BIREP – Representations of finite dimensional algebras at Bielefeld
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BIREP Summer School on Gentle Algebras

14 August – 18 August 2017

Gentle Algebras

Location: Hotel Waldcafé Jäger, Bad Driburg

Invited speaker: Prof. Christof Geiß

Organisers: Ögmundur Eiriksson, Jan Geuenich, Ulrike Hansper, Philipp Lampe, Julia Sauter

Funding: The summer school is supported by the Alexander von Humboldt Foundation in the framework of an Alexander von Humboldt Professorship endowed by the Federal Ministry of Education and Research.

Participants: The summer school is primarily intended for PhD students or young postdoctoral researchers.


We can find gentle algebras in many places in mathematics. The study of gentle algebras was initiated by Assem and Skowroński (who introduced them in order to study iterated tilted algebras of type A) and became an active area of research in representation theory in the recent years. Gentle algebras form an interesting class of examples because of the simple combinatorial definition and because of many connections to other classes of algebras such as string algebras, biserial algebras, special biserial algebras, tame algebras, Gorenstein algebras, Koszul algebras, Brauer graph algebras, and surface algebras.

Program of the summer school

Most participants gave a 60 minute talk on a specific topic. In addition there was a series of three talks given by our invited speaker Prof. Christof Geiß. More information can be found here:

Jan Geuenich has Live TeXed notes of the talks:

In the afternoon of Wednesday the 16th of August we made an excursion in the area around Bad Driburg.


Participants of the summer school on gentle algebras

Location and Travel

The summer school takes place at the Hotel Waldcafé Jäger, Waldstraße 1, 33014 Bad Driburg. The hotel is in walking distance from the train station of Bad Driburg.

There are regional trains to Bad Driburg from Paderborn and Altenbeken. When coming from the general direction of Düsseldorf one can change trains in Hamm (Westf) to get to either of those train stations. There are also trains from Bielefeld that stop in Altenbeken or Paderborn. Further information can be found on the homepage of Deutsche Bahn. The closest airports are in Paderborn-Lippstadt, Dortmund, Hannover, Düsseldorf and Frankfurt.

The summer school starts on Monday at about noon and ends on Friday at about noon to allow for time to travel. However participants are welcome to arrive on Sunday and/or to leave on Saturday in case that is more convenient.

The seminar room in the hotel is equipped with a reasonably sized whiteboard, a video projector and an overhead projector. Participants will be accommodated in double rooms.

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Please contact the organisers for any questions concerning the summer school.

Play with Gentle Algebras

Jan Geuenich has made an applet for string algebras. It allows the user to draw a quiver with relations and tells whether the associated algebra is gentle. If it gives a string algebra the applet lists many properties of the corresponding algebra.