  Brown, Nowakowski and Rall defined the ultimate categorical independence
ratio of a graph G as A(G)=\lim_{k\to \infty} i(G^{\times k}), where
i(G)=\frac{\alpha (G)}{|V(G)|} denotes the independence ratio of a graph G, and
G^{\times k} is the k-th categorical power of G. Let
a(G)=\max{\frac{|U|}{|U|+|N_G(U)|}: U is an independent set of G}}, where
N_G(U) is the neighborhood of U in G. In this paper we answer a question of
Alon and Lubetzky, namely we prove that if a(G)\le 1/2 then A(G)=a(G), and if
a(G)>1/2 then A(G)=1. We also discuss some other open problems related to A(G)
which are immediately settled by this result.
