Joint Seminar - 2013-2023
Joint Seminar on Complex Algebraic Geometry and Complex Analysis (Bochum - Essen - Köln - Münster - Wuppertal)
Photo by Max Greve and Timo Bobert
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
At the next meeting, we will CELEBRATE that the seminar has been running continuously for 10 YEARS now !
DATE AND PLACE
The next meeting will take place on Friday, April 28th, 2023 at Ruhr-Universität Bochum (on-site).
- Hans-Joachim Hein (Münster) : A gluing construction for surfaces with hyperbolic cusps
We will describe an example of a degeneration of sextics in P^3 with only ordinary triple point singularities on its central fiber. Then we will show how the unique negative Kähler-Einstein metrics on the smooth fibers, which exist by the Aubin-Yau theorem, disintegrate into three distinct geometric pieces on approach to the central fiber: (1) Kobayashi's complete Kähler-Einstein metric on the complement of the triple points, (2) long thin neck regions, and (3) Tian-Yau's complete Ricci-flat Kähler metrics in small neighborhoods of the vanishing cycles. All of the necessary background will be explained in the talk. Joint work with Xin Fu and Xumin Jiang.
- Silvia Sabatini (Cologne): Topological properties of (tall) monotone complexity one
In symplectic geometry it is often the case that compact symplectic manifolds with large group symmetries admit indeed a Kähler structure. For instance, if the manifold is of dimension 2n and it is acted on effectively by a compact torus of dimension n in a Hamiltonian way (namely, there exists a moment map which describes the action), then it is well-known that there exists an invariant Kähler structure. These spaces are called symplectic toric manifolds or also complexity-zero spaces, where the complexity is given by n minus the dimension of the torus. In this talk I will explain how there is some evidence that a similar statement holds true when the complexity is one and the manifold is monotone (the latter being the symplectic analog of the Fano condition in algebraic geometry), namely, that every monotone complexity-one space is simply connected and has Todd genus one, properties which are also enjoyed by Fano varieties. These results are largely inspired by the Fine-Panov conjecture and are in collaboration with Daniele Sepe. Moreover, in ongoing work with Isabelle Charton and Daniele Sepe, we completely classify monotone complexity one space that are “tall” (no reduced space is a point), proving as a byproduct that the torus action extends to a full toric action and that each of these spaces admits a Kähler structure.
- Richard Wentworth (Maryland / MPI Bonn): A Donaldson-Uhlenbeck-Yau theorem for normal projective varieties
The correspondence between polystable reflexive sheaves on compact Kaehler manifolds and the existence of suitably singular Hermitian-Einstein metrics can be extended to normal projective varieties that are smooth in codimension two. A particular application is a characterization of those sheaves which saturate the Bogomolov-Gieseker inequality. This talk will present some of the key details of this result, which is joint work with Xuemiao Chen.
11:00 - 12:00 Sabatini
afterwards Lunch break
14:00 - 15:00 Hein
afterwards Coffee break
16:00 - 17:00 Wentworth
The talks will take place in Room IA 01/473 at the Ruhr-Universität Bochum. A campus map indicating the location of the Buliding can be found here.
stephanie [dot] cupit [at] ruhr-uni-bochum [dot] de
daniel [dot] greb [at] uni-due [dot] de
ursula [dot] ludwig [at] uni-muenster [dot] de
Universität zu Köln
gmarines [at] math [dot] uni-koeln [dot] de
Bergische Universität Wuppertal
jean [dot] ruppenthal [at] math [dot] uni-wuppertal [dot]de
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