Alexander L. Gavrilyuk

collaborators

3 papers

math.CO2019

On the multiplicities of digraph eigenvalues

Alexander L. Gavrilyuk, Sho Suda

We show various upper bounds for the order of a digraph (or a mixed graph) whose Hermitian adjacency matrix has an eigenspace of prescribed codimension. In particular, this general…

math.CO2019

On few-class $Q$ -polynomial association schemes: feasible parameters and nonexistence results

Alexander L. Gavrilyuk, Janoš Vidali, Jason S. Williford

We present the tables of feasible parameters of primitive $3$ -class $Q$ -polynomial association schemes and $4$ - and $5$ -class $Q$ -bipartite association schemes (on up to $2800$ , $1…

math.CO2018

On tight $4$ -designs in Hamming association schemes

Alexander Gavrilyuk, Sho Suda, Janoš Vidali

We complete the classification of tight $4$ -designs in Hamming association schemes $H (n, q)$ , i.e., that of tight orthogonal arrays of strength $4$ , which had been open since a resu…

On the multiplicities of digraph eigenvalues

On few-class Q-polynomial association schemes: feasible parameters and nonexistence results

On tight 4-designs in Hamming association schemes

On few-class $Q$ -polynomial association schemes: feasible parameters and nonexistence results

On tight $4$ -designs in Hamming association schemes