Davies at the Dept of Computer Science, University of Oxford for editing & releasing this updated version on the web by the way. ( http://www.cs.ox.ac.uk/people/jim.davies/ http://www.cs.ox.ac.uk/people/jim.davies/ )