New Upper Bounds for Nonbinary Codes Based on the Terwilliger Algebra and Semidefinite Programming

Authors
Publication date 2006
Journal Journal of Combinatorial Theory. Series A
Volume | Issue number 113 | 8
Pages (from-to) 1719-1731
Organisations
  • Faculty of Science (FNWI) - Korteweg-de Vries Institute for Mathematics (KdVI)
Abstract Abstract:
We give a new upper bound on the maximum size $A_q(n,d)$ of a code of word
length $n$ and minimum Hamming distance at least $d$ over the alphabet of
$q\geq 3$ letters. By block-diagonalizing the Terwilliger algebra of the
nonbinary Hamming scheme, the bound can be calculated in time polynomial
in $n$ using semidefinite programming. For $q=3,4,5$ this gives several
improved upper bounds for concrete values of $n$ and $d$. This work is
related to \cite{Lex}, where a similar approach is used to derive upper
bounds for binary codes.
Document type Article
Published at https://doi.org/10.1016/j.jcta.2006.03.010
Published at http://www.sciencedirect.com/science/journal/00973165
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