A new upper bound for the isoperimetric number of deBruijn Networks Original Research Article

Delorme and Tillich found an upper bound and a lower bound for the isoperimetric number in(d) of deBruijn Networks over the alphabet {0,1,…,d − 1} using eigenvalue techniques (see [1]). We improve their upper bound for in(d) and give constructions for the sets of vertices of the deBruijn Network, which lead to our bound.