The Fundamental Groups and Classification of Covering Spaces

Abstract

Algebraic topology is a very rich subject and its beauty lies in the way chosen to study space. Based on the global properties of spaces, the constructions and developments in this subject give an abstract and general notion. Defining algebraic topology as the study of topological spaces by using the algebraic invariants is the very basic interpretation of algebraic topology. However, the fundamental group is one of these topological invariants used to study topological spaces. The algebraic variants such as fundamental group are used for the classification of topological spaces up to the homeomorphism. However, most of the invariants classify topological spaces up to homotopy equivalence. The general idea of algebraic topology and fundamental group has been given in the 1st chapter. In this thesis work, to explain fundamental group, homeomorphism, and homotopy, the 2nd chapter includes the gathered ideas and concepts of homotopy of loops and maps, fundamental group, and induced homeomorphism. This chapter forms a basis for covering spaces which has a direct link with the fundamental group. After setting the basis for covering spaces, the 3rd chapter explains all the aspects related to covering spaces such as the lifting of maps to the covering space, and the applications of the fundamental group are explained through the major algebraic topology theorems; “Brouwer Fixed Point Theorem” and “Borsuk Ulam Theorem”. A main result named as “Van-Kampan Theorem” has also been proved which helps a lot to calculate the fundamental groups of different spaces. In chapter 4 all the possible covering spaces of the given topological space have been discussed leading to the classification of covering spaces. Moreover, this section discusses the classification of covering spaces by starting from “The Covering Transformation”, “Galois Covering Space”, “Universal Cover” and “Galois Correspondence”.