Mardi 16 décembre 2014
IRMA
The "Joint Seminar in Algebraic and Complex Geometry" is a research seminar, organized by the research groups in Basel, Freiburg, Nancy and Strasbourg. The seminar meets roughly twice per semester in Strasbourg, for a full day. There are about four talks per meeting, both by invited guests and by speakers from the organizing universities. We aim to leave ample room for discussions and for a friendly chat.
The talks are open for everyone. Contact one of the organizers if you are interested in attending the meeting. We have some (very limited) funds that might help to support travel for some junior participants.
The seminar will meet in Strasbourg, December 16th in the conference room of the institute.
Organizer : G. Pacienza (Strasbourg)
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Mardi 16 décembre 2014
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10:30
Damien Mégy, Nancy
The period map of certain families of singular hypersurfaces
This is a joint work with Philippe Eyssidieux. We consider a natural Deligne-Mumford stack parametrizing degree d hypersurfaces of IP^n with ADE singularities, and prove an infinitesimal Torelli property along the stacky strata. This construction gives rise to examples of smooth projective varieties with interesting fundamental groups and universal covers. If time permits, I will discuss the Toledo and Shafarevich conjecture for these examples. -
11:45
Jean-Philippe Furter, La Rochelle
Some properties of the group GL2(\C[x1,…,xm]) and some applications to the polynomial automorphism group Aut(A^n) of the affine space A^n
The groups GL2(\C[x1,…,xm]) and Aut(A^n) can naturally be considered as ind-groups (algebraic groups of infinite dimension). As such, they are endowed with the Zariski topology. We will describe several topological properties of these two groups. In particular, we will give examples of closed subgroups. -
14:00
Behrouz Taji, Freiburg
Semistable reflexive sheaves over klt spaces
We prove that any semistable reflexive sheaf over a klt projective variety with vanishing orbiflod Chern classes comes form a linear representation of π1(Xreg). In the smooth setting such a correspondence goes back to the classical results of Narasimhan-Seshadri , Donaldson-Uhlenbeck-Yau and subsequently Simpson. As an application we establish a characterization of finite quotient of Abelian varieties via vanishing of orbifold Chern classes. This is a joint work with Steven Lu. -
16:00
Paolo Cascini, Imperial College (London)
Toroidal modifications
I will survey on a conjecture due to Shokurov on the ACC for the set of minimal log discrepancies and I will describe an approach towards this conjecture using toroidal modifications. Joint work with J. McKernan.