Some results on Bhaskar Rao designs

A Bhaskar Rao design is a v × b matrix of 0’s, 1’s and −1’s such that the inner product of any two rows is known and the matrix obtained by squaring the entries is the incidence matrix of a partially balanced incomplete block design with m associate classes. Two applications of these designs to the construction of other partially balanced incomplete block designs are presented. Some necessary conditions and construction methods for Bhaskar Rao designs are given.