Joint Seminar on Complex Algebraic Geometry and Complex Analysis
(Bochum - Essen - Köln - Wuppertal)

Photo by Max Greve and Timo Bobert

The Seminar

The "Joint Seminar on Complex Algebraic Geometry and Complex Analysis" is a research seminar, organised by the algebraic and complex geometry research groups in Bochum, Essen, Cologne, and Wuppertal. The seminar meets roughly twice per semester for a full day in Bochum, Essen, Cologne, or Wuppertal. There are three talks per meeting, both by invited guests and by speakers from the organising universities. We aim to leave ample room for discussions.

The talks are open for everyone. Contact one of the organisers if you are interested in attending the meeting. We have some funds that might help to support travel for some junior participants.

Meetings of the seminar are partially supported by

  • SFB/TR 45 "Periods, moduli spaces and arithmetic of algebraic varieties"
  • SFB/TR 191 "Symplectic structures in geometry, algebra and dynamics"

Next Meeting


The next meeting will take place on Friday, July 5th, 2019 in Cologne.


  • Tien-Cuong Dinh (Singapore / Cologne): Unique Ergodicity for foliations on compact Kähler surfaces

    Let F be a holomorphic foliation by Riemann surfaces on a compact Kaehler surface. Assume it is generic in the sense that all the singularities are hyperbolic and that the foliation admits no directed positive closed (1,1)-current. Then there exists a unique (up to a multiplicative constant) positive ddc-closed (1,1)-current directed by F. This is a very strong ergodic property of F. Our proof uses an extension of the theory of densities to a class of non-ddc-closed currents. A complete description of the cone of directed positive ddc-closed (1,1)-currents is also given when F admits directed positive closed currents. The talk is based on a recent joint work with Viet-Anh Nguyen and Nessim Sibony.

  • Xiaonan Ma (Paris VII / Cologne): Quantization commutes with reduction, a survey

    We will review different versions of 'quantization commutes with reduction’ from Kahler to symplectic case. We will also consider the non-compact symplectic situation and the most recent result on CR manifolds.

  • Nessim Sibony (Orsay): Equidistribution in Nevanlinna's Theory

    The classical Nevanlinna theory is developed for maps from the complex plane with values in a projective variety. Motivated by the theory of singular foliations by Riemann surfaces and their dynamics, I will study the case where the source space is hyperbolic. It could be the disc or the unit ball. I will give applications to foliations by Riemann Surfaces.


10:30 - 11:30 Sibony

11:45 - 12:45 Ma

12:45 - 14:30 Lunch break

14:30 - 15:30 Dinh


Universität zu Köln
Mathematisches Institut
Weyertal 86-90

All talks will take place in Room 204 (Seminar room 2).

How to find the lecture hall: see the following map.


Kevin Fritsch
Ruhr-Universität Bochum
kevin [dot] fritsch [at] rub [dot] de

Daniel Greb
Universität Duisburg-Essen
daniel [dot] greb [at] uni-due [dot] de

George Marinescu
Universität zu Köln
gmarines [at] math [dot] uni-koeln [dot] de

Jean Ruppenthal
Bergische Universität Wuppertal
jean [dot] ruppenthal [at] math [dot] uni-wuppertal [dot]de

Past Meetings

26.4.2013, Bochum: Tim Kirschner, Christian Miebach, Henrik Seppänen

28.6.2013, Wuppertal: Rafael Andrist, Immanuel Stampfli, Matei Toma

22.11.2013, Bochum: Sébastien Boucksom, Egmont Porten, Sönke Rollenske

24.1.2014, Wuppertal: Clemens Jörder, Helge Ruddat, Jörg Winkelmann

16.5.2014, Bochum: Alberto Abbondandolo, Judith Brinkschulte, Julius Ross

20.6.2014, Wuppertal: Julie Déserti, Slawomir Dinew, Slawomir Rams

24.10.2014, Bochum: Henri Guenancia, Shulim Kaliman, Adriano Tomassini

15.12.2014, Wuppertal: Richard Lärkäng, Christian Miebach, Marco Spinaci

7.5.2015, Essen: Brent Doran, Erwan Rousseau, Emanuel Scheidegger

15.6.2015, Bochum: Roya Beheshti, Daniel Greb, Hossein Raufi

27.11.2015, Wuppertal: Francesco Bei, Kai Cieliebak, Tyson Ritter

1.2.2016, Essen: Ursula Ludwig, George Marinescu, Wenhao Ou

25.4.2016, Wuppertal: Gian Maria Dall’Ara, Christian Lehn, Luca Tasin

26.6.2016, Cologne: Chin-Yu Hsiao, Stefan Nemirovski, Nikhil Savale

25.11.2016, Bochum: Ana-Maria Brecan, Antonio di Scala, Dan Popovici

27.1.2017, Essen: Tim Kirschner, Viêt Anh Nguyên, Stefan Schreieder

21.4.2017, Wuppertal: Vicente Cortés, Philipp Naumann, Markus Reineke

7.7.2017, Cologne: Roger Bielawski, Dan Coman, Martin Schwald

3.11.2017, Bochum: Junyan Cao, Sönke Rollenske, Robert Szöke

1.2.2018, Essen: Gilberto Bini, Ruadhaí Dervan, Hendrik Herrmann

27.4.2018, Wuppertal: Hugues Auvray, Bernd Stratmann, Michael Lennox Wong

6.7.2018, Cologne: Turgay Bayraktar, Jarek Buczynski, Andrew Dancer

23.11.2018, Bochum: Ben Anthes, Kevin Fritsch, Ariyan Javanpeykar

18.1.2019, Essen: André Belotto, Andreas Höring, Valdemar Tsanov

12.4.2019, Wuppertal: Ya Deng, Christian Miebach, Duc Viet Vu