On constructions and parameters of symmetric configurations $$v_{k}$$vk

The spectrum of possible parameters of symmetric configurations is investigated. We propose some new constructions, mainly based on Finite Geometry and on extension methods. New parameters are provided, both for general symmetric configurations and for cyclic symmetric configurations. For several values of $$k$$k, new upper bounds on the minimum integer $$E$$E such that for each $$v\ge E$$v≥E there exists a (cyclic) symmetric configuration $$v_{k}$$vk are obtained.