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start [2021/10/24 16:35] – kalinin0 | start [2024/03/12 13:12] – slavitya_gmail.com | ||
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- | PhD graduated: Kristin Shaw (December 2011), Lionel Lang (December 2014), [[http://mathcenter.spb.ru/nikaan/|Nikita Kalinin]] (December 2015), [[Mikhail Shkolnikov|Mikhail Shkolnikov]] (June 2017), | + | PhD graduated: Kristin Shaw (December 2011), Lionel Lang (December 2014), [[https://scholar.google.com/citations? |
Johannes Josi (February 2018). | Johannes Josi (February 2018). | ||
- | Current members: | + | Current members: Thomas Blomme, |
- | Alumni: Ivan Bazhov, Johan Bjorklund, Rémi Crétois, Yi-Ning Hsiao, Jens Forsgard, Maxim Karev, Ilya Karzhemanov, | + | Alumni: Ivan Bazhov, Johan Bjorklund, Rémi Crétois, Weronika Czerniawska, Yi-Ning Hsiao, Jens Forsgard, Maxim Karev, Ilya Karzhemanov, |
We organize several seminars: | We organize several seminars: | ||
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[[fables|Séminaire " | [[fables|Séminaire " | ||
- | pre-2017 [[batelle|Battelle Seminar]] and | + | pre-2017 |
[[working|Tropical working group Seminar]]. | [[working|Tropical working group Seminar]]. | ||
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====== Seminars and conferences ====== | ====== Seminars and conferences ====== | ||
+ | ---- | ||
- | | + | |
+ | |||
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+ | |||
+ | "Basic algebra and algebraic geometry special talk" | ||
+ | |||
+ | "Real plane sextic curves without real singular points" | ||
+ | |||
+ | We will start with a brief introduction to topology of real algebraic curves, | ||
+ | and then will discuss in more details the case of curves of degree 6 in the real projective plane. | ||
+ | We will prove that the equisingular deformation type of a simple real plane sextic curve | ||
+ | with smooth real part is determined by its real homological type, that is, the polarization, | ||
+ | and real structure recorded in the homology of the covering K3-surface (this is a joint work with Alex Degtyarev). | ||
+ | |||
+ | ---- | ||
+ | Alexander Bobenko (TU Berlin), Feb 16, 2024, at 14h30, Salle 01-05 | ||
+ | |||
+ | " | ||
+ | |||
+ | We develop a general approach to dimer models analogous to Krichever’s scheme in the theory of integrable systems. This leads to dimer models on doubly periodic bipartite graphs with quasiperiodic positive weights. | ||
+ | This generalization from Harnack curves to general M-curves leads to transparent algebro-geometric structures. In particular explicit formulas for the Ronkin function and surface tension as integrals of meromorphic differentials on M-curves are obtained. Based on Schottky uniformizations of Riemann surfaces we compute the weights and dimer configurations. The computational results are in complete agreement with the theoretical predictions. Also relation to discrete conformal mappings and to hyperbolic polyhedra is explained. This is a joint work with N. Bobenko and Yu. Suris. | ||
+ | |||
+ | |||
+ | ---- | ||
+ | Francesca Carocci (Genève), Dec 8, 14h30, Salle 06-13 | ||
+ | |||
+ | " | ||
+ | |||
+ | Maps to projective space are given by basepoint-free linear series, thus these are key to understanding the extrinsic geometry of algebraic curves. | ||
+ | How does a linear series degenerate when the underlying curve degenerates and becomes nodal? | ||
+ | Eisenbud and Harris gave a satisfactory answer to this question when the nodal curve is of compact type. Eisenbud-Harris' | ||
+ | I will report on a joint work in progress with Lucaq Battistella and Jonathan Wise, in which we review this question from a moduli-theoretic and logarithmic perspective. The logarithmic prospective helps understanding the rich polyhedral and combinatorial structures underlying degenerations of linear series. These are linked with matroids and Bruhat-Titts buildings. | ||
+ | |||
+ | ---- | ||
+ | Diego MATESSI (Milano), Dec 4, 15h, Salle 06-13 | ||
+ | |||
+ | " | ||
