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Ci-dessous, les différences entre deux révisions de la page.
| Les deux révisions précédentesRévision précédenteProchaine révision | Révision précédente | ||
| start [2024/11/18 15:51] – [Seminars and conferences] g.m | start [2025/02/18 14:56] (Version actuelle) – [Seminars and conferences] g.m | ||
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| Johannes Josi (February 2018). | Johannes Josi (February 2018). | ||
| - | Current members: Thomas Blomme, Francesca Carocci, Aloïs Demory, Gurvan | + | Current members: Thomas Blomme, Francesca Carocci, Aloïs Demory, Gurvan |
| Alumni: Ivan Bazhov, Johan Bjorklund, Rémi Crétois, Weronika Czerniawska, | Alumni: Ivan Bazhov, Johan Bjorklund, Rémi Crétois, Weronika Czerniawska, | ||
| Ligne 28: | Ligne 28: | ||
| ====== Seminars and conferences ====== | ====== Seminars and conferences ====== | ||
| ---- | ---- | ||
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| + | Joé Brendel (ETHZ), Friday, Feb 21, 15h15, room 6-13 (Seminaire " | ||
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| + | "Split tori in S^2 x S^2, billiards and ball-embeddability" | ||
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| + | Abstract: In this talk we will discuss the symplectic classification of Lagrangian tori that split as circles in S^2 x S^2. As it turns out, this classification is equivalent to playing mathematical billiards on a rectangular table. This has many interesting applications, | ||
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| + | Gurvan ²Ñé±¹±ð±ô (UNIGE), Wednesday, Feb 19, 14h00, room 1-07 (Seminaire " | ||
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| + | "Floor diagrams and some tropical invariants in positive genus" | ||
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| + | Abstract : Göttche-Schroeter invariants are a rational tropical refined invariant, i.e. a polynomial counting genus 0 curves on toric surfaces, that can be computed with a floor diagrams approach. In this talk I will explain that this approach extends in any genus. This gives new invariants, related to ones simultaneously defined by Shustin and Sinichkin. I will then say few words on a quadratically enriched (and not refined !) version of this extension. | ||
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| + | Uriel Sinichkin (Tel-Aviv), Wednesday, Feb 5, 14h00, room 1-07 + Zoom (Seminaire " | ||
| + | |||
| + | " | ||
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| + | Abstract: In this talk I will present a generalization of Goettche-Schroeter and Schroeter-Shustin refined counts of tropical curves that splits to a product of terms on small fragments of the curves. This count is invariant in each of the following situations: either genus at most one, or a single contact element, or point conditions in Mikhalkin position. I will compare our results to ²Ñé±¹±ð±ô’s floor diagram approach, and discuss the specialization of the count at q=1, which recovers certain characteristic numbers. | ||
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| + | Thomas Blomme (Neuchâtel), | ||
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| + | "Une preuve courte d’une formule de revêtement multiple" | ||
| + | |||
| + | Abstract: Enumérer les courbes de genre g passant par g points dans une surface abélienne est un problème naturel, et d’une difficulté surprenamment inégale en fonction du degré des courbes étudiées. Pour les degrés « primitifs », il est aisé d’obtenir une formule close par une résolution simple et explicite. Pour les classes « divisibles », une telle résolution est en revanche assez fastidieuse et souvent hors de portée. Pour autant, les invariants de ces dernières s’expriment aisément en fonction des invariants primitifs au travers de la formule de revêtement multiple, conjecturée par G. Oberdieck. Dans cet exposé, on va montrer comment la géométrie tropicale permet de prouver cette formule en esquivant toute forme concrète d’énumération. | ||
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| + | Ajith Urundolil-Kumaran (Cambridge), | ||
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| + | " | ||
