  Permutation arrays under the Chebyshev metric have been considered for error
correction in noisy channels. Let $P(n,d)$ denote the maximum size of any array
of permutations on $n$ symbols with pairwise Chebyshev distance $d$. We give
new techniques and improved upper and lower bounds on $P(n,d)$, including a
precise formula for $P(n,2)$.
