Symplectix 28 juin 2024

 Location: IHP, room 201

The talks are broadcasted via Zoom:
https://zoom.us/j/89445897442?pwd=QmVZWHBiM2Nwb09yUVJERnYrSHJrUT09

 
9:30 Matija Sreckovic (ENS)  
Link between Flow Categories of Morse Functions and Fukaya
Categories of Lefschetz Fibrations on the Cotangent Bundle.
Abstract: I will start the talk by explaining some concepts used in Emmanuel
Giroux's construction of a Lefschetz fibration on the cotangent bundle
which extends a given Morse function on the zero section. I will then
state a variant of a conjecture by Paul Seidel on a link between the flow
category of the Morse function and the directed Donaldson-Fukaya category
of the Lefschetz fibration. In the main part of the talk, I will explain
how to prove this conjecture in dimension 2, and some progress I've made
in dimension 3. The main tool in the proof is an explicit handle
decomposition of the real regular fibers of the Lefschetz fibration, which
allows us to see what the vanishing cycles look like.

10:45 Simon Vialaret (Bochum and Orsay)  
Systolic inequalities for S^1-invariant contact forms.
Abstract: In Riemannian geometry, a systolic inequality aims to give a uniform bound on the length of the shortest closed geodesic for metrics with fixed volume on a given manifold. This notion generalizes to contact geometry, replacing the geodesic flow by the Reeb flow, and the length by the period. As opposed to the Riemannian case, it is known that there is no systolic inequality for general contact forms on a given contact manifold. In this talk, I will state a systolic inequality for contact forms that are invariant under a circle action in dimension 3, and give applications to Finsler geodesic flows and to a conjecture of Viterbo.

14:00 Adrien Currier (Nantes)
About the nearby Lagrangian conjecture in locally conformally symplectic geometry.

Abstract: Locally conformally symplectic (lcs) geometry is a generalization of symplectic geometry in which a manifold is endowed with a non-degenerate 2-form that is locally a symplectic form up to some positive factor. If the local behavior of such a manifold is largely identical to that of a symplectic manifold, the global behavior can nonetheless vastly differ. For example, while it is possible to define Lagrangian submanifolds in lcs geometry, we also have to contend with the fact that S^3 \times S^1 has a canonical "exact" lcs structure given  by the canonical contact form of S^3 through a process known as circular lcs-ization.
The foremost goal of this talk will be to familiarize the public with lcs geometry and its ties to other branches geometry, most notably contact geometry. To do this, I will use a couple of results I have obtained during my thesis as a narrative thread. These results will focus on the nearby Lagrangian conjecture in lcs geometry and, more specifically, on the possibility of an lcs adaptation of the Abouzaid-Kragh theorem.


Other symplectic activity in Paris:

- Séminaire Nantes-Orsay
- Symplectic Zoominar (every Fridays except Symplectix' Fridays at 15:15, Paris time)
- Soutenance de thèse de Francesco Morabito le 26 juin à 16h, Ecole Polytechnique, amphi Becquerel.

Symplectix 26 avril 2024

Location: IHP, room 314

The talks are broadcasted via Zoom:
https://zoom.us/j/89445897442?pwd=QmVZWHBiM2Nwb09yUVJERnYrSHJrUT09

 
10:45 Laurent Côté (Bonn)  
Morse-Bott methods in Floer homotopy theory.
Abstract: I will talk about a joint project with Y. Baris Kartal whose purpose is to incorporate Morse--Bott methods into Floer homotopy theory. Morse--Bott methods have the prospect of being useful for two reasons. First, they simplify equivariant constructions: for example, we used these methods to define a lift of circle equivariant symplectic homology to equivariant spectra.  Second, they enable new computations. As a step in this direction, we used Morse--Bott methods to compute the (equivariant) local Floer homology of the orbit of an autonomous Hamiltonian, but I hope and expect that one can push such computations significantly further.
 

14:00 Georgios Dimitroglou Rizell (Upsala)
Non-shrinking of Legendrians in prequantization bundles and non-squeezing of open subsets.

Abstract: We use a version of Rabinowitz-Floer homology for Legendrians defined using Symplectic Field Theory, and its filtered invariance, to show that Legendrian lifts of Bohr—Sommerfeld Lagrangians cannot be ``shrunk’’ by Legendrian isotopy. Applications includes contact non-squeezing results for preimages of symplectic balls and cubes under the prequantization-bundle projection. This is joint work in progress with M. Sullivan.


15:45
Abigail Ward (Cambridge)  CANCELLED



Other symplectic activity in Paris:

- Séminaire Nantes-Orsay
- Symplectic Zoominar (every Fridays except Symplectix' Fridays at 15:15, Paris time)

Symplectix 5 avril 2024

Location: IHP, room 201

The talks are broadcasted via Zoom:
https://zoom.us/j/89445897442?pwd=QmVZWHBiM2Nwb09yUVJERnYrSHJrUT09

 
10:45 David Bechara Senior (Aachen) 
The asymptotic action of area preserving disk maps and some of its properties.
Abstract: Given a diffeomorphism of the disk that preserves the standard symplectic form, I will introduce the asymptotic action associated to this map. I will then show a pointwise formula relating the asymptotic action to the asymptotic winding number of pairs of points. As a corollary one obtains a generalization for a well known result by A. Fathi which gives a formula for the Calabi invariant of a disk map in terms of its mean winding numbers. Additionally I will focus on how this formula can be used to study symplectic dynamical information for irrational pseudo-rotations of the disk. This talk includes joint work with Patrice Le Calvez and Abror Pirnapasov.
 

14:00 Yanki Lekili (London)
New orders associated with terminal threefold singularities.
Abstract: This is based on joint work with Jenia Tevelev. I will tell you a story of a vector bundle due to Kawamata that captures the "categorical essence" of certain terminal 3-fold singularities. Our computations are done in the mirror via Floer theory but it teaches us (with a proof!) something new about derived categories of terminal threefold singularities and noncommutative algebra by providing explicit deformations of the so-called Kalck-Karmazyn algebra associated with cyclic quotient surface singularities.


15:45
Salammbo Connolly (Orsay)
On torsion in (bi)linearized Legendrian contact homology.

Abstract:
Given a Legendrian submanifold in a contact manifold, one can define its Legendrian Contact Homology (LCH). This invariant is unfortunately difficult to compute. However, there exist two more computable variants, linearized LCH (defined by Chekanov), and bi-linearized LCH (defined by Bourgeois and Chantraine). For legendrian knots in R^3, very little is known about the possibility of having torsion in these invariants when they are defined over integer coefficients. In joint work with Frédéric Bourgeois, we give properties of torsion that can appear in linearized LCH with integer coefficients, and also give the full geography of bi-linearized LCH with integer coefficients.


Next Symplectix:
 

26/04 (Coté, Ward, Dimitroglou-Rizell)

Other symplectic activity in Paris:

- Mini-course of Shaoyun Bai in the week 11/03-14/03
- Séminaire Nantes-Orsay
- Symplectic Zoominar (every Fridays except Symplectix' Fridays at 15:15, Paris time)