A.T. Fomenko, Double cover of the Klein bottle by torus
Pasha Zusmanovich

6/7TOPO Topology, winter semester 2026/2027

Thursday 09:10-10:45  G503

LITERATURE
Main: Additional: All the books are available in electronic form.          = available in the university library

A BRIEF SYNOPSIS
(Each class lasted approximately 1.5 hours, unless specified otherwise; tutorials are running separately)

Class 1 September 23, 2026
Organizational details. The subject of topology. Definition of a topological space. Examples of topological spaces: trivial and discrete toplogy, topologies on 2- and 3-element sets, the standard topology on \(\mathbb R\), chain topology. Number of topologies on a finite set.
([V], pp. xi-xii, 2, 11-12; Munkres, p.76)

Class 2 September 29, 2026
Closed sets, definition of topology in terms of closed sets. Clopen sets. A parody of an episode from the movie "The Bunker" featuring clopen sets. Base of a topology, examples. The standard base of the standard topology on \(\mathbb R\) can be decreased.
([V], pp.13-14,16)

Class 3 October 1, 2026
Any base of the standard topology on \(\mathbb R\) can be decreased. Criteria for a family of open sets to be a base ([V], 3.A, 3.B, 3.C).
([V], pp.16-17)

Class 4 October 6, 2026
Topological spaces with small number of bases. Finer and coarser topologies. Criterion for a topology to be coarser (Munkres, Lemma 13.3). The standard topology on \(\mathbb R^2\).
([V], pp.16-17; Munkres, p.81).

Class 5 October 8, 2026
Non-existence of a topological space having exactly 3 bases (redo). Metric spaces. Euclidean metric, Manhattan metric, 0-1 metric. Restriction of a metric to a subspace. Balls and spheres.
([V], pp.18-20).

Class 6 October 9, 2026
Finite metric spaces. Metric topology. Proof that the metric topology is well-defined (open balls form a base of the topology). Examples of metric topologies.
([V], pp.20,22; Munkres, pp.119-120).


EXAM
TBD


A brief synopsis, videos, and homeworks from this course at the previous semesters


Created: Fri Oct 2 2020
Last modified: Thu Oct 15 2026 15:14:03 CEST