Termine im Sommersemester 2017:

15.05.2017

• Simon Schmidt
• Quantum automorphisms of graph C^*-algebras
• In this talk we present quantum automorphism groups of graphs. Those are quantum groups that generalize classical automorphism groups and there are actually two definitions of them. Our main result is that one of the definitions gives rise to the quantum symmetry group of the graph C^*-algebra. Therefore, one can think of the quantum symmetries of the graph C^*-algebra as the quantum automorphisms of the underlying graph.

29.05.2017

• Ricardo Schnur
• Title: The Connes embedding property for free orthogonal quantum groups
• In this talk we show that for $N \geq 4$ the von Neumann algebra associated to the free orthogonal quantum group $O_N^+$ possesses the Connes embedding property. That is to say, it can be embedded into an ultrapower of the hyperfinite type $\text{\normalfont{II}}_1$ factor by a free ultrafilter. The main tool for this will be the notion of a quantum group being topologically generated by two of its quantum subgroups as introduced by Brannan, Collins and Vergnioux.

12.06.2017

• Michael Hartz
• Achtung, dieser Vortrag wird ausnahmsweise schon um 14 Uhr und in Hö,rsaal IV stattfinden.
• A multiplier functional calculus
• A classical result of Sz.-Nagy and Foias shows that every contraction $T$ on a Hilbert space without unitary summand admits an $H^\infty$-functional calculus, that is, one can make sense of $f(T)$ for every bounded analytic function $f$ in the unit disc. I will talk about a generalization of this result, which applies to tuples of commuting operators and multiplier algebras of a large class of Hilbert function spaces on the unit ball. In particular, this extends a theorem of Eschmeier, as well as a recent result of Clou^atre and Davidson for commuting row contractions. This is joint work with Kelly Bickel and John McCarthy.

10.07.2017

• Sebastian Toth
• Ein Satz über Rand-Darstellungen von Arveson

17.07.2017

• Manuel Kany
• wird noch angekündigt

24.07.2017

• Evelyn Weber
• Eindeutigkeit der Normtopologie auf halbeinfachen Banachalgebren.