Use of complementary property of block designs in PBIB designs

Some results on combinatorial aspects of block designs using the complementary property have been obtained. The results pertain to nonexistence of partially balanced incomplete block (PBIB) designs and identification of new 2-associate and 3-associate PBIB designs. A method of construction of extended group divisible (EGD) designs with three factors using self-complementary rectangular designs has also been given. Some rectangular designs have also been obtained using self-complementary balanced incomplete block designs. Catalogues of EGD designs and rectangular designs obtainable from these methods of construction, with number of replications r <= 10 and block size k <= 10 have been prepared.