Publications [#236019] of Robert Calderbank

Papers Published

1. Calderbank, AR, Geometric invariants for quasi-symmetric designs, Journal of Combinatorial Theory Series A, vol. 47 no. 1 (January, 1988), pp. 101-110, Elsevier BV, ISSN 0097-3165 [doi]
   (last updated on 2026/01/17)

   Abstract:
   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.