Joint Seminar on Complex Algebraic Geometry and Complex Analysis
(Bochum - Essen - Köln - Münster - 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, Münster, and Wuppertal. The seminar meets roughly twice per semester for a full day at one of the participating departments. 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 the DFG via

  • GRK 2553 "Symmetries and Classifying Spaces - analytic, arithmetic, and derived" (Essen)
  • SFB/TR 191 "Symplectic structures in geometry, algebra and dynamics" (Bochum-Cologne-Heidelberg)
  • ANR-DFG-Projekt QuaSiDy - "Quantization, Singularities, and Holomorphic Dynamics"

Next Meeting


The next meeting will take place on Friday, November 25th, 2022 at Bergische Universität Wuppertal (on-site).


  • Masanori Adachi (Shizuoka/Cologne): A residue formula for meromorphic connections and applications to stable sets of foliations

    We discuss a proof for Brunella’s conjecture: a codimension one holomorphic foliation on a compact complex manifold of dimension > 2 has no exceptional minimal set if its normal bundle is ample. The main idea is the localization of the first Chern class of the normal bundle of the foliation via a holomorphic connection. Although this localization was done via that of the first Atiyah class in our previous proof, we shall explain that this can be shown more directly by a residue formula. This talk is based on joint works with S. Biard and J. Brinkschulte.

  • Laurentiu Maxim (Madison/MPI Bonn): On the topology of aspherical complex projective manifolds and related questions

    I will report on recent progress on various open problems involving aspherical complex projective manifolds, including the Singer-Hopf conjecture and the Bobadilla-Kollar conjecture. The first part of the talk will be very informal, stating the main problems, historical developments, and some recent results. In the second part I will introduce the main technical tools and sketch proofs of some of the recent results.

  • Sara Torelli (Hannover): Holomorphic one forms on moduli of curves

    The moduli space $\mathcal{M}_g$ of smooth projective curves of genus $g$ is a quasi-projective variety, singular on loci of dimension at most $2g-1$. Let $\mathcal{M}^0_g$ denote its smooth locus. Not much is known about the cohomology $H^i(\mathcal{M}^0_g, \mathbb{C})$ and even less about the spaces of holomorphic forms $H^i(\Omega^j_{\mathcal{M}^0_g})$. Notice that $\mathcal{M}_g$ is not compact, so in particular it doesn't carry a Hodge decomposition and thus $H^i(\Omega^j_{\mathcal{M}^0_g})$ can't be recovered from $H^i(\mathcal{M}^0_g, \mathbb{C})$ just using Hodge theory. In the talk I will present the result for $i=1,j=0$, namely that $\mathcal{M}^0_g$ does not admit holomorphic 1-forms. The work is joint with F.F. Favale and G.P.Pirola.


10:30 - 11:30 Adachi

11:45 - 12:45 Maxim

afterwards Lunch break

14:30 - 15:30 Torelli


Morning talks will take place in Hörsaal 10, afternoon talks in Hörsaal 8. A campus map indication the location of the lecture halls can be found here.


Stéphanie Cupit-Foutou
Ruhr-Universität Bochum
stephanie [dot] cupit [at] ruhr-uni-bochum [dot] de

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

Ursula Ludwig
WWU Münster
ursula [dot] ludwig [at] uni-muenster [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

5.7.2019, Cologne: Tien-Cuong Dinh, Xiaonan Ma, Nessim Sibony

21.11.2019, Bochum: Patrick Graf, Ulrike Rieß, Jonas Stelzig

16.1.2020, Essen: Anda Degeratu, Takeo Ohsawa, Mihai Paun

14.5.2020, Wuppertal (via ZOOM): Lynn Heller, Simone Marchesi, Jan Swoboda

16.7.2020, Cologne (via ZOOM): Shin-ichi Matsumura, Sönke Rollenske, Lars Martin Sektnan

17.11.2020, Bochum (via ZOOM): Rafael Andrist, Nicholas Buchdahl, Eleonora di Nezza

29.1.2021, Essen (via ZOOM): Robert Berman, Simone Diverio, Ilaria Mondello

7.5.2021, Wuppertal (via ZOOM): Siarhei Finski, Laszlo Lempert, Katharina Neusser

18.6.2021, Cologne (via ZOOM): Gordon Heier, Louis Ioos, Ursula Ludwig

26.11.2021, Bochum: Nikhil Savale, Martin Schwald, Jörg Winkelmann

11.03.2022, Essen: Narasimha Chary Bonala, Matteo Costantini, Josias Reppekus

27.05.2022, Münster: Markus Banagl, Francesco Bei, Nicolina Istrati

20.06.2022, Essen: Workshop organised by JS organisers