Symmetry and classification of certain regular group divisible designs

Abstract

In this paper it is shown that a regular group divisible (GD) design, with parametersv, b, r, k, ? 1, ?2 satisfyingrk ? ?2 v + 1 and? 2 = ?1 + 1, must be symmetric (i.e.,v + b). Furthermore, the parameters of such symmetric regular GD designs can be expressed in terms of only two integral parameters.