No portion of work contained in this thesis has been submitted in support of any application for any other degree or qualification of this or any other university or institute of learning.
Much of chapter three is based on previously published work by M. Unwalla and J. Kerridge for BNCOD10 - the work presented here was written by M. Unwalla.
Chapter four closely follows a joint paper submitted for publication by M. Unwalla and J. Kerridge, all the material used being the sole work of the first named author.