We consider the degree-diameter problem for undirected and directed circulant graphs. To date, attempts to generate families of large circulant graphs of arbitrary degree for a given diameter have concentrated mainly on the diameter 2 case. We present a direct product construction yielding improved bounds for small diameters and introduce a new general technique for “stitching” together circulant graphs which enables us to improve the current best known asymptotic orders for every diameter. As an application, we use our constructions in the directed case to obtain upper bounds on the minimum size of a subset A of a cyclic group of order n such that the k-fold sumset kA is equal to the whole group. We also present a revised table of largest known circulant graphs of small degree and diameter.
|Number of pages||17|
|Journal||Ars Mathematica Contemporanea|
|Early online date||9 Mar 2017|
|Publication status||E-pub ahead of print - 9 Mar 2017|
- degree-diameter problem
- circulant graphs
- Cayley graphs