Seminars - Page 3

Zahra Afsar (The University of Sydney, Australia) will give a talk titled: C*-algebras of self-similar actions of groupoids on higher-rank graphs and their equilibrium states

Erik Habbestad (UiO): Asymptotic representation theory of the infinite quantum symmetric group

Floris Elzinga (UiO): Free Monotone Transport for q-Gaussians

Nathan Brownlowe (The University of Sydney, Australia) will give a talk titled: Reconstructing directed graphs from their Toeplitz algebras.

Kenny De Commer (Vrije Universiteit Brussel, Belgium) will give a talk titled: Spectral *-algebras and quantum group actions

Petter Nyland (NTNU) will give a talk titled: Matui’s Conjectures for Étale Groupoids.

Andrey Mudrov (University of Leicester, United Kingdom) will give a talk titled: Pseudo-parabolic categories over HP_qⁿ

Franz Fuchs (SINTEF) will give a talk with title: 

Quantum Computing and Quantum Supremacy

Ulrik Enstad (University of Oslo) will give a talk titled: Heisenberg modules and the existence (or lack thereof) of Gabor frames

Seung-Hyeok Kye (Seoul National University, Korea) will give a talk titled: Indecomposable exposed multi-linear maps and separable states with unique decomposition.

Roberto Conti (Sapienza University of Rome, Italy) will give a talk titled: Endomorphisms of simple C*-algebras generated by isometries.

Sanaz Pooya (Stockholm), Sweden, will give a talk titled: On the Baum–Connes assembly map for certain semi-direct products.

Sven Raum (Stockholm), Sweden, will give a talk with title: C*-superrigidity of 2-step nilpotent groups

Camila Fabre Sehnem (Florianopolis), Brasil, will give a talk with title :

On $C^*$-algebras associated to product systems

An abstract of the talk is available here.

Prof. Masaki Izumi, Kyoto University, Japan, will give a talk with title:

The classification of poly-Z group actions on Kirchberg algebras

Abstract: We completely classify outer actions of a poly-Z group G on any Kirchberg algebra A in terms of a principal Aut(A x K)-bundle over the classifying space BG. This is joint work with Hiroki Matui.

Becky Armstrong, University of Sydney, Australia, will give a talk with title:

Simple graph algebras

Abstract: Since their introduction twenty years ago, C*-algebras associated to directed graphs have become a popular tool for investigating various classes of C*-algebras, because analytical properties of these C*-algebras depend on much simpler combinatorial properties of the underlying graphs. One such analytical property is simplicity, which plays a fundamental role in the classification program for C*-algebras. In this talk I will first recall the characterisation of simplicity for directed graph C*-algebras. I will then describe the results of my PhD research, in which I characterise simplicity of twisted C*-algebras of topological higher-rank graphs in terms of the underlying graphical and cohomological data. These C*-algebras are constructed using groupoid techniques for the purpose of this simplicity characterisation, but I will also briefly describe two product-system models for twisted C*-algebras of topological higher-rank graphs. (This is joint work with my PhD supervisors, Nathan Brownlowe and Aidan Sims.)

Kurusch Ebrahimi-Fard (NTNU) will give a talk with title: Moment-cumulant relations in noncommutative probability and shuffle-exponentials

Abstract: In this talk we consider monotone, free, and boolean moment-cumulant relations from the shuffle algebra viewpoint. Cumulants are described as infinitesimal characters over a particular combinatorial Hopf algebra, which is neither commutative nor cocommutative. As a result the moment-cumulant relations can be encoded in terms of shuffle and half-shuffle exponentials. These shuffle exponentials and the corresponding logarithms permit to express monotone, free, and boolean cumulants in terms of each other using the pre-Lie Magnus expansion. If time permits we will revisit additive convolution in monotone, free and boolean probability and related aspects. Based on joint work with F. Patras (CNRS).

Zahra Afsar (University of Wollongong, Australia) will give a talk with title: Nica-Toeplitz-algebras of *-commuting local homeomorphisms and equilibrium states

Abstract: Given a family of *-commuting local homeomorphisms on a compact space, we can build a compactly aligned product system of Hilbert bimodules. The product system has a Nica-Toeplitz algebra which carries a gauge action of a higher-dimensional torus, and there are many possible dynamics obtained by composing with different embeddings of the real line in this torus. In this work, which is a joint work with Prof. Astrid an Huef and Prof. Iain Raeburn, I will talk about the equilibrium states of these dynamics. If time allows, I will also provide some examples from higher rank graph theory and reconcile our results with those existing ones.

Elizabeth Gillaspy from the University of Montana at Missoula, USA, will give a talk with title " Finite decomposition rank and strong quasidiagonality for virtually nilpotent groups "

Abstract: In joint work with Caleb Eckhardt and Paul McKenney, we show that the C*-algebras of discrete, finitely generated, virtually nilpotent groups G are strongly quasidiagonal and have finite decomposition rank. Thus, the only remaining step required to show that primitive quotients of such virtually nilpotent groups G are classified by their Elliott invariant is to check that these C*-algebras satisfy the UCT. Our proof of finite decomposition rank relies on a careful analysis of the relationship between primitive ideals of C*(G) and those of C*(N), where N is a finite-index normal subgroup of G. In the case when N is also nilpotent, we obtain a decomposition of C*(G) as a continuous field of twisted crossed products, which enables us to prove finite decomposition rank of C*(G) by analyzing the decomposition rank of the fibers.  

Antoine Julien, Universitetet i Nord, will give a talk with title:  Rieffel-type projections in higher-dimensional rotation algebras

Abstract: Rieffel first built a non-trivial projection in the rotation algebra by considering a certain C*-module over this algebra, and exploiting the Morita equivalence which it implements. In this talk, I will present how it is possible to extend these ideas to construct explicitly projections in higher-dimensional noncommutative tori. Precisely, our techniques can be applied to the NC tori which are associated with an R^d-flow on a 2d-torus, or equivalently which are given by the crossed product of C(T^d) by Z^d. I will also hint on how this result can be interpreted as constructing Gabor atoms associated with some lattices in the time-frequency space R^{2d}. This is a joint work with Franz Luef (NTNU).