AV��Ƶ

�پ��ڴ�é��Գ��

Ci-dessous, les différences entre deux révisions de la page.

--- symplectic [2024/12/02 11:32] – g.m
+++ symplectic [2025/05/04 18:57] (Version actuelle) – g.m
@@ Ligne 1: / Ligne 1: @@
 ===== GeNeSys: Geneva-Neuchâtel Symplectic geometry seminar =====
+**2025, May 6, Tuesday, Université de Neuchâtel**
+  Marco Golla (Université de Nantes, CNRS)
+h00, Salle B217
+  Alexander polynomials and symplectic curves in CP^2
+Libgober defined the Alexander polynomial of a (complex) plane projective curve and showed that it detects some Zariski pairs ofcurves: these are curves with the same degree and the same singularities but with non-homeomorphic complements. He also proved that the Alexander polynomial of a curve divides the Alexander polynomial of its link at infinity and the product of Alexander polynomials of the links of its singularities. We extend Libgober's definition to the symplectic case and prove that the divisibility relations also hold in this context. This is joint work with Hanine Awada.
+  Conan Leung (The Chinese AV����Ƶ of Hong Kong)
+h30, Salle B217
+d Mirror Symmetry is 2d Mirror Symmetry
+We introduce an approach to study 3d mirror symmetry via 2d mirror symmetry. The main observations are: (1) 3d brane transforms are given by SYZ-type transforms; (2) the exchange of symplectic and complex structures in 2d mirror symmetry induces the exchange of Kähler and equivariant parameters in 3d mirror symmetry; and (3) the functionalities of 2d mirror symmetry control the gluing of 3d mirrors.
+  Sobhan Seyfaddini (ETH Zürich)
+h30, Salle B217
+  Closing Lemmas on Symplectic Manifolds
+Given a diffeomorphism of a manifold, can one perturb it to create a periodic orbit passing through a specified region? This question, first raised in the 1960s, is known as the Closing Lemma. While the problem was resolved positively in C^1 regularity long ago, it remains largely open at higher levels of smoothness. Recent years have seen significant progress in the C^\infty setting, particularly for area-preserving maps on surfaces. In this talk, I will review these developments, highlighting works by Asaoka, Irie, Cristofaro-Gardiner, Edtmair, Hutchings, Prasad, and Zhang. I will also present some recent joint work with Cineli & Tanny and Mak & Smith, including partial results in higher dimensions.
+**2025, March 24, Monday, Université de Genève**
+  Lionel Lang (Gävle)
+h00, Salle 01-15
+  Logarithmic volumes of holes of hypersurfaces and tropicalization of periods
+Integrating the logaritmic volume form on well chosen discs bounded on hypersurfaces gives a local system of coordinates on the linear system of such hypersurfaces. Surprisingly, the same procedure gives global coordinates on the corresponding linear system of tropical hypersurfaces. In both the algebraic and tropical settings, the differential of these coordinate systems with respect to the coefficents of the defining equations are period matrices.  I want to discuss how this observation can be used to study the tropicalization of periods of hypersurfaces.
+  Johannes Rau (Universidad de los Andes)
+h00, Salle 06-13
+  Welschinger-Witt invariants
+The "quadratically enriched" invariants defined by Kass-Levine-Solomon-Wickelgren are obtained by counting rational curves over an arbitrary ground field and take values in the associated Witt-ring of quadratic forms. Specializing these values to rank and signature reproduces the corresponding Gromov-Witten and Welschinger invariants, respectively. In my talk, I want to introduce the concept of a Witt invariant which can be computed in terms of multiquadratic and multireal field extensions. We will see that Welschinger invariants give naturally rise to such an Witt invariant which in some cases (conjecturally always) coincides with the quadratically enriched invariants.
 **2024, December 6, Friday, Université de Genève**

AV����Ƶ

�پ��ڴ�é����Գ����

AV��Ƶ

�پ��ڴ�é��Գ��