Title
On a Conjecture Regarding Identification in Hamming Graphs
Abstract
In 2013, Goddard and Wash studied identifying codes in the Hamming graphs K-q(n). They stated, for instance, that gamma(ID)(K-q(n)) <= q(n-1) for any q and n >= 3. Moreover, they conjectured that gamma(ID)(K-q(3)) = q(2). In this article, we show that gamma(ID)(K-q(3)) <= q(2) - q/4 when q is a power of four, which disproves the conjecture. Goddard and Wash also gave the lower bound gamma(ID)(K-q(3)) >= q(2) - q root q. We improve this bound to gamma(ID)(K-q(3)) >= q(2) - 3/2q. Moreover, we improve the above mentioned bound gamma(ID)(K-q(n)) <= q(n-1) to gamma(ID)(K-q(n)) <= q(n-k) for n = 3 q(k)-1/q-1 and to gamma(ID)(K-q(n)) <= 3q(n-k) for n = q(k)-1/q-1, when q is a prime power. For these bounds, we utilize two classes of closely related codes, namely, the self-identifying and the self-locating-dominating codes. In addition, we show that the self-locating-dominating codes satisfy the result gamma(SLD)(K-q(3)) = q(2) related to the above conjecture.
Year
DOI
Venue
2019
10.37236/7828
ELECTRONIC JOURNAL OF COMBINATORICS
Keywords
Field
DocType
Hamming graph,identifying code,linear codes over finite fields,Latin square,location-domination
Discrete mathematics,Combinatorics,Conjecture,Hamming graph,Mathematics
Journal
Volume
Issue
ISSN
26
2
1077-8926
Citations 
PageRank 
References 
0
0.34
0
Authors
3
Name
Order
Citations
PageRank
Ville Junnila14310.51
Tero Laihonen236339.39
Tuomo Lehtilä322.06