10 papers
Divisible design graphs obtained by plugging a difference set into a construction for antipodal distance-regular graphs of diameter 3
Bart De Bruyn, Sergey Goryainov, Ruilin Ma +1
In this paper, we present a new construction of divisible design graphs with new parameters, obtained by plugging a difference set of a quotient group into a known construction of…
Cliques in Paley graphs of square order and in Peisert graphs
Andries E. Brouwer, Sergey Goryainov, Leonid Shalaginov +1
We study maximal cliques in the collinearity graphs of Desarguesian nets, give some structural results and some numerical information. In particular, we show for Desarguesian nets…
The spectral Turán problem: Characterizing spectral-consistent graphs
Longfei Fang, Sergey Goryainov, Denis Krotov +2
Let and denote the families of -vertex -free graphs with the maximum size and the maximum spectral radius, respectively. A graph is said…
A family of Neumaier graphs containing examples with exactly five eigenvalues
Bart De Bruyn, Rhys J. Evans, Sergey Goryainov +1
A Neumaier graph is an edge-regular graph with a regular clique. Such a graph is said to have parameters if it is a -regular graph on vertices having a clique…
On Neumaier Cayley graphs
Rhys J. Evans, Sergey Goryainov, Grigory Ryabov +1
In the present paper, we study Neumaier Cayley graphs. First, we give a criterion for a Cayley graph to be a Neumaier graph with a spread given by the cosets of a subgroup. Further…
Thin divisible designs graphs: an interplay between fixed-point free involutions of -graphs and symmetric weighing matrices
Sergey Goryainov, Willem H. Haemers, Elena V. Konstantinova +1
In this paper, we illustrate important aspects of the interplay between weighing matrices, -graphs with fixed-point free involutions, and signed graphs with an orthogonal…