Difference sets satisfying the Deza Cayley graph parameter condition
Determine whether there exist difference sets in abelian groups, other than the known examples, with parameters $(v,k,\lambda)$ satisfying $k=\frac{2v-1-\sqrt{8v-7}}{2}$, so that the associated generalized dihedral Cayley graph is a strictly Deza graph.
References
We do not know whether there exist other DSs satisfying the condition $k=\frac{2v-1-\sqrt{8v-7}}{2}$. Checking using the database of DSs implies that there is no other such a DS with $v\leq 10000$.
— Deza Cayley graphs from difference sets
(2506.10440 - Ryabov, 12 Jun 2025) in Section 3.1, immediately following Corollary 3 (the corollary labeled \ref{dsgraphs})