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Les deux révisions précédentesRévision précédenteProchaine révision | Révision précédenteProchaine révisionLes deux révisions suivantes | ||
start [2022/10/12 15:09] – kalinin0 | start [2024/02/12 13:39] – thomas2 | ||
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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: | ||
Ligne 16: | Ligne 16: | ||
[[fables|Séminaire " | [[fables|Séminaire " | ||
- | pre-2017 [[batelle|Battelle Seminar]] and | + | pre-2017 |
[[working|Tropical working group Seminar]]. | [[working|Tropical working group Seminar]]. | ||
Ligne 28: | Ligne 28: | ||
====== Seminars and conferences ====== | ====== Seminars and conferences ====== | ||
- | ---------------- | + | ---- |
- | Geneva-Neuchâtel Symplectic Geometry seminar | + | 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 | ||
+ | |||
+ | " | ||
+ | |||
+ | 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 | ||
+ | |||
+ | "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, | ||
+ | |||
+ | ---- | ||
+ | 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. | ||
+ | |||
+ | ---- | ||
- | **2022, October | + | Gurvan Mével (Université de Nantes), Wednesday, Oct 18, at 14h15, Salle 06-13 |
+ | “Universal polynomials for coefficients of tropical refined invariant in genus 0” | ||
- | Ilia Itenberg (Sorbonne) | + | In enumerative |
- | Real enumerative | + | |
- | Salle 6-13, 14h15 | + | |
- | **Abstract: | + | Tropical refined invariants are polynomials resulting of a weird way of counting curves, but linked with the previous enumerations. When the genus is fixed, Brugallé and Jaramillo-Puentes proved that some coefficients of these polynomials behave polynomially, |
- | The talk is devoted to several real and tropical enumerative problems. | ||
- | We suggest new invariants of the projective plane (and, more generally, of toric surfaces) | ||
- | that arise as results of an appropriate enumeration of real elliptic curves. | ||
- | These invariants admit a refinement (according to the quantum index) similar to the one introduced by Grigory Mikhalkin in the rational case. | ||
- | We discuss the combinatorics of tropical counterparts of the elliptic invariants under consideration and establish a tropical algorithm | ||
- | allowing one to compute them. | ||
- | This is a joint work with Eugenii Shustin. | ||
[[symplectic| seminar page]] | [[symplectic| seminar page]] | ||
Ligne 69: | Ligne 109: | ||
- | 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 : 2024/09/22 16:29 de thomas2