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Hidetoshi Masai <br>
Hidetoshi Masai <br>
Jon McCammond <br>
Jon McCammond <br>
Felix Nötzel <br>
Dmitri Panov <br>
Dmitri Panov <br>
Tomasz Prytuła <br>
Tomasz Prytuła <br>

Revision as of 09:06, 13 September 2017

Workshop: Non-Positively Curved Groups and Spaces

The workshop will take place during the week September 18-22, 2017 at the Faculty of Mathematics of Universität Regensburg.

  • Abstracts of mini-courses and talks: pdf-file.
  • The poster is available here: link.

Please note that in the week following the Workshop, the Conference: Manifolds and Groups takes place at the same location!

Non-Positively Curved Groups and Spaces is the third in a series of workshops organized in Regensburg. The second was on Large Scale Dimensions and the first was on Cohomology and Large Scale Geometry.


Registration is now closed. If you want to attend, please send an email to one of the organizers.

Mini-courses by

  • Topology of Open Non-Positively Curved Manifolds
    by Igor Belegradek (Georgia Tech)

The mini-course will give a panorama of topological properties of complete open manifolds of nonnegative sectional curvature. The exposition will be loosely based the survey in https://arxiv.org/abs/1306.1256 except that there will be less emphasis on the speaker's work.

  • Braid Groups and Non-Positive Curvature
    by Jon McCammond (UC Santa Barbara)

It has long been conjectured that the braid groups are nonpositively curved in the sense that they have a geometric action on some complete CAT(0) space, and a promising candidate has been known for some time. For each positive integer n, a contractible n-dimensional simplicial complex with a free and cocompact n-string braid group action was constructed by Tom Brady in 2001 and a piecewise-euclidean metric was added to these complexes by Brady and myself shortly afterwards. I call this the dual braid n-complex with the orthoscheme metric. These particular complexes with this particular metric were conjectured to be CAT(0) spaces for every n and this conjecture has been established when n is very small. During the three lectures of the mini-course I will describe these complexes and metrics in detail, report on some recent results related to the main conjecture, and discuss some connections to other parts of mathematics. The recent results are joint work Michael Dougherty and Stefan Witzel.

The titles of the three lectures are

1. Graphical braids and orthoschemes
2. Boundary braids and curvature
3. The braid arrangement and polynomials

Acylindrically hyperbolic groups form a very large and rather diverse class of groups that includes non-elementary (relatively) hyperbolic groups, mapping class groups, outer automorphisms of free groups, CAT(0) groups with rank-one elements, and many, many others. Acylindrically hyperbolic groups turn out to share many of the "largeness" properties of non-abelian free groups, including having uncountably many quotients and infinite dimensional bounded cohomology.

In the mini-course, I will explain the definition, which involves the existence of an action with certain properties on a hyperbolic space, and I will then explain the idea behind the construction of such hyperbolic space in some of the examples. We will then discuss aspects of the geometry of acylindrically hyperbolic groups.

Talks by

Grigori Avramidi (Universität Münster)
Sabine Braun (Karlsruher Institut für Technologie)
Matthew Cordes (Technion)
Tomohiro Fukaya (Tokyo Metropolitan University)
Ilya Gekhtman (Yale University)
Camille Horbez (Université Paris-Sud)
Thilo Kuessner (Universität Augsburg)
Dmitri Panov (King's College London)
Tomasz Prytuła (University of Southampton)
Jacek Świątkowski (Uniwersytet Wrocławski)


The talks will be in the lecture hall H51, which is close to the Biology part of the campus; see the University Map. Registration and coffee breaks will be nearby.

More information about the poster session will be announced soon.

  • Abstracts of mini-courses and talks: pdf-file.
Monday Tuesday Wednesday Thursday Friday
08:30 - 09:00
09:00 - 10:15
Belegradek I
09:00 - 10:15
McCammond II
09:00 - 10:15
Belegradek III
09:00 - 10:15
Sisto II
09:00 - 10:15
Sisto III
10:15 - 10:45
10:45 - 12:00
McCammond I
10:45 - 12:00
Belegradek II
10:45 - 12:00
Sisto I
10:45 - 12:00
McCammond III
10:45 - 11:45
14:00 - 15:00
14:00 - 15:00

Guided tour (see information below)
14:00 - 15:00
15:30 - 16:30
15:30 - 16:30
15:30 - 16:30
17:00 - 18:00
17:00 - 18:00
17:00 - 18:00
18:30 - ∞
Poster session and pizza in M201 (math. faculty)
19:00 - ∞
Conference dinner in Brauhaus am Schloss

Guided Tour

We will visit the Old Town Hall (Reichstagsmuseum). The tour is entirely inside the building, thus it will take place regardless of the weather. We are going to meet at 17:25 in front of the information office (or inside in case of rain) at Rathausplatz (see the map).

Registered participants

Bernd Ammann
Kyle Austin
Grigori Avramidi
Malkhaz Bakuradze
Igor Belegradek
Federico Berlai
Sabine Braun
Matthew Cordes
Diego Corro Tapia
Alexander Engel
Daniel Fauser
Elia Fioravanti
Tomohiro Fukaya
Kei Funano
Ana Karla García Pérez
Ilya Gekhtman
Julia Heller
Nicolas Heuer
Camille Horbez
Annette Karrer
Motoko Kato
Jan-Bernhard Kordaß
Thilo Kuessner
Eon-Kyung Lee
Sang-Jin Lee
Robin Loose
Michał Marcinkowski
Hidetoshi Masai
Jon McCammond
Felix Nötzel
Dmitri Panov
Tomasz Prytuła
Janusz Przewocki
Benedikt von Seelstrang
Nasrin Sadegh Zadeh
Michael Schrödl
Alessandro Sisto
Robin Sroka
Jacek Świątkowski
Daniel Woodhouse
Alexander Zakharov
Pascal Zschumme

Practical Information

  • TRAVEL: In order to reach the university kindly follow the instructions here.
  • INTERNET: Access to eduroam is available throughout the mathematics building.

MAP: Points of Interest.

University Map.

PUBLIC TRANSIT: Local bus system and route map.

There are many useful buses typically, but the 6 will suffice for getting to and from the city center and the conference room (nearest stops are either 'An der Kreuzbreite' or 'Neuprull'). There should be signs pointing to the lecture hall.

One can also walk from the 'Universitat' bus stop, which is better served by the bus system. The 6, 11, C6, and C11 buses all travel between the HBF (central station) and the Universitat bus stop. The above maps may prove helpful.

You can pay for a bus ride on entering the bus or purchase a strip of tickets from one of the ticket machines. A strip of tickets costs 9.00 euros and it allows five bus rides.

ACCOMMODATION: We have reserved a block of hotel rooms at the Hotel Apollo. Participants will need to book and pay for their own accommodation, although the Hotel Apollo should be able to arrange shared rooms (double / twin) for participants with limited financial support (all pre-PhD participants requesting financial support should request a shared room). Please refer to PROMOTION CODE "SFB 0917" when making a reservation!

Regensburg is a tourist destination and we encourage guests to book their rooms as early as possible. Here is a list of hotels in the area:

1. Hotel Kaiserhof am Dom (In the city center, must take a bus to the University.)

2. Hotel Muenchner Hof (In the city center, must take a bus to the University.)

3. Hotel Apollo (Near the conference, but limited eating options.)

4. Hotel Jakob (In the center, must take a bus to the University.)

5. Hotel Central (In the city center, must take a bus to the University.)

One can also check the standard alternatives:

1. Hotels.com

2. Airbnb

Please use this Google sheet to find a roommate.