An Improved Bound on the List Size in the Guruswami-sudan Algorithm for Ag Codes

Given an algebraic geometry code CL(D,αP ), the GuruswamiSudan algorithm produces a list of all codewords in CL(D,αP ) within a specified distance of a received word. The initialization step in the algorithm involves parameter choices that bound the degree of the interpolating polynomial and hence the length of the list of codewords generated. In this paper, we use simple properties of discriminants of polynomials over finite fields to provide improved parameter choices for the Guruswami-Sudan list decoding algorithm for algebraic geometry codes. As a consequence, we obtain obtain a better bound on the list size.