A family of relative difference sets associated with Hjelmslev structures over finite projective spaces (Q918551)

A new construction for relative difference sets gives one (and more) family of symmetric divisible designs with a natural epimorphism into a projective space (taking hyperplans as blocks): these are the first examples of balanced non-uniform c-H-structures of type 2 [see \textit{D. A. Drake} and \textit{D. Jungnickel}: Klingenberg structures and partial designs I. Congruence relations and solutions, J. Stat. Plan. Inference 1, 265-287 (1977; Zbl 0426.05017)]. The ideas of the paper seems to have many applications, and some other development is only sketched.