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

--- symplectic [2025/10/14 20:01] – g.m
+++ symplectic [2026/04/29 00:05] (Version actuelle) – g.m
@@ Ligne 1: / Ligne 1: @@
 ===== GeNeSys: Geneva-Neuchâtel Symplectic geometry seminar =====
+**2026, April 28, Tuesday, Université de Neuchâtel**, Rue Emile-Argand 11, Room B217
+h Erman Cineli (ETH Zürich, Switzerland) "Topological entropy and Floer theory".
+Abstract:
+In this talk we discuss connections between Floer theory and dynamics of Hamiltonian systems, focusing on the barcode entropy of Hamiltonian diffeomorphisms and Reeb flows. Barcode entropy is the exponential growth rate of the number of not-too-short bars in the Floer or symplectic homology persistence module. The topological entropy bounds from above the barcode entropy and, conversely, the barcode entropy admits lower bounds coming from hyperbolic invariant sets. As a consequence, the two quantities are equal in low dimensions. The talk is based on joint work with Viktor Ginzburg, Basak Gurel and Marco Mazzucchelli.
+h Peter Albers (Universität Heidelberg) "Outer symplectic and length billiards at infinity".
+Abstract:
+We define outer symplectic and length billiards on vector spaces and discuss basic properties. The former is defined in arbitrary even dimensions, the latter in dimension 2. Both are symplectic, the former with respect to the standard symplectic form the latter not. However, both these discrete dynamical systems (actually their second iteration) far away from the billiard table can be approximated by continuous (and Hamiltonian) systems. The construction of these Hamiltonians involves in both cases symplectic polar duality. This is joint work with Ana Chavez Caliz, Lael Costa and Sergei Tabachnikov.
+**2026, March 3, Tuesday, Université de Genève**, the seminar room on the 8th floor.
+h30 Marcelo Alves (Augsburg) "Polytopes and C^0-Riemannian metrics
+with positive topological entropy".
+Abstract: The topological entropy of geodesic flows has been extensively studied since the foundational works of Dinaburg and Manning. It measures the exponential complexity of the geodesic flow of a Riemannian
+manifold, and there are several results connecting it to the geometry and topology of a Riemannian manifold. In this talk I will explain how recent advances in symplectic dynamics can be used to give a meaningful extension of the topological entropy to C^0-Riemannian metrics; i.e. Riemannian metrics which are continuous but not necessarily differentiable. Similarly, using contact geometry we will explain how we
+can talk in a meaningful way about the topological entropy of convex and starshaped polytopes in R^4, thinking of them as a C^0-contact form. This is joint work with Matthias Meiwes.
+h Stepan Orevkov (Toulouse) "On curves of degree 10 with 12 triple
+points".
+Abstract. We construct an irreducible rational curve of degree 10 in CP^2 which has 12 triple points, and a union of three rational quartics with 19 triple points. This gives counter-examples to a conjecture by Dimca, Harbourne, and Sticlaru. We also prove that there exists an analytic family $C_u$ of curves of degree 10 with 12 triple points which tends as $u \to 0$ to the union of the dual Hesse
+arrangement of lines (9 lines with 12 triple points) with an additional line. We hope that our
+approach to the proof of the latter fact could be of independent interest.
+**2025, Nov 11, Tuesday, Université de Neuchâtel**
+  Oliver Edtmair (ETHZ)
+h30 B217
+  Volume filling ellipsoids
+I will explain how to fill the full volume of any compact connected symplectic 4-manifold with smooth boundary with a single symplectic ellipsoid. This can be seen as a strong version of Biran’s famous packing stability theorem and has interesting consequences concerning the subleading asymptotics of various symplectic Weyl laws. The embedding construction relies on a quantitative refinement of Banyaga’s classical theorem on the simplicity and perfectness of Hamiltonian diffeomorphism groups, which I will also explain. Recently, Cristofaro-Gardiner and Hind constructed symplectic domains (with non-regular boundary) for which packing stability breaks down. I will explain some progress towards pinpointing the exact transition point between packing stability and failure thereof and mention open questions and conjectures.
+  Filip Brocic (Augsburg)
+h30 B217
+  Parametric Gromov width in Liouville domains
+In the talk, I will introduce the notion of the parametric Gromov width motivated by the classical camel theorem. The main theorem is a method how to bound the parametric Gromov width in the case of Liouville domains using the structure of the BV algebra on the persistence module that recovers symplectic cohomology. After presenting the theorem, I will cover main applications mainly using the string topology on cotangent bundles. In particular, I will give a new proof of the camel theorem using our methods. Time permitting, I will explain the method of the proof of the main theorem. This talk is based on the joint work with Dylan Cant.
 **2025, Oct 17, Friday, Université de Genève**
@@ Ligne 7: / Ligne 54: @@
   Quantum numbers, braids and knots
-  Abstract{{ :0:geneve-2025.pdf |}}
+  https://www.unige.ch/math/tggroup/lib/exe/fetch.php?media=0:geneve-2025.pdf
 **2025, Sep 18-21, Les Marécottes, Hotel " Aux Mille Etoiles ", Workshop "Plane curves and symplectic geometry" **