4 papers
On the combinatorial structure of graphs with a spectral idempotent of small dual diameter
Edwin R. van Dam, Giusy Monzillo, Safet Penjić
Let be a connected regular graph with an eigenvalue and corresponding idempotent . Let be the algebra generated by and $E_λ…
On Hoffman polynomials of -doubly stochastic irreducible matrices and commutative association schemes
Giusy Monzillo, Safet Penjić
Let denote a finite (strongly) connected regular (di)graph with adjacency matrix . The {\em Hoffman polynomial} of is the unique polynomial of smallest degre…
On commutative association schemes and associated (directed) graphs
Giusy Monzillo, Safet Penjić
Let denote the Bose--Mesner algebra of a commutative -class association scheme (not necessarily symmetric), and denote a (strongly) connected (dir…
On certain regular nicely distance-balanced graphs
Blas Fernandez, Štefko Miklavič, Safet Penjić
A connected graph $\G$ is called {\em nicely distance--balanced}, whenever there exists a positive integer $γ=γ(\G)$, such that for any two adjacent vertices of $\G$ there ar…