On the number of maximum independent sets in Doob graphs

Abstract

The Doob graph $D(m,n)$ is a distance-regular graph with the same parameters as the Hamming graph $H(2m+n,4)$. The maximum independent sets in the Doob graphs are analogs of the distance-$2$ MDS codes in the Hamming graphs. We prove that the logarithm of the number of the maximum independent sets in $D(m,n)$ grows as $2^{2m+n-1}(1+o(1))$. The main tool for the upper estimation is constructing an injective map from the class of maximum independent sets in $D(m,n)$ to the class of distance-$2$ MDS codes in $H(2m+n,4)$.

5 pages, 2 figures

References in corpus (1)

• Distance-2 MDS codes and latin colorings in the Doob graphs

Cited by in corpus (2)

• To the theory of $q$-ary Steiner and other-type trades
• Distance-2 MDS codes and latin colorings in the Doob graphs