Double coset Schur rings and diagonal subgroups
We investigate the structure of Schur rings arising from group triples $(G, H, K)$, where $K \trianglelefteq H \leq G$, building on foundational work by Brender and Travis. Central to our approach is the interplay between Schur rings and (strong) Gelfand pairs. We introduce certain double coset algebras, and illustrate...