On commutative association schemes and associated (directed) graphsMonzillo, Giusy (Avtor) Penjić, Safet (Avtor) commutative association schemesassociation schemesBose-Mesner algebraequitable partitiongraphs generating schemesquotient-polynomial graphsx-distance-faithful intersection diagramLet ${\mathcal M}$ denote the Bose--Mesner algebra of a commutative $d$-class association scheme ${\mathfrak X}$ (not necessarily symmetric), and $\Gamma$ denote a (strongly) connected (directed) graph with adjacency matrix $A$. Under the assumption that $A$ belongs to ${\mathcal M}$, we describe the combinatorial structure of $\Gamma$. Moreover, we provide an algebraic-combinatorial characterization of $\Gamma$ when $A$ generates ${\mathcal M}$. Among else, we show that, if ${\mathfrak X}$ is a commutative $3$-class association scheme that is not an amorphic symmetric scheme, then we can always find a (directed) graph $\Gamma$ such that the adjacency matrix $A$ of $\Gamma$ generates the Bose--Mesner algebra ${\mathcal M}$ of ${\mathfrak X}$.20252025-09-26 11:03:16Članek v reviji21794UDK: 519.17ISSN pri članku: 1077-8926DOI: 10.37236/12973COBISS.SI-ID: 231013635sl