Planned seminars

Room P3.10, Mathematics Building Instituto Superior Técnico

Carlos Florentino

, Universidade de Lisboa - Faculdade de Ciências

Following A. Beauville, a complex algebraic variety $X$ is said to be symplectic if it admits a holomorphic symplectic form $\omega$ on its smooth locus such that, for every resolution $\pi: Y \to X$, $\pi^*\omega$ extends to a holomorphic $2$-form on $Y$. When this extension is actually non-degenerate (a de facto symplectic form) on $Y$, we call $\pi$ a symplectic (or crepant) resolution.

Let $G$ be a complex reductive group and $A$ an abelian variety of dimension $d$. The aim of this talk is to show that all moduli spaces of $G$-Higgs bundles over $A$ are symplectic varieties, and that, for $G=\mathrm{GL}(n,\mathbb C)$, the canonical Hilbert-Chow morphism is a symplectic resolution if and only if $d=1$.

Moreover, using a little representation theory, we can obtain explicit expressions for the Poincaré polynomials of all Hilbert-Chow resolutions (either $d=1$, all $n$; or $n=1,2,3$ and all $d$). This is joint work with I. Biswas and A. Nozad.


Brayan Ferreira

, Universidade Federal do Espírito Santo

The question whether a symplectic manifold embeds into another is central in symplectic topology. Since Gromov nonsqueezing theorem, it is known that this is a different problem from volume preserving embedding. There are several nice results about symplectic embeddings between open subsets of $\mathbb R^{2n}$ showing that even for those examples the question can be completely nontrivial. The problem is substantially more well understood when the manifolds are toric domains and have dimension $4$, mostly because of obstructions coming from embedded contact homology (ECH). In this talk we are going to discuss symplectic embedding problems in which the target manifold is the disk cotangent bundle of a two-dimensional sphere, i.e., the set consisting of the covectors with norm less than $1$ over a Riemannian sphere. We shall talk about some tools such as ECH capacities and action angle coordinates. Much of this talk is based on joint works with Vinicius Ramos and Alejandro Vicente.

Room P3.10, Mathematics Building Instituto Superior Técnico

Manuel Krannich

, Karlsruhe Institute of Technology

One of the distinctive feature of the $d$-dimensional torus $T^d$ is that it admits a faithful smooth action by $\mathrm{SL}_d(\mathbb Z)$, so one might wonder whether such an action (or any nontrivial action) also exists for exotic tori i.e. smooth $d$-manifolds that are homeomorphic but not diffeomorphic to $T^d$. I will discuss this and related questions in the talk, based on joint work with M. Bustamante, A. Kupers, and B. Tshishiku.


Martin Pinsonnault

Martin Pinsonnault, University of Western Ontario
To be announced


Eleonora Di Nezza

, Sorbonne Université (IMJ-PRG) and École Normale Supérieure de Paris (DMA).

Studying metrics with special curvature properties on compact Kähler manifolds is a fundamental problem in Kähler geometry. In this talk, I will focus on the existence and uniqueness of singular Kähler-Einstein metrics whose singular behavior is prescribed. These results are based on a series of joint works with T. Darvas and C. Lu.