We present constructions and results about GDDs with two groups and block size five in which each block has Configuration (s, t), that is, in which each block has exactly s points from one of the twoâ€¦ (More)

We show the necessary conditions are su6cient for the existence of GDD(n; 2; 4; 1, 2) with two groups and block size four in which every block intersects each group exactly twice (even GDDâ€™s) or inâ€¦ (More)

We give some constructions of new infinite families of group divisible designs, GDD(n, 2, 4; 1, 2), including one which uses the existence of Bhaskar Rao designs. We show the necessary conditions areâ€¦ (More)

Under the right conditions it is possible for the ordered blocks of a path design PATH(v, k, ) to be considered as unordered blocks and thereby create a BIBD(v, k, ).We call this a tight embedding.Weâ€¦ (More)

In this paper, we consider balanced ternary designs, BTDs, in which every block contains one element singly and the rest doubly. We call these packed BTDs, and we investigate three aspects of theseâ€¦ (More)