Oberseminare und sonstige Vorträge

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weckerm

Giles Gardam: The geometry of the word problem (Seminar Geometric Group Theory)

Mittwoch, 24.04.2019 14:15 im Raum SRZ 217
Mathematik und Informatik



Angelegt am Dienstag, 23.04.2019 08:26 von weckerm
Geändert am Mittwoch, 24.04.2019 11:25 von wuebbel
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Oberseminare und sonstige Vorträge
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boeckena

Rudolf Zeidler (WWU Münster):Coarse (co-)assembly and the analytic structure group. (Oberseminar Topologie)

Montag, 29.04.2019 14:00 im Raum M4
Mathematik und Informatik



Angelegt am Dienstag, 26.03.2019 11:21 von boeckena
Geändert am Dienstag, 16.04.2019 08:42 von boeckena
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Oberseminare und sonstige Vorträge
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shupp_01

Oberseminar Differentialgeometrie: Marco Freibert (Universität Kiel): The spinor flow on homogeneous manifolds

Montag, 29.04.2019 16:15 im Raum SR4
Mathematik und Informatik

The spinor flow of Ammann-Weiß-Witt on a compact manifolds $M$ is a geometric flow equation for pairs $(g,\phi)$ of a Riemannian metric $g$ and a unit spinor field $\phi$ whose critical points in dimensions greater or equal to 3 are Ricci-flat Riemannian manifolds $(M,g)$ of special holonomy together with a parallel spinor field $\phi$. In my talk, I will give an introduction to this flow in the general setting and show how one may define a homogeneous version on compact homogeneous manifolds, which may also be extended to non-compact homogeneous manifolds. Moreover, I will present some results on the long-time behaviour of the usual and a volume-normalized version of the homogeneous spinor flow on specific homogeneous manifolds.



Angelegt am Donnerstag, 21.02.2019 13:22 von shupp_01
Geändert am Montag, 15.04.2019 15:43 von shupp_01
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Oberseminare und sonstige Vorträge
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folkeri

Oberseminar p-adische Arithmetik: Maike Frantzen: Singular support and ind-coherent sheaves

Dienstag, 30.04.2019 16:15 im Raum SR 1C
Mathematik und Informatik



Angelegt am Donnerstag, 18.04.2019 13:44 von folkeri
Geändert am Donnerstag, 18.04.2019 13:59 von folkeri
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Oberseminare und sonstige Vorträge
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elke

Ebrahim Sawei (Saskatoon, z.Zt. Warschau): Exotic C*-algebras of geometric groups. Oberseminar C*-Algebren.

Dienstag, 16.04.2019 15:15
Mathematik und Informatik

We consider a new class of potentially exotic group C*-algebras $C^*(\text{PF}_{p}^*(G))$ for a locally compact group $G$, and its connection with the class of potentially exotic group C*-algebras $C^*_{L^p}(G)$ introduced by Brown and Guentner \cite{BG}. Surprisingly, these two classes of C*-algebras are intimately related. By exploiting this connection, we show $C^*_{L^p}(G)=C^*(\text{PF}_{p}^*(G))$ for $p\in (2,\infty)$, and the C*-algebras $C^*_{L^p}(G)$ are pairwise distinct for $p\in (2,\infty)$ when $G$ belongs to a large class of nonamenable groups possessing the Haagerup property and either the rapid decay property or Kunze-Stein phenomenon by characterizing the positive definite functions that extend to positive linear functionals of $C^*_{L^p}(G)$ and $C^*(\text{PF}_{p}^*(G))$. This greatly generalizes earlier results of Okayasu \cite{Okay} and Wiersma on the pairwise distinctness of $C^*_{L^p}(G)$ for $20$ (recall $A_\pi\subseteq B_\pi$). Here $A_\pi$ and $B_\pi$ are the closed span of coefficients of $\pi$ in the norm and $w^*$-topology of the Fourier-Stieljes algebra $B(G)=C^*(G)^*$, respectively. In particular, we have $A_\pi\subseteq B_\pi$.\\ This is based on a joint work with M. Wiersma.



Angelegt am Freitag, 15.03.2019 10:47 von elke
Geändert am Freitag, 15.03.2019 10:47 von elke
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Oberseminare und sonstige Vorträge
Veranstaltungen am Mathematischen Institut
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boeckena

Jan-Bernhard Kordaß (Karlsruher Institut für Technologie): t.b.a. (Oberseminar Topologie)

Montag, 06.05.2019 14:00 im Raum ??
Mathematik und Informatik



Angelegt am Mittwoch, 20.03.2019 08:38 von boeckena
Geändert am Mittwoch, 20.03.2019 08:38 von boeckena
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Oberseminare und sonstige Vorträge
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shupp_01

Oberseminar Differentialgeometrie: Miles Simon (Universität Magdeburg): On the regularity of Ricci flows coming out of metric spaces

Montag, 06.05.2019 16:15 im Raum SR4
Mathematik und Informatik

Abstract: We consider solutions to Ricci flow defined on manifolds M for a time interval (0,T) whose Ricci curvature is bounded uniformly in time from below, and for which the norm of the full curvature tensor at time t is bounded by c/t for some fixed constant c>1 for all t in (0,T). From previous works, it is known that if the solution is complete for all times t>0, then there is a limit metric space (M,d_0), as time t approaches zero. We show : if there is a region V on which (V,d_0) is *smooth*, then the solution can be extended smoothly to time zero on V.



Angelegt am Donnerstag, 21.02.2019 13:23 von shupp_01
Geändert am Donnerstag, 18.04.2019 10:21 von shupp_01
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Oberseminare und sonstige Vorträge
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