Relative difference sets suitable for Deza Cayley graph constructions

Construct or identify additional relative difference sets satisfying the parameter conditions in Proposition \ref{rds}, thereby yielding further Deza Cayley graphs over generalized dihedral groups.

Background

Proposition \ref{rds} gives two constructions of Deza Cayley graphs from a nontrivial relative difference set RR in an abelian group with a nontrivial forbidden subgroup. The first construction requires (n,λ)=(2,2)(n,\lambda)=(2,2) or (4,2)(4,2), while the second requires λ=2\lambda=2.

Lemma \ref{smallrds} supplies several families and examples of relative difference sets meeting these conditions, and Corollary \ref{rdsgraphs} converts them into strictly or non-strictly Deza Cayley graphs. After listing the resulting graphs, the paper states that no further suitable relative difference sets had been found, leaving the search for additional examples unresolved.

References

We are not able to find other RDSs which satisfy the conditions from Proposition~\ref{rds} and hence can be used for constructing Deza Cayley graphs.

Deza Cayley graphs from difference sets  (2506.10440 - Ryabov, 12 Jun 2025) in Section 3.2, immediately following Corollary 5 (the corollary labeled \ref{rdsgraphs})