科研之友
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摘要
A group divisible design GD(k, lambda, t; tn) is alpha-resolvable if its blocks can be partitioned into classes such that each point of the design occurs in precisely a blocks in each class. The necessary conditions for the existence of such a design are n >= k, lambda t(n - 1) = r(k - 1), bk = rtn, k vertical bar alpha tn and alpha vertical bar r. It is shown in this paper that these conditions are also sufficient when k = 4 and t = 3, except for n = 4 and alpha = lambda = 1.
