Talks Page – Global NCG Seminar

Romain Tessera

Geometry of lamplighters groups

In a joint work with Anthony Genevois, we classify up to quasi-isometry the class of lamplighter groups over one-ended finitely…

May 31, 2021

11:00

CEST

Organized by Asia-Pacific GNCG Seminar.

Steve Rosenberg

Wodzicki characteristic classes and diffeomorphism groups

The Wodzicki residue can be used to build Chern classes and Chern-Simons classes for infinite dimensional bundles with pseudodifferential…

May 24, 2021

11:00

CEST

Organized by Asia-Pacific GNCG Seminar.

Koen van den Dungen

Localisations and the Kasparov product in unbounded KK-theory

A well-known theorem by Connes and Skandalis provides sufficient conditions for finding the Kasparov product of two (bounded) Kasparov…

May 19, 2021

14:00

CEST

Organized by Europe GNCG Seminar.

Zhengwei Liu

Quantum Fourier Analysis

Quantum Fourier Analysis is a subject that combines an algebraic Fourier transform (pictorial in the case of subfactor theory) with…

May 17, 2021

11:00

CEST

Organized by Asia-Pacific GNCG Seminar.

Nikita Sopenko

Invertible states of quantum lattice spin systems and their invariants

Recently methods of quantum statistical mechanics have been fruitfully applied to the study of phases of quantum lattice systems…

May 14, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Karen Strung

Positive Line Bundles Over the Irreducible Quantum Flag Manifolds

Noncommutative Kähler structures were recently introduced by Ó Buachalla as a framework for studying noncommutative Kähler geometry on quantum…

May 12, 2021

14:00

CEST

Organized by Europe GNCG Seminar.

Edward McDonald

Semiclassical Weyl law and exact spectral asymptotics in noncommutative geometry

I discuss how a Tauberian theorem for singular values of noncommuting operators allows us to prove Weyl asymptotic formulas…

May 10, 2021

09:00

UTC

Organized by Asia-Pacific GNCG Seminar.

Zhizhang Xie

A relative index theorem for incomplete manifolds and Gromov’s conjectures on positive scalar curvature

In this talk, I will speak about my recent work on a relative index theorem for incomplete manifolds. As…

May 7, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Matthew Kennedy

Noncommutative convexity

Recently, Davidson and I introduced a new framework for noncommutative convexity and noncommutative function theory, along with a corresponding…

May 5, 2021

16:00

CEST

Organized by Europe GNCG Seminar.

Anna Skripka

Approximation of functions of unbounded operators

We will discuss recent advancements in approximation of functional calculus arising in problems of mathematical physics and noncommutative geometry….

April 30, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Adam Skalski

Translation invariant noncommutative Dirichlet forms

We shall discuss a class of noncommutative probabilistic evolutions, understood as Markov semigroups acting on von Neumann algebras and…

April 28, 2021

14:00

CEST

Organized by Europe GNCG Seminar.

Shin-ichi Oguni

A coarse Cartan-Hadamard theorem with application to the coarse Baum-Connes conjecture

We show a coarse version of the Cartan-Hadamard theorem,which states that proper coarsely convex spaces are coarsely homotopyequivalent to…

April 26, 2021

11:00

CEST

Organized by Asia-Pacific GNCG Seminar.

Ieke Moerdijk

An Introduction to Dendroidal Topology

Simplicial sets form a classical and well known tool for modelling topological spaces, and more recently topologically enriched categories…

April 23, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Sanaz Pooya

Higher Kazhdan projections, L²-Betti numbers, and the Coarse Baum-Connes conjecture

The Baum-Connes conjecture, if it holds for a certain group, provides topological tools to compute the K-theory of its…

April 21, 2021

14:00

CET

Organized by Europe GNCG Seminar.

Wilhelm Winter

Completely positive approximations revisited

I will try to put into context several well-known and one or two new facts around completely positive approximations of…

April 19, 2021

09:00

UTC

Organized by Asia-Pacific GNCG Seminar.

Yang Liu

Hypergeometric Functions and Heat Coefficients on Noncommutative Tori

As the counterpart of conformal geometry, modular geometry on noncommutative manifolds explores the basic notions such as metric and curvature…

April 16, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Paulo Carrillo Rouse

Chern assembly map for discrete groups and index theory

In this talk, I will report on joint work with B.L. WANG (ANU Canberra) et H. WANG (ECNU Shanghai). Given a discrete group $G$, I…

April 14, 2021

14:00

CEST

Organized by Europe GNCG Seminar.

Adam Rennie

The constructive Kasparov product

I will outline efforts to describe the Kasparov product of two unbounded Kasparov modules in terms of another unbounded…

April 12, 2021

09:00

UTC

Organized by Asia-Pacific GNCG Seminar.

Jean-Eric Pin

A noncommutative extension of Mahler’s interpolation theorem

Abstract. I will report on a result recently obtained with Christophe Reutenauer.Let p be a prime number. Mahler’s theorem…

April 9, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Francesco Fidaleo

Modular Spectral Triples arising from type III representations of the noncommutative torus

We discuss the explicit construction of non type $II_1$ representations and relative modular spectral triples of the noncommutative 2-torus…

April 7, 2021

14:00

CET

Organized by Europe GNCG Seminar.

Omar Mohsen

Inhomogeneous pseudo-differential calculus

Using techniques from noncommutative geometry, I will present a very general inhomogeneous pseudo-differential calculus which allows us to obtain…

April 5, 2021

11:00

CEST

Organized by Asia-Pacific GNCG Seminar.

Henrique Bursztyn

Relating Morita equivalence in algebra and geometry via deformation quantization.

The notion of Morita equivalence, native to ring theory, plays an important role in noncommutative geometry and has a…

April 2, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Adam Magee

Twisted real structures for spectral triples

Twisted real structures were introduced in 2016 as a generalisation of real structures for spectral triples which permit the…

March 31, 2021

14:00

CET

Organized by Europe GNCG Seminar.

Benoît Collins

Matrix models for non-commutative rational functions

We will report on arXiv:2103.05962, written in collaboration with Tobias Mai, Akihiro Miyagawa, Felix Parraud and Sheng Yin. Random matrix…

March 29, 2021

18:00

JST

Organized by Asia-Pacific GNCG Seminar.

Dan Voiculescu

Around the Quasicentral Modulus

The quasicentral modulus is a numerical invariant associated with a n-tuple of Hilbert space operators and a normed ideal of…

March 26, 2021

18:00

UTC

Organized by Americas GNCG Seminar.

Hermann Schulz-Baldes

Computational $K$-theory via the spectral localizer

Parings of $K$-theory with Fredholm modules given by Dirac operators can be computed numerically as the half-signature of a…

March 24, 2021

14:00

CET

Organized by Europe GNCG Seminar.

Stefaan Vaes

W*-rigidity