Group divisible designs with block size four and group type gum1 for small g Original Research Article

In this paper, we continue to investigate the spectrum for {4}-GDDs of type gum1 with small g. We show that, for each g∈{2,4,5,12,15} and each admissible pair (u,m), a {4}-GDD of type gum1 exists with a definite exception for (g,u,m)=(2,6,5) and 5 possible exceptions when g=2.