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Talks and seminars, possibly part of a conference or series.

Virtual Classes in Algebraic Cobordism

Posted in
Speaker: 
Timo Schürg
Affiliation: 
MPI
Date: 
Tue, 2013-01-22 14:00 - 15:00
Location: 
MPIM Lecture Hall
Parent event: 
Seminar on Algebra, Geometry and Physics 
Virtual fundamental classes admit a natural description as orientation or Gysin maps for quasi-smooth morphisms of derived schemes. We show that Algebraic Bordism as developed by Levine and Morel admits such orientations, and thus there exist fundamental classes in Algebraic Bordism. We then present a theory of derived algebraic bordism, which uses quasi-smooth derived schemes as
generators instead of only smooth schemes. This is the universal homology theory having orientations for quasi-smooth morphisms.

Mirror symmetry and Fano classification

Posted in
Speaker: 
Alessio Corti
Date: 
Thu, 2012-12-20 15:00 - 16:00
Location: 
MPIM Lecture Hall
Parent event: 
Galois representations and pencils of Calabi-Yau motives
Parent event: 
MPI-Oberseminar

MPI-Oberseminar/Worshop Galois represenations and pencils of Calabi-Yau motives

In this talk, a Laurent polynomial f is mirror-dual to a Fano manifold X if the Picard-Fuchs operator
of f equals the quantum differential operator of X. I introduce the class of Minkowski polynomials
and show how to use them to derive the classification of Fano 3-folds (Iskovskikh, Mori--Mukai)
from. I outline a program to classify Fano 4-folds using these ideas. At the end I briefly touch
on extremal and low ramification sheaves.

Hodge theory and derived categories of cubic fourfolds (work of Addington and Thomas)

Posted in
Speaker: 
Ziyu Zhang
Date: 
Mon, 2012-12-10 16:15 - 17:45
Location: 
MPIM Seminar Room
Parent event: 
Derived categories of coherent sheaves

Modular construction of mixed motives and congruences

Posted in
Speaker: 
Guenter Harder
Affiliation: 
MPI
Date: 
Tue, 2012-12-18 12:00 - 12:50
Location: 
MPIM Lecture Hall
Parent event: 
Conference "Galois representations and pencils of Calabi-Yau motives"

I will briefly describe a construction of mixed (Anderson) motives for the symplectic group $GSp_2$. These mixed motives are labelled by  automorphic cusp forms $f$ on $Sl_2$ and they are extensions of pure Tate motives. I will give a formula for the Betti-de-Rham extension classes. Some rather speculative arguments suggest that these motives "create" congruences between elliptic and Siegel modular forms. These congruences have been checked in experiments by Berstroem, Faber, van der Geer and Ghitza, Ryan and Sulon.

t.b.a.

Posted in
Speaker: 
Alexei Panchishkin
Date: 
Tue, 2012-12-18 11:00 - 11:50
Location: 
MPIM Lecture Hall
Parent event: 
Conference "Galois representations and pencils of Calabi-Yau motives"

Introduction to Frobenius in q-difference equations

Posted in
Speaker: 
Lucia Di Vizio
Date: 
Tue, 2012-12-18 10:00 - 10:50
Location: 
MPIM Lecture Hall
Parent event: 
Conference "Galois representations and pencils of Calabi-Yau motives"

An amazing coincidence of formulas for the unit root part of crystalline cohomology and the density of states for physical crystals

Posted in
Speaker: 
Jan Stienstra
Affiliation: 
Utrecht
Date: 
Tue, 2012-12-18 14:00 - 15:00
Location: 
MPIM Lecture Hall
Parent event: 
Conference "Galois representations and pencils of Calabi-Yau motives"

Certain Laurent polynomials can be viewed as discretizations of a Laplace operator with quasi-periodic boundary conditions. The eigenvalue/eigenfunction equation for this situation then describes the level sets of the Laurent polynomial. The density of states is a measure for the size of these level sets as a function of the level. It can be approximated, in yet another discretization, by counting how the points of which the coordinates are N-th roots of 1 are distributed over the various level sets.

