ON THE SPECTRUM OF t-(v,k) LATIN TRADES

The concept of t-(u,k) trade of block designs previously has been studied in detail. See for example (2). Also latin trades has been studied in detail under different names, see (4) for a survey. Khanban, mahdian and mahmoodian (3) extended the concept of latin trades and intriduced t-(v,k) latin trades, S(t,k). First, we define (t+1) numbers si=2t+1-2t-i, 0≤i≤t-1, then s∉ S(t,k). Also, we show that if s