Am × k matrixA, with entries from a set ofq ? 2 elements, is called an orthogonal arrayOA(m, k, q, t) (t ? 2) if eachm × t submatrix ofA contains all possible 1 ×t row vectors with the same frequency?(m = ?q t ). We call the array schematic if the set of rows ofA forms an association scheme with the relations determined by the Hamming distance. In this paper we determine the schematic orthogonal arraysOA(q t ,k, q, t) with2t ? 1 > k.
['Mitsuo Yoshizawa']
On schematic orthogonal arraysOA(qt,k, q, t)