Abstract:
We derive new estimates of the size of codes and orthogonal arrays in the ordered Hamming space (the Niederreiter–Rosenbloom–Tsfasman space). We also show that the eigenvalues of the ordered Hamming scheme, the association scheme that describes the combinatorics of the space, are given by the multivariate Krawtchouk polynomials, and establish some of their properties.
Key words and phrases:ordered Hamming space, association schemes, multivariate Krawtchouk polynomials, Delsarte method, asymptotic bounds.