### Table des matières

# Web-page of the Geneva University tropical group

PhD graduated: Kristin Shaw (December 2011), Lionel Lang (December 2014), Nikita Kalinin (December 2015), Mikhail Shkolnikov (June 2017), Johannes Josi (February 2018).

Current members:Thomas Blomme, Weronika Czerniawska, Grigory Mikhalkin, Alina Pavlikova, Mikhail Pirogov.

Alumni: Ivan Bazhov, Johan Bjorklund, Rémi Crétois, Yi-Ning Hsiao, Jens Forsgard, Maxim Karev, Ilya Karzhemanov, Sergei Lanzat, Michele Nesci, Johannes Rau, Arthur Renaudineau.

We organize several seminars:

Séminaire "Fables Géométriques".

pre-2017 Battelle Seminar and

Tropical working group Seminar.

Also, you can check how tropical curves (and hypersurfaces, in general) emerge from abelian sandpile models: tropicalsand

# Seminars and conferences

**2022, September 27, Tuesday, Université de Neuchâtel**

Richard Hind (University of Notre Dame) Obstructing Lagrangian isotopies Room B107, 14:00

**Abstract:**

I will describe some obstructions to the existence of Lagrangian tori in subsets of Euclidean space, and also to isotopies between the tori. The obstructions come from holomorphic curves and In simple situations are sharp. As a consequence we can derive obstructions to certain 4 dimensional symplectic embeddings, which turn out not to be especially strong, but the analysis does lead to precise statements about stabilized ellipsoid embeddings. Results are taken from joint works with Emmanuel Opshtein, Jun Zhang and Kyler Siegel and Dan Cristofaro-Gardiner.

Joé Brendel (Université de Neuchâtel and Tel Aviv University) Lagrangian tori in S^2 x S^2 Room E213, 16:00

**Abstract:**

There is an obvious family of Lagrangian tori in $S^2 \times S^2$, namely those obtained as a product of circles in the factors. We discuss the classification of such product tori up to symplectomorphisms and note that the non-monotone case is qualitatively very different from the monotone one. In the proof, we use a symmetric version of McDuff's probes. The resulting classification can be used to tackle many related questions: Which of the above tori are the image of a product torus in a ball under a Darboux embedding? What is the Hamiltonian monodromy group of the product tori? How many disjoint copies (up to Hamiltonian isotopy) of a given product torus can be packed into the ambient space? Why does the Lagrangian analogue of the flux conjecture fail so badly? If time permits we will say something about exotic tori, i.e. tori which are not symplectomorphic to product tori. This is partially based on joint work with Joontae Kim.

# Geneva-Neuchâtel Symplectic Geometry Seminar

Schedule and more details: seminar page

We had our page http://www.unige.ch/math/folks/langl/battelle/

Also, there is **Séminaire de Géométrie Tropicale** in Paris:http://erwan.brugalle.perso.math.cnrs.fr/Seminaires/Geotrop/Geotrop.html

# About this page

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).

Page creating is simple, just add internal link on non-existing page from existing.

For example еуые: .

Google “docuwiki …” to know how to do something if it is not clear.

Send me your nickname and password - to have right to create and edit pages.

Latex support is here. $\int \mathbb C + \prod\limits_{x\to \infty} f^g$