An improved lower bound for (1,≤2)-identifying codes in the king grid




Foucaud F, Laihonen T, Parreau A

PublisherAMER INST MATHEMATICAL SCIENCES

2014

Advances in Mathematics of Communications

ADVANCES IN MATHEMATICS OF COMMUNICATIONS

ADV MATH COMMUN

8

1

35

52

18

1930-5346

DOIhttps://doi.org/10.3934/amc.2014.8.35



We call a subset C of vertices of a graph G a (1, <= l)-identifying code if for all subset X of vertices with size at most l, the sets {c is an element of C vertical bar there exists u is an element of X, d(u, c) <= 1} are distinct. The concept of identifying codes was in in 1998 by Karpovsky, Chakrabarty and Levitin. Identifying codes have been studied in various grids. In particular, it has been shown that, there exists a (1, <= 2)-identifying code in the king grid with density (3)(7) and that there are no such identifying codes with density smaller than 5/12. Using a suitable frame and a discharging procedure, we improve the lower bound by showing that any (1, <= 2)-identifying code of the king grid has density at least 47/111. This reduces the gap between the best known lower and upper bounds on this problem by more than 56%.




Last updated on 2024-26-11 at 22:04