An application of modified group divisible designs

Modified group divisible designs with block size four

The existence of modiied group divisible designs with block size four is settled with a handful of possible exceptions.

Resolvable Modified Group Divisible Designs with Block Size Three

A resolvable modified group divisible design (RMGDD) is an MGDD whose blocks can be partitioned into parallel classes. In this article, we investigate the existence of RMGDDs with block size three and show that the necessary conditions are also sufficient with two exceptions. # 2005 Wiley Periodicals, Inc. J Combin Designs 15: 2–14, 2007

Resolvable modified group divisible designs with higher index

A resolvable modified group divisible design (RMGD) is a modified group divisible design whose blocks can be partitioned into parallel classes. We show that the necessary conditions for the existence of a 3-RMGDDλ of type g, namely g ≥ 3, u ≥ 3, gu ≡ 0 mod 3 and λ(g−1)(u−1) ≡ 0 mod 2, are sufficient with the two exceptions of (g, u, λ) ∈ {(6, 3, 1), (3, 6, 1)}.

Construction of Group Divisible Designs

Divisible designs with dual translation group

Many different divisible designs are already known. Some of them possess remarkable automorphism groups, so called dual translation groups. The existence of such an automorphism group enables us to characterize its associated divisible design as being isomorphic to a substructure of a finite affine space. AMS Classification: 05B05, 05B30, 20B25, 51N10