The trace operator and redundancy of Goppa codes

Abstract

The dimension of subfield subcodes and in particular generalized Goppa codes is studied using the kernel of an associated trace map. Bounds on the dimension for a particular general class of binary Goppa codes are obtained. Deeper study of some special cases and other related polynomials yields still tighter bounds for any s>1.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>