Bruck-Ryser Abstract Theorem and Symmetric Designs

In [3] U. Ott introduced a Bruck-Ryser abstract theorem concerning "lattices of an R-module". As one of the applications of this theorem, he obtained a new proof of the Bruck-Ryser theorem for finite projective planes and studid "p-curves" in a projective plane. In this paper, we apply the Bruck-Ryser abstract theorem in order to give a new proof of the Bruck-Ryser-Chowla theorem for symmetric (v.k,lambda)-designs with (v,k,lambda)=1, and to study "p-curves" in arbitrary symmetric designs.