Doubly regular asymmetric digraphs
Let \(D=(P,B)\) be a symmetric design where P and B are the sets of points and blocks, respectively. If T is a bijection from B to P satisfying the conditions i) for every block a, T(a)\(\not\in a\), ii) if T(a)\(\in b\), then T(b)\(\not\in a\), then the author associates with D a digraph G in the following way: the set of vertices of G equals P and (u,v) is an arc of G if \(v\in T^{-1}(u).\) In the paper some basic properties of the graphs obtained in this manner are shown.
scientific article; zbMATH DE number 4079452
scientific article