Vortices and quantum Kirwan maps

Posted in
Speaker: 
Fabian Ziltener
Organiser(s): 
KIAS, Seoul
Date: 
Wed, 2012-12-12 15:15 - 16:00
Location: 
Hausdorff Research Institute for Mathematics
Parent event: 
Vortex Seminar

ortices and quantum Kirwan maps

Posted in
Speaker: 
Fabian Ziltener
Organiser(s): 
KIAS, Seoul
Date: 
Wed, 2012-12-12 14:00 - 15:00
Location: 
Hausdorff Research Institute for Mathematics
Parent event: 
Vortex Seminar

Vortices and quantum Kirwan maps

Posted in
Speaker: 
Fabian Ziltener
Affiliation: 
KIAS, Seoul
Date: 
Tue, 2012-12-11 11:15 - 12:00
Location: 
Hausdorff Research Institute for Mathematics
Parent event: 
Vortex Seminar

Vortices and quantum Kirwan maps

Posted in
Speaker: 
Fabian Ziltener
Affiliation: 
KIAS, Seoul
Date: 
Tue, 2012-12-11 10:00 - 11:00
Location: 
Hausdorff Research Institute for Mathematics
Parent event: 
Vortex Seminar

The Vortex Seminar will consist of a minicourse in two parts (on Tuesday and Wednesday)

Dimension formulas for vector-valued Hilbert modular modular forms

Posted in
Speaker: 
Fredrik Strömberg
Affiliation: 
MPI
Date: 
Thu, 2012-12-20 10:45 - 11:45
Location: 
MPIM Lecture Hall
Parent event: 
Galois representations and pencils of Calabi-Yau motives
Parent event: 
Number theory lunch seminar

I will present some theoretical and computational aspects of dimension formulas for vector-valued Hilbert modular forms of integral and half-integral weight.

Obstructions to Dehn surgeries (Please note the date!)

Posted in
Speaker: 
Neil Hoffman
Date: 
Wed, 2012-12-12 15:00 - 16:00
Location: 
MPIM Lecture Hall
Parent event: 
MPI-Oberseminar

Lickorish and Wallace proved that all closed orientable 3-manifolds can be obtained by Dehn surgery along a link in S^3. Thurston observed that this proof gives rise to a connected graph that contains all closed orientable 3-manifolds, where every vertex of the graph corresponds to a 3-manifold and an edge corresponds to a Dehn surgery.

Course on The theory of $p$-local finite groups

Posted in
Speaker: 
Nora Seeliger
Date: 
Tue, 2012-12-11 10:00 - 12:00
Location: 
MPIM Seminar Room
Parent event: 
Course on The theory of $p-$local finite groups

h-cobordism theorem -- a more general cancellation theorem

Posted in
Speaker: 
M. Rodenhausen
Date: 
Mon, 2012-12-17 10:15 - 11:45
Location: 
MPIM Seminar Room
Parent event: 
IMPRS-seminar on Morse theory

h-cobordism theorem -- a first cancellation theorem

Posted in
Speaker: 
M. Rodenhausen
Date: 
Mon, 2012-12-10 10:15 - 11:45
Location: 
MPIM Seminar Room
Parent event: 
IMPRS-seminar on Morse theory

Adiabatic limit of Seifert fibrations, Dedekind sums, and the diffeomorphism type of certain 7-manifolds, II

Posted in
Speaker: 
Sebastian Goette
Affiliation: 
U Freiburg
Date: 
Mon, 2012-12-10 17:30 - 18:15
Location: 
MPIM Lecture Hall
Parent event: 
Geometric Topology Seminar

Adiabatic limit of Seifert fibrations, Dedekind sums, and the diffeomorphism type of certain 7-manifolds

Posted in
Speaker: 
Sebastian Goette
Affiliation: 
U Freiburg
Date: 
Mon, 2012-12-10 16:30 - 17:15
Location: 
MPIM Lecture Hall
Parent event: 
Geometric Topology Seminar

Eta invariants arise as a boundary correction term in the Atiyah-Patodi-Singer index theorem for manifolds with boundary. They also form the basic ingredients for several differential-topological invariants. I will explain the adiabatic limit formula for eta invariants on generalised Seifert fibrations and use it to determine the diffeomorphism types of certain cohomogeneity one manifolds, some of which admit positive sectional curvature.

The Kashiwara-Vergne conjecture and Drinfel'd associators III

Posted in
Speaker: 
C. Rossi
Affiliation: 
MPI
Date: 
Thu, 2012-12-06 12:00 - 13:30
Location: 
MPIM Lecture Hall
Parent event: 
IMPRS Minicourse
long format
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