News
ExamsGeschrieben am 22.02.24 von Gabriela WeitzeSchmithuesen Dear participants,
it seems that all of you prefer to have the exam in April. Therefore I have chosen Wednesday April 10 as the day for the exams. If you would like to take the exam but that day does not work for you, please let me know.
Gabriela WeitzeSchmithüsen 
Lecture again in SR 9Geschrieben am 08.02.24 von Gabriela WeitzeSchmithuesen Dear participants, the lecture today will be again in SR 9 (at 10 pm). Gabriela WeitzeSchmithüsen

Lecture tomorrowGeschrieben am 31.01.24 von Gabriela WeitzeSchmithuesen Dear participants,
the lecture tomorrow (at 10.15) will take place in Seminarraum 9. Best, Gabriela WeitzeSchmithüsen 
Lecture tomorrowGeschrieben am 24.01.24 von Gabriela WeitzeSchmithuesen Dear participants,
as a reminder: the lecture tomorrow will be at 10:15 am. It will take place in Seminarraum SR8. (on the same floor as SR10).
Best, Gabriela WeitzeSchmithüsen 
Geschrieben am 13.12.23 von Gabriela WeitzeSchmithuesen Reminder: Today and tomorrow are no lectures! 
This week no lecturesGeschrieben am 11.12.23 von Gabriela WeitzeSchmithuesen Dear participants, as announced in the last lecture there will be no lecture this week. I will put you some reading suggestions in the CMS. We will talk about them next week. Best , Gabriela WeitzeSchmithüsen 
Mistake in Sheet 5Geschrieben am 01.12.23 von Pascal Kattler There was a mistake in exercise 3 of sheet 5. The map from A to Z/2Z must not be injective. 
Ausstellungseröffnung heuteGeschrieben am 03.11.23 von Gabriela WeitzeSchmithuesen Dear participants,
here comes as promised the link to the exhibition launch today: https://www.imaginary.org/de/node/2558 It starts at 4pm in GünterHotzHörsaal. After the talks there will be a gathering with some canapés and drinks.
You are very welcome to joins… Weiterlesen Dear participants,
here comes as promised the link to the exhibition launch today: https://www.imaginary.org/de/node/2558 It starts at 4pm in GünterHotzHörsaal. After the talks there will be a gathering with some canapés and drinks.
You are very welcome to joins us!
Gabriela WeitzeSchmithüsen

Exercise sessionGeschrieben am 02.11.23 von Pascal Kattler The exercise session will be in Seminarraum 6. 
Geschrieben am 31.10.23 von Pascal Kattler There was a small mistake in exersice 1(b) of sheet 1. c should also not be zero. 
Exercise sessionGeschrieben am 30.10.23 von Pascal Kattler The exercise session will be at monday 12 pm. The first exercise session will be at 06.11.2023. 
Geometric Group Theory
Dates:
 Lecture: Wednesday, 10 am (c.t.) and Thursday, 2pm (c.t.) in SR 10 (Building E 2.4)
 Exercise Section: to be anounced
The Team:
 Lecturer: Prof. Dr. Gabriela WeitzeSchmithüsen (weitze [at] math.unisb.de)
 Assistant: Pascal Kattler (nachname [at] math.unisb.de)
 Tutor: Robin Lahni
Prerequisites:
Linear Algebra I und II and Algebra (recommended).
Topic:
The Geometric group theory is a relatively new mathematical discipline which builds interesting connections between group theory and geometry. Its goal is to study groups using geometric methods. There are two main approaches:
 Study how a group acts on a suitable geometric space.
 Consider the group itself as a geometric space.
The interaction of these two fields has lead to a series of mathematical breakthroughs in the last 50 years, among them Gromov's program to classify finitely generated groups, the systematic study of closed three manifolds by William Thurston, the solution of the isomorphism problem of word hyperbolic groups by Sela and the proof of the Haken conjecture by Ian Agol. The theory of automata groups closely links geometric group theory to computer sciences.
This lecture is a first introduction to geometric group theory. We will introduce Cayley graphs, the theory of quasiisometries and the socalled coase geometry. Some highlights will be the theorem of Schwarz and Milnor which relates geometric properties of the group to geometric spaces on which it acts in a good way, as well as examples of groups which play an eminent role in current research. This will offer insights into a rich world between algebra and geometry.
The lecture is a new Stammvorlesung which gives access to the mathematical disciplines of the two lecturer. It is aimed at bachelor and master students. With its algorithmic aspects it can also be an interesting lecture for students in computer sciences.
Contents:
 Free groups, presentations of groups, Cayley graphs
 Fundamental groups and covering theory
 Coarse geometry, quasiisometries ad the theorem of Milnor and Schwarz
 Gromov hyperbolicity
 Optional: Growth of groups, space of ends, Fuchsian groups, Example of geometric spaces as Teichmüller space, translation surfaces and outer space.
Literature:

Pierre de la Harpe: Topics in Geometric Group Theory, Chicago Lectures in Mathematics 2003

Clara Löh: Geometric Group Theory, SpringerVerlag 2017
Supplementary Literature:
 Otto Forster: Lectures on Riemann Surfaces (e.g. for theory of coverings, universal covering)
 Roger C. Lyndon , Paul E. Schupp: Combinatorial Group Theory (e.g. for group presentations, free products with amalgamation, HNN extensions)
 John Stillwell: Classical Topology and Combinatorial Group Theory (e.g. for fundamental groups, Theorem Seifert/van Campen, classification of closed surfaces, Dehn algorithm for surface groups)
 L. Christine Kinsey: Topology of Surfaces (e.g. for classification of closed surfaces)