Constructions and topological invariants of 2-(v,3,\(\lambda\) ) designs with group actions (Q1093637)

Methods for constructing and distinguishing 2-designs using topological invariants are given in the paper. The authors find invariants of a design \(\tilde {\mathcal B}\) in terms of a topological structure associated with a predesign \({\mathcal B}\) (a family of generalized difference sets). When designs have a natural group of actions with 0 or 1 fixed points these invariants are easily computed and methods of constructing 2- (v,3,\(\lambda)\) designs with such a group action are given.