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| + | Abstract: The mirror algebras constructed in the Gross-Siebert program come with a natural trace pairing. The Frobenius conjecture gives an enumerative interpretation for this pairing. In the Log Calabi-Yau surface case there exists a deformation quantization of the mirror algebra. We prove a quantum version of the Frobenius conjecture by interpreting it as a refined tropical correspondence theorem. This is joint work with Patrick Kennedy-Hunt and Qaasim Shafi. | ||
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| + | Marvin HAHN (Dublin), Wednesday, Dec 4, 14h00, room 06-13 (Seminaire " | ||
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| + | "A tropical twist on Hurwitz numbers" | ||
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| + | Hurwitz numbers count branched morphisms between Riemann surfaces with fixed numerical data. While a classical invariant, having been introduced in the 19th century, Hurwitz numbers are an active topic of study, among others due to their interplay with Gromov-Witten theory and their role in mirror symmetry. In recent work of Chapuy and Dołęga a non-orientable generalisation of Hurwitz numbers was introduced, so-called b-Hurwitz numbers. These invariants are a weighted enumeration of maps between non-orientable surfaces weighted by a power of a parameter b. This parameter should be viewed as measuring the non-orientability of the involved covers. For b=0, one recovers classical Hurwitz numbers, while b=1 represents a non-weighted count of non-orientable maps yielding so-called twisted Hurwitz numbers. In this talk, we derive a combinatorial model of twisted Hurwitz numbers via tropical geometry and employ it to derive a wide array of new structural properties. This talk is based on joint work with Hannah Markwig. | ||
| + | |||
| Aloïs DEMORY (Genève), Wednesday, Nov 20, 14h00, room 06-13 (Seminaire " | Aloïs DEMORY (Genève), Wednesday, Nov 20, 14h00, room 06-13 (Seminaire " | ||
| Ligne 37: | Ligne 78: | ||
| The very specific topological properties of the hypersurfaces produced using this method are quite well studied in the case of hypersurfaces in smooth toric varieties. We present an ongoing attempt to extend some of these properties to primitive surfaces in arbitrary 3-dimensional toric varieties. As a consequence, | The very specific topological properties of the hypersurfaces produced using this method are quite well studied in the case of hypersurfaces in smooth toric varieties. We present an ongoing attempt to extend some of these properties to primitive surfaces in arbitrary 3-dimensional toric varieties. As a consequence, | ||
| - | Friday, | + | |
| - | Seminaire | + | Ìý |
| + | " | ||
| + | Ìý | ||
| + | Abstract. I will review how to construct holomorphically symplectic manifolds, there are four series of hyperkahler ones, one non-Kahler (BG-manifolds) and some singular ones known. I will talk on ideas how to bound the Betti numbers of holomorphic symplectic manifolds. And explain on the connection to some other conjectures like Nagai’s conjecture and SYZ conjecture.Ìý | ||
| + | Ìý | ||
| + | | ||
| + | Ìý | ||
| + | Vladimir Fock (Strasbourg)Ìý | ||
| + | Ìý | ||
| + | "Goncharov-Kenyon integrable systems and plane curves"Ìý | ||
| + | Ìý | ||
| + | Goncharov-Kenyon constructed integrable system starting form any NewtonÌý | ||
| + | polygon which generalize plenty of known integrable systems. The phaseÌý | ||
| + | space of such system is the space of plane curves provided with a lineÌý | ||
| + | bundle. On the other hand the same space admit a description as aÌý | ||
| + | cluster variety and thus can be parameterized by algebraic tori. The aimÌý | ||
| + | of the talk is to describe these two points of view on the integrableÌý | ||
| + | system as well as discuss some other geometric interpretations of them.Ìý | ||
| + | Ìý | ||
| + | Ìý | ||
| + | Ìý | ||
| + | Ìý | ||
| + | Friday, Oct 18, 14h, 06-13, Stepan Orevkov (Toulouse) | ||
| "An algebraic curve with small boundary components in the 4-ball" | "An algebraic curve with small boundary components in the 4-ball" | ||
| Ligne 56: | Ligne 119: | ||
| - | Monday, Sep 23, 14h30, room 01-15 and Wednesday, Sep 25, 14h00, room 06-13, Rostislav MATVEEV (Leipzig). | + | Monday, Sep 23, 14h30, room 01-15 and Wednesday, Sep 25, 14h00, room 06-13, |
| + | Ìý | ||
| + | Rostislav MATVEEV (Leipzig).Ìý | ||
| " | " | ||
start.1731941493.txt.gz · Dernière modificationÌý: 2024/11/18 15:51 de g.m