The mathematical colloquium of the HHU Düsseldorf takes place
Fridays
16:45 - 17:45 in room 25.22 HS 5H.
Before the colloquium from 16:15 everybody is invited for tea, coffee and cookies in 25.22.00.53.
31.10.2014 |
Thorsten Weist
(Universität Düsseldorf).
Abstract. |
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Kombinatorische Geometrie in der Darstellungstheorie.
Abstract: Kombiniert man eine Formel von Manschot-Pioline-Sen mit der sogenannten Lokalisierungsmethode, so ist die Eulercharakteristik von Modulräumen stabiler Köcherdarstellungen bereits durch die Anzahl gewisser orientierter Bäume gegeben. Die sogenannte GW/Kronecker-Korrespondenz zwischen der Eulercharakteristik dieser Modulräume und gewissen Gromov-Witten-Invarianten impliziert deshalb eine direkte Beziehung zwischen der Anzahl dieser Bäume und der Anzahl bestimmter tropischer Kurven.
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21.11.2014 |
Werner Lütkebohmert
(Universität Ulm). |
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Polarisierung von Jacobi-Varietäten. |
28.11.2014 |
Christopher Voll
(Universitaet Bielefeld).
Abstract. |
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Representation zeta functions of groups.
Abstract: A group is called representation rigid if it has only finitely many
irreducible complex representations of each finite dimension. If the
numbers of such representations of a rigid group grow slowly,
i.e. polynomially, we may consider them as the coefficients of a
Dirichlet generating function, called the group's representation zeta
function.
In my talk I will discuss some aspects of the theory of representation
zeta functions of arithmetic groups. These zeta functions share a
number of features with their classical predecessors in number theory
and geometry. Often, for instance, they are Euler products, indexed by
the places of a number field, whose non-archimedean factors are
rational functions.
As I will explain, the study of these Euler factors and the analytic
properties of their products calls for methods which are quite
distinct from those used in more classical contexts. I will discuss a
range of tools -- ranging from (p-adic) Lie theory, geometric
representation theory, to p-adic integration and model theory -- which
were developed to study the Euler factors representation zeta
functions of arithmetic groups, and their local and global properties.
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05.12.2014 |
Olivier Debarre
(ENS Paris & Paris 7).
Abstract. |
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Around cubic hypersurfaces. Text of the talk. |
09.01.2015 |
Michael Langenbruch
(Universität Oldenburg).
Abstract. |
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Interpolation holomorpher Funktionen und Surjektivität Eulerscher partieller Differential-operatoren. |
23.01.2015 |
Balint Farkas
(Universität Wuppetal).
Abstract. |
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Ist die identische Abbildung IR --> IR die Summe periodischer Funktionen?
Im Vortrag wird diese klassische Fragestellung verallgemeinert und beantwortet, und ihr Zusammenhang mit harmonischer Analysis, Algebra, und Funktionalanalysis diskutiert.
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30.01.2015 |
Kai-Uwe Bux
(Universität Bielefeld).
Abstract. |
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Finiteness properties of (arithmetic) groups, a survey.
Groups are meant to act. Understanding a group via
its actions is the underlying idea of different areas such as
representation theory and geometric group theory. Here, I shall
focus on group actions on topological and metric spaces. We
will see how such actions can provide finite generating sets
for the group and hence yield a proof that the group is finitely
generated. These ideas can be pushed to finite presentability
and so called "higher finiteness properties". I will dicuss many
examples, mainly from arithmetic groups.
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