+ | |||
+ | I will present some work in progress jont with Arthur Renaudineau. | ||
+ | |||
+ | |||
+ | ---- | ||
+ | Thomas Blomme, université de Genève, Thursday, Nov 9, 16h15, Room 1-15. | ||
+ | |||
+ | " | ||
+ | |||
+ | Bielliptic surfaces were classified by Bagnera & de Francis more than a century ago. They form a family spread into seven subfamilies of the Kodaira-Enriques surface classification which have nearly trivial canonical class in the sense that it is non-zero, but torsion. Thus, the virtual dimension of the moduli space of curves only depends on the genus, and contrarily to abelian and K3 surfaces, it yields non-zero invariants. In this talk we'll focus on some techniques to compute GW invariants of these surfaces along with some regularity properties. | ||
+ | |||
+ | ---- | ||
+ | Antoine Toussaint, université de Genève, Monday, Oct 23, at 15h, Salle 06-13 | ||
| | ||
- | Nov 1, 16h15. Room 06-13 | + | "Real Structures of Phase Tropical Surfaces" |
- | + | ||
- | | + | Phase tropical surfaces can appear as a limit of a 1-parameter family of smooth complex algebraic surfaces. A phase tropical surface admits a stratified fibration over a smooth tropical surface. We study the real structures compatible with this fibration and give a description in terms of tropical cohomology. As an application, we deduce combinatorial criteria for the type of a real structure of a phase tropical surface. Time permitting, we will also discuss the connection with Renaudineau and Shaw's spectral sequence and Kalinin' |
- | + | ||
- | **Modularity proofs via fibered motives** | + | ---- |
+ | Ozgur CEYHAN (University of Luxembourg), | ||
+ | |||
+ | " | ||
+ | |||
+ | The backpropagation algorithm and its variations are the primary training method of multi-layered neural networks. The backpropagation is a recursive gradient descent technique that works on large matrices. | ||
+ | This talk explores backpropagation via tropical linear algebra and introduces multi-layered tropical neural networks as universal approximators. After giving a tropical reformulation of the backpropagation algorithm, we verify the algorithmic complexity is substantially lower than the usual backpropagation as the tropical arithmetic is free of the complexity of usual multiplication. | ||
+ | |||
+ | ---- | ||
+ | |||
+ | | ||
+ | |||
+ | “Universal polynomials for coefficients of tropical refined invariant in genus 0” | ||
- | This is a report on joint work with Don Zagier, and joint work | + | In enumerative geometry, some numbers of curves on surfaces are known to behave polynomially when the cogenus is fixed and the linear system varies, whereas it grows more than exponentially fast when the genus is fixed. In the first case, Göttsche' |
- | in progress with Kilian Bönisch and Albrecht Klemm. | + | |
- | The rigid Calabi-Yau threefolds that appear as conifold fibers | + | Tropical refined invariants |
- | in the hypergeometric Landau-Ginzburg models of Fano | + | |
- | complete intersection fourfolds in [weighted] projective spaces | + | |
- | are expected to be modular, but what is lacking is the | + | |
- | construction of actual correspondences | + | |
- | threefolds. I will explain how the technique | + | |
- | can be used to provide `opportunistic' | + | |
- | proofs | + | |
- | [[fables|Séminaire " | ||
+ | [[symplectic| seminar page]] | ||
====== Geneva-Neuchâtel Symplectic Geometry Seminar ====== | ====== Geneva-Neuchâtel Symplectic Geometry Seminar ====== | ||
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- | If you want to register, say me (Misha Shkolnikov). | + | You should be approved user to edit pages. |
You can write here something. (Create a small web page about you, write about you interests, explain tropical philosophy of our group, upload articles etc). | You can write here something. (Create a small web page about you, write about you interests, explain tropical philosophy of our group, upload articles etc). | ||
start.txt · Dernière modification : 2024/03/12 13:13 de slavitya_gmail.com