Have you ever asked someone a question only to find that they asked you the same question a few months earlier? Well that happened in our research group today when Michael and I knocked on Pablo Spiga’s door to ask him whether he knows of a particular type of strongly regular Cayley graph. Deja vu immediately hit us, and the rest is a shameful example of a poor memory. Anyway, here is the problem that the three of us do not know the answer to, but for which someone out there might enlighten us.
Does there exist a strongly regular Cayley graph Cay(G, S) where G is a nonabelian simple group?