Joint Seminar


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

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



Next Meeting


DATE AND PLACE


The next meeting will take place on Friday, July 12th, 2024 at Ruhr-Universität Bochum.


TALKS


  • Antoine Boivin (Angers) : Compactification of Moduli Spaces of Quantum Toric Stacks

    Abstract:
    A toric variety is a complex variety which is completely described by the combinatorial data of a fan of strongly convex rational (with respect to a lattice) cones. Due to this rationality condition, toric varieties are (equivariantly) rigid since if we deform a lattice, it can become dense. A solution to this problem is to consider a stacky generalization of toric varieties where the "lattice" is, in fact, a finitely generated subgroup of $\mathbb{R}^d$ (in the simplicial case as introduced by L. Katzarkov, E. Lupercio, L. Meersseman and A. Verjovsky). The goal of this talk is to explain the moduli spaces of quantum toric stacks and their compactification.


  • Bingxiao Liu (Cologne): Toeplitz-Fubini-Study forms and lowest eigenvalues of Toeplitz operators

    Abstract:
    For a complex manifold equipped with a positive line bundle, Tian's approximation theorem states that, by considering the high tensor powers of this line bundle, the sequence of the induced Fubini-Study metrics via the Kodaira maps converges to the first Chern form of the line bundle. In this talk, we study the corresponding extensions of Tian's approximation theorem by combining the Kodaira maps with the Berezin-Toeplitz quantization, in particular with the twisting by the Toeplitz operators. Moreover, if the manifold is assumed to be compact, such a question is closely related to the study of the lowest eigenvalues of the Toeplitz operators with a given symbol. Finally, some estimates and further questions concerning the lowest eigenvalues of Toeplitz operators will be discussed.


  • Jörg Schürmann (Münster): Equivariant toric geometry and Euler-Maclaurin formulae

    Abstract:
    Using equivariant Todd (resp. Hirzebruch) classes of toric varieties, we translate the equivariant Hirzebruch-Riemann-Roch theorem for simplicial toric varieties into various (weighted) Euler-MacLaurin type formulae for simple lattice polytopes. This is joint work with S. Cappell, L. Maxim and J. Shaneson, see the papers arXiv:2403.19715 (short version) and arXiv:2303.16785 (long version).



SCHEDULE


10:30 - 11:30 Liu

11:45- 12:45 Boivin

afterwards Lunch break

14:30 - 15:30 Schürmann


VENUE


Talks will take place in Seminar Room ID 03/401. A campus map can be found here.





Organisers


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

25.11.2022, Wuppertal: Masanori Adachi, Laurentiu Maxim, Sara Torelli

20.1.2023, Cologne: Fabrizio Bianchi, Tobias Harz, Susanna Zimmermann

28.4.2023, Bochum: Hans-Joachim Hein, Silvia Sabatini, Richard Wentworth; 10 year celebration

7.7.2023, Essen: Ravjot Kohli, Thomas Kurbach, Niklas Müller

27.10.2023, Münster: Stefan Nemirovski, Shu Shen, Carolina Tamborini

19.2.2024, Wuppertal: Bo Berndtsson, Ana Botero, Jörg Winkelmann

26.4.2024, Cologne: Cécile Gachet, Christian Lehn, Johannes Scheffler