## "Coarse Geometry". Hirzebruch colloquium talk by Walter Neumann

Coarse geometry can lead to useful classifications. For example, the word metric on a finitely presented group recognises (up to finite groups) if that group is the fundamental group of a 3-manifold and it carries a lot of information about the manifold. I will mainly talk about coarse geometry for complex surfaces, showing that bilipschitz geometry, which is purely topological and ignores any analytic structure, can recover the local analytic structure up to Zariski equisingularity. (Joint work with Anne Pichon).

## "Descartes, Euler, Gauss: From surfaces to integers". Hirzebruch lecture by Werner Ballmann on Monday, November 13

Geometric quantities of a surface, like distance, angle, or area, change when the surface is deformed. Euler discovered a quantity, the Euler characteristic, which remains unchanged. The formula of Gauss-Bonnet, a landmark result of mathematics, relates Euler characteristic with geometry. In the talk, I will present ideas of Descartes, Euler, and Gauss related to this formula.

## 3rd Japanese-German Number Theory Workshop, November 20 - 24, 2017

**3rd Japanese-German Number Theory Workshop**

**November 20 - 24, 2017**

Here you can find the official homepage

#### Organizers

- German Organizers : Jonas Kaszian (University of Cologne), Pieter Moree (MPIM)
- Japanese Organaizers : Hiroki Aoki (Tokyo University of Science), Koji Tasaka (MPIM/Aichi Prefectural University)

#### Speakers

Sho Takemori (MPIM)

Tomomi Ozawa (Univ. Paris 13)

Kenji Makiyama (Kyoto Sangyo Univ.)

Ren-he Su (Kyoto Univ.)

Nobuo Sato (Kyoto Univ.)

Hiraku Atobe (Tokyo Univ.)

Shingo Sugiyama (Kyushu Univ.)

Minoru Hirose (Kyushu Univ.)

Toshiki Matsusaka (Kyushu Univ.)

Shun'ichi Yokoyama (Kyushu Univ.)

Hiroshi Sakata (Waseda Univ Senior High School)

Hidetaka Kitayama (Wakayama Univ.)

Hiro-aki Narita (Kumamoto Univ.)

Takashi Nakamura (Tokyo Univ. of Science)

Hiroki Aoki (Tokyo Univ. of Science)

Claudia Alfes-Neumann (University of Cologne)

Jan Bruinier (TU Darmstadt)

Steffen Löbrich (University of Cologne)

Markus Schwagenscheidt (TU Darmstadt)

Annalena Wernz (RWTH Aachen)

## Workshop "Young Researchers in String Mathematics", November 27 - 30, 2017

**Workshop "Young Researchers in String Mathematics"**

**November 27 - 30, 2017**

## Conference on Arithmetic and Automorphic Forms on the occasion of Günter Harder's 80th birthday, March 12 - 14, 2018

**Conference on **

**Arithmetic and Automorphic Forms **

**on the occasion of Günter Harder's 80th birthday**

**March 12 - 14, 2018**

#### Scientific Committee

Werner Ballmann, Michael Rapoport, and Joachim Schwermer

#### Local Organizer

Werner Ballmann and Christian Blohmann

#### Speakers

Kai Behrend (U British Columbia)

Spencer Bloch (U Chicago)

Gaetan Chenevier (U Paris-Sud, Orsay)

Mark Goresky (IAS Princeton)

Tasho Kaletha (U Michigan)

Stephen S. Kudla (U Toronto)

Richard Pink (ETH Zürich)

Anantharam Raghuram (IISER Pune)

Andrei Rapinchuk (U Virginia)

Peter Scholze (U Bonn)

Carlos Simpson (U Nice)

Gerard van der Geer (U Amsterdam)