Two Results Concerning Distance-Regular Directed Graphs

Author

D. Combe and D. E. Taylor

Status

Research Report 99-13
Date: 10 June 1999

Abstract

The study of distance-regular directed graphs can be reduced to that of short distance-regular directed graphs. We consider the eigenspaces of the intersection matrix of a short distance-regular directed graph and show that nearly all the eigenvalues are nonreal. Next we show that a nontrivial short distance-regular directed graph is primitive.

Key phrases

distance-regular graph. distance-transitive graph. directed graph. primitivity. adjacency algebra.

AMS Subject Classification (1991)

Primary: 05C20
Secondary: 05C25, 05E30

Content

The paper is available in the following forms:

TeX dvi format:: 1999-13.dvi.gz (16kB) or 1999-13.dvi (37kB)
PostScript:: 1999-13.ps.gz (40kB) or 1999-13.ps (134kB)

To minimize network load, please choose the smaller gzipped .gz form if and only if your browser client supports it.

Sydney Mathematics and Statistics