Publications [#236019] of Robert Calderbank

Journal articles or Book chapters PUBLISHED
  1. Calderbank, AR, Geometric invariants for quasi-symmetric designs, Journal of Combinatorial Theory, Series A, vol. 47 no. 1 (1988), pp. 101-110 .

    Let p be an odd prime. We derive new necessary conditions for the existence of 2 - (ν, k, λ) designs where the block intersection sizes s1, s2, ..., sn satisfy s1 ≡ s2 ≡ ... ≡ sn (mod p). The method is to define a nondegenerate scalar product on a 2m-dimensional vector space and to construct an m-dimensional totally singular subspace. This result is a generalization to nonsymmetric designs of the Bruck-Ryser-Chowla theorem. © 1988.