Topology

SS 2026

Docent: Tanja Eisner

Lectures: Mi 9:15-10:45, SG 3-13

Requirement: Analysis I

Description

Topology is a branch of mathematics that serves as the basis for many other areas of mathematics such as analysis, geometry, and algebra. The aim of this course is to provide an introduction to general topology.

The following topics will be covered, among others: basic constructions, convergence (using nets and filters) and continuity, separation axioms, metrizability, compactness (compactness via open covers versus sequential compactness and countable compactness, Tichonoff's theorem), compactifications (Alexandroff and Stone-Čech compactification), the space βN, continuous functions (Urysohn's lemma, Tietze-Urysohn theorem, partitions of unity), Baire spaces.

Notes

8-15.4., 22.4.-13.5., 20-27.5., 3-10.6., 17.6.-8.7.

Seminar

Topics with literature

Schedule

26.5. (Di) 13:15-14:45 (S 015): "Baire spaces and topological games" (Matthes Debes*, Marvin Polster*)

27.5. (Mi) 13:15-14:45 (S 110): "A typical continuous function is nowhere differentiable" (Leon-Emilio Erinsk*) and "Hopf fibration" (Simon Schmitt*)

                 15:15-16:45 (S 110): "Tychonoff's theorem" (Jakob Linnemann, Christina Wiehler)

09.6. (Di) 13:15-14:45 (S 015): "Ultrafilters as a topological space and the Stone-Cech compactification" (Hazel Rosengrün*, Manuel Westphal*)

10.6. (Mi) 13:15-14:45 (S 015): "Algebraic structure of filters and ultrafilters" (Ben Duyster*) and "Structure of semitopological semigroups" (Ann-Kristin Habermann)

23.6. (Di) 13:15-14:45 (S 015): "Applications of ultrafilters to faire voting" (Bruno Nitsch) and "Ramsey's theorem on colouring of graphs" (Minahil Zaidi*)

30.6. (Di) 13:15-14:45 (S 015): "Hindman's theorem via ultrafilters" (Rudolf Braun*) and "Van der Waerden's theorem via ultrafilters" (Benjamin Piesbergen)

* = talk in English

Literature

Kazimierz Kuratowski

Andrey N. Tikhonov

Georg Cantor

Felix Hausdorff