G-ekuvaryant liflemeler üretmenin engel teorisi

In this thesis, we develop an obstruction theory for constructing G-fibrations with a prescribed fiber over a given G-CW-complex. Constructing G-fibrations with a prescribed fiber is an important step in the construction of free G-actions on finite CW-complexes which are homotopy equivalent to a product of spheres.In this thesis, we also consider the following question: For which finite groups the Euler class of the spherical fibration of the reduced regular representation is non-zero? This question was raised by Reiner and Webb and we answer this question completely.