Introduction to Topology

  • Instructor: Ágnes SZILARD PhD
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  • Prerequisites: Solid knowledge of calculus (limits and continuity, manipulating with sets and fuctions) is indispensable. Rudiments of group theory (uderstanding of what a group, homomorphism, isomorphism is, as well as familiarity with basic groups such as cyclic groups, Z, ZxZ) will also be necessary in the second half of the course.
  • Text: notes will be posted

Course description: This is a standard introductory course the goal of which is to get acquainted with the basic notions of the field. Thus we start with point-set topology and the study of topological spaces, in particular metric spaces, continuity, connectedness, compactness. The machinery developed will allow us to consider one of the major theorems of topology: the classification of compact, connected surfaces. In the second half of the course we get a taste of algebraic topology - the notion of the fundamental group of a topological space will be introduced as well as several ways of computing it. Throughout the course we will study numerous examples and applications.


  • Topological spaces, homeomorphism. First examples. The classification problem and the role of topological invariants.
  • Constructing new topologies from given ones: the subspace, quotient and product topologies.
  • Some topological invariants: the Hausdorff property, compactness, connectedness, path-connectedness.
  • Compact, connected surfaces. Euler characteristic and orientability. The classification theorem of compact connected surfaces.
  • The fundamental group. Intuitive examples.
  • Methods to calculate the fundamental group: covering spaces, retracts and deformation retracts.
  • If time permits: properly discontinuous group actions.