Enumeration of digraphs with given number of vertices of odd out-degree and vertices of odd in-degree

The distance spectral radius of graphs with given number of odd vertices

Tetravalent edge-transitive Cayley graphs with odd number of vertices

A characterisation is given of edge-transitive Cayley graphs of valency 4 on odd number of vertices. The characterisation is then applied to solve several problems in the area of edge-transitive graphs: answering a question proposed by Xu (1998) regarding normal Cayley graphs; providing a method for constructing edge-transitive graphs of valency 4 with arbitrarily large vertex-stabiliser; const...

Vertices of given degree in a random graph

The asymptotic distributions of the number of vertices of given degree in random graph K n,p are given. By using the method of Poisson convergence, Poisson and normal distributions are obtained.

Double Dudeney sets for an odd number of vertices

A double Dudeney set in Kn is a multiset of Hamilton cycles in Kn having the property that each 2-path in Kn lies in exactly two of the cycles. In this paper, we construct a double Dudeney set in Kn when n = p1p2 · · · ps + 2, where p1, p2, . . . , ps are different odd prime numbers and s is a natural number.

Vertices of given degree in series-parallel graphs

We show that the number of vertices of a given degree k in several kinds of series-parallel labelled graphs of size n satisfy a central limit theorem with mean and variance proportional to n, and quadratic exponential tail estimates. We further prove a corresponding theorem for the number of nodes of degree two in labelled planar graphs. The proof method is based on generating functions and sin...