Deletions, extensions, and reductions of elliptic semiplanes
M. Abreu, Martin Funk, D. Labbate, Vito Napolitano · Innovations in incidence geometry · 2010
We present three constructions which transform some symmetric configuration K of type n k into new symmetric configurations of types (n + 1) k , or n k-1 , or ((λ -1)µ) k-1 if n = λµ.Applying them to Desarguesian elliptic semiplanes, an infinite family of new configurations comes into being, whose types fill large gaps in the parameter spectrum of symmetric configurations.