Programme:
Florent Balacheff (Lille) Contact perturbation theory and a question of Viterbo
Abstract: Over ten years ago Claude
Viterbo asked whether the ball in $R^{2n}$ has the
largest symplectic capacity among all convex bodies of a
given volume. In this talk we shall give various partial
(affirmative) answers to this question by adapting the
perturbative techniques of celestial mechanics to study
the dynamics of Reeb flows. |
Remi Cretois (Lyon) Real automorphisms of a vector bundle and Cauchy-Riemann operators
Abstract: We consider a complex vector
bundle N equipped with a real structure c_N over a real
curve (\Sigma_g,c_\Sigma) of genus g. The set of all Cauchy-Riemann operators on (N,c_N) is a contractible
space. The determinant bundle over this space is a real
line bundle whose fiber at given operator is its determinant. We will try to
describe the action |
Jacqueline Espina (Lyon) The mean Euler characteristic of contact structures
Abstract: The mean
Euler characteristic (MEC) of a contact manifold is an
invariant that arises in contact homology. True to its
name, the mean Euler characteristic is the average
alternating sum of the ranks of cylindrical or
linearized contact homology. This is a powerful enough
invariant to distinguish inequivalent contact structures
within the same homotopy class. We will give an
expression of the MEC in terms of local properties (the
Conley-Zehnder and mean indices) of closed Reeb orbits
for a broad class of contact manifolds, the the so-called
asymptotically nite contact manifolds. This class is
essentially closed under subcritical contact surgery and
we will see that the MEC changes under such surgery in a
very simple way. Furthermore, we will give an expression
for he mean Euler characteristic in the Morse-Bott case
and calculate the MEC for some examples. |
Helene Eynard Bontemps (Paris) Homotopy of codimension one foliations on 3-manifolds
Abstract: We are
interested in the topology of the space of smooth
codimension one foliations on a given closed 3-manifold.
In 1969, J. Wood proved that any smooth plane field on a
closed 3-manifold can be deformed into a plane field
tangent to a foliation. This fundamental result was then
reproved and generalized by W. Thurston. |
Jonathan Evans (Zurich) Quantum cohomology of twistor spaces
Abstract: Monotone symplectic (aka symplectic Fano) manifolds are pretty rare in the universe of all symplectic manifolds, in much the same way that Fano varieties or Ricci-positive manifolds are rare. Positivity usually has strong implications for the underlying topology and one wonders if the same is true here. However, the twistor space of a hyperbolic 2n-manifold M (n bigger than or equal to 3) was observed to be a monotone symplectic manifold by Fine and Panov in 2009 and these examples counter many of one’s expectations of what a symplectic Fano manifold ought to look like. We explore the symplectic topology of these spaces (for the simplest case n=3) further by computing their quantum cohomology ring and the self-Floer cohomology of certain natural (equally unexpected) monotone Lagrangian submanifolds (Reznikov Lagrangians) associated to totally geodesic n-dimensional submanifolds of M. We will see evidence that there might be (yet more unusual) Lagrangians hiding in these spaces that we haven't yet observed. |
Penka Georgieva( Princeton) Orientability and Open Gromov-Witten Invariants
Abstract: I will first discuss the orientability of the moduli spaces of J-holomorphic maps with Lagrangian boundary conditions. It is known that these spaces are not always orientable and I will explain what the obstruction depends on. Then, in the presence of an anti-symplectic involution on the target, I will give a construction of open Gromov-Witten disk invariants. This is a generalization to higher dimensions of the works of Cho and Solomon, and is related to the invariants defined by Welschinger. |
Clement Hyvrier( Uppsala) On symplectic uniruling of Hamiltonian fibrations.
Abstract: A
symplectic manifold is said to be symplectically
uniruled if there is a non vanishing genus zero Gromov-Witten
invariant with one point constraint. It is known that
symplectic uniruledness of a closed Hamiltonian
fibration over a symplectic base is induced from
symplectic uniruledness of its fiber. We will show,
under some assumptions, that the same applies when we
require the base to be symplectically uniruled instead.
As a consequence such fibrations verify the Weinstein
conjecture for separating hypersurfaces, due to work of
Lu (following previous results of Hofer-Viterbo and
Li-Tian). |
Yael Karshon (Toronto) Counting toric actions
Abstract: In how many
different ways can a two-torus act on a given simply
connected symplectic four-manifold? If the second Betti
number is one or two, the answer has been known |
Samuel Lisi (Brussels) Fillings of spinal open books
Abstract: A
spinal open book on a contact manifold is a
generalization of a supporting open book. Open books
arise naturally as the boundary of a Lefschetz fibration
over a disk. Similarly, spinal open books arise as the
boundary of a Lefschetz fibration over a more general
surface |
Ignasi Mundet i Riera (Barcelona) Loops of homeomorphims of adjoint orbits
Abstract: Let $G$ be a compact
Lie group and let ${\mathcal O}\subset{\mathfrak g}$ be
an adjoint orbit of $G$. Our aim is to talk about the
proof that the morphism |