|22/05/20||Seminario||15:15||16:15||1101 D'Antoni||Georg Schumacher||Philipps-Universität Marburg|
|15/05/20||Seminario||15:15||16:15||1101 D'Antoni||Luca Tasin||Università di Milano|
|08/05/20||Seminario||15:15||16:15||1101 D'Antoni||Roberto Svaldi||Ecole polytechnique fédérale de Lausanne|
|24/04/20||Seminario||15:15||16:15||1101 D'Antoni||Gabriele Benedetti||Heidelberg University|
|17/04/20||Seminario||15:15||16:15||1101 D'Antoni||Giulia Saccà||Columbia University|
|27/03/20||Seminario||15:15||16:15||1101 D'Antoni||Arvid Perego||Università di Genova|
|20/03/20||Seminario||15:15||16:15||1101 D'Antoni||Thomas Kraemer||Humboldt-Universität zu Berlin||A converse to Riemann's theorem on Jacobian varieties|
Jacobians of curves have been studied a lot since Riemann’s theorem, which says that their theta divisor is a sum of copies of the curve.
Similarly, for intermediate Jacobians of smooth cubic threefolds
Clemens and Griffiths showed that the theta divisor is a sum of two
copies of the Fano surface of lines on the threefold. We prove that
in both cases these are the only decompositions of the theta
divisor, extending previous results of Casalaina-Martin, Popa and
Schreieder. Our ideas apply to a much wider context and only rely on
the decomposition theorem for perverse sheaves and the
representation theory of reductive groups.
|06/03/20||Seminario||15:15||16:15||1101 D'Antoni||Andreas Knutsen||Bergen University||Moduli of polarized Enriques surfaces
Moduli spaces of polarized Enriques surfaces have several irreducible components, even if one fixes the degree of the polarization. I will present some results concerning these spaces. In particular I will answer a question of Gritsenko and Hulek concerning connectedness of the étale double covers from the moduli spaces of polarized Enriques surfaces to the moduli spaces of numerically polarized such surfaces, and I will give a way to determine all irreducible components of these moduli spaces. This talk is part of the activity of the MIUR Excellence Department Project CUP E83C18000100006.
|06/03/20||Seminario||14:00||15:00||1101 D'Antoni||Mattia COLOMA||Università di Roma "Tor Vergata" ||The Hirzebruch-Riemann-Roch theorem in the fancy language of Spectra
The category of spectra indubitably is the best of possible worlds for cohomology theories. For instance in spectra one can start with a few basic morphisms, be confident that every natural diagram built from them will commute, and end up with a proof of the Hirzebruch-Riemann-Roch theorem. As in every good story we'll have a deus ex machina: Atiyah's identi-fication of the Spanier-Whitehead dual of a manifold with the Thom spectrum of minus its tangent bundle. I will try to gently introduce all of these tools assuming basic notions of topology, geometry and algebra. Based on joint work with Domenico Fiorenza and Eugenio Landi.
|28/02/20||Seminario||15:15||16:15||1101 D'Antoni||Laura Pertusi||Università di Milano||Stability conditions on Gushel-Mukai varieties
A generic Gushel-Mukai variety X is a quadric section of a linear section of the Grassmannian Gr(2,5). Kuznetsov and Perry proved that the bounded derived category of X has a semiorthogonal decomposition with exceptional objects and a non-trivial subcategory Ku(X), known as the Kuznetsov component. In this talk we will discuss the construction of stability conditions on Ku(X) and, consequently, on the bounded derived
category of X. As applications, for X of even-dimension, we will construct locally complete families of hyperkaehler manifolds from moduli spaces of stable objects in Ku(X) and we will determine when X has a homological associated K3 surface. This is a joint work with Alex Perry and Xiaolei Zhao.