Humboldt-Universität zu Berlin
Mathem.-Naturwissenschaftliche Fakultät
Institut für Mathematik

Forschungsseminar "Algebraische Geometrie"

Sommersemester 2019

Das Forschungsseminar findet mittwochs in der Zeit von 13:00 - 15:00 Uhr in der Rudower Chaussee 25, 12489 Berlin-Adlershof, Raum 1.114, statt.

Seminar: Algebraic Geometry an der FU

10.04.2019 Stefan Schreieder (LMU München)
Title: On deformations of quintic and septic hypersurfaces

Abstract: An old question of Mori asks whether in dimension at least three, any smooth specialization of a hypersurface of prime degree is again a hypersurface. A positive answer to this question has up till now only been known in degrees two and three. In this talk I explain how to settle the case of quintics (in arbitrary dimension) and septics in dimension three. Our results follow from numerical characterizations of the corresponding hypersurfaces. In the case of quintics, this extends famous work of Horikawa who analysed deformations of quintic surfaces. Joint work with J.C. Ottem.
15.05.2019 13:15 - 14:30 Mihai Paun (Universität Bayreuth)
Title: On the algebraicity of holomorphic foliations.

Abstract: We will report on a recent joint work with J. Cao and F. Campana. Our main result is an algebraicity criteria for holomorphic foliations with trivial first Chern class.
14:45 - 16:00 Rahul Pandharipande (ETH Zurich)
Title: Virtual Euler characteristics of Quot scheme of surfaces.

Abstract: Let S be a nonsingular projective surface. Quot schemes of quotients on S with supports of dimensions 0 and 1 always have 2-term obstruction theories (and therefore also have natural virtual fundamental classes). I will explain what we know about the virtual Euler characteristics in this theory: theorems, conjectures, and a lot of examples. Joint work with Dragos Oprea.
22.05.2019 Evgeny Shinder (University of Sheffield).
Title: Variation of stable birational types of hypersurfaces.

Abstract: I will explain the rationality problem for hypersurfaces of high degree, and show how the specialization for the Grothendieck ring of varieties allows to prove that very general hypersurfaces of high degree are not stably birational to each other..
04.06.2019 11 - 13 BMS Room Gavril Farkas (HU Berlin) and Bernd Sturmfels (MPI-MiS Leipzig and UC Berkeley).
Title: Problems for the MATH+ Algebraic Geometry program.

Abstract: A discussion on some problems for the upcoming MATH+ Algebraic Geometry Semester.
05.06.2019 Yohan Brunebarbe (CNRS Bordeaux).
Title: o-minimal geometry and algebraicity of period maps.

Abstract: In this talk I will introduce o-minimal geometry and illustrate its relevance to proving algebraicity of certain analytically defined objects. As an application, I will explain that the period maps associated to variations of pure Hodge structures are algebraic in corestriction to their image, as conjectured by Griffiths. This is joint work with Benjamin Bakker and Jacob Tsimerman..
26.06.2019 Seminar postponed until next week.
03.07.2019 13:15 - 14:30 Paweł Borówka (Uniwersytet Jagielloński Kraków).
Title: Klein coverings of genus 2 curves.

Abstract: In the talk, we will describe the geometry of etale 4:1 coverings of genus 2 curves given by a Klein group. The moduli of such coverings has 2 connected components that aredistinguished by the value of the Weil pairing on the group. We will show that in both cases, everything can be readfrom the 6 branch points of the curve. As a main result, we will describe the Prym variety of a covering and show that the Prym map is injective. This is a joint work with Angela Ortega.
14:45 - 16:00 Mario Kummer (Technische Universität Berlin).
Title: Positive Definite Ulrich Bundles

Abstract: I will explain how Ulrich bundles and secant varieties of curves can be used for approaching certain questions that arise in the theory of convex optimization. This is joint work with Rainer Sinn.


Wintersemester 2018/19

Sommersemester 2018

Wintersemester 2017/18

Sommersemester 2017

Wintersemester 2016/17

Sommersemester 2016

Wintersemester 2015/2016

Sommersemester 2015

Wintersemester 2014/15

Sommersemester 2014

Wintersemester 2013/14

Sommersemester 2013

Wintersemester 2012/13

Sommersemester 2012

Wintersemester 2011/12

Sommersemester 2011

Wintersemester 2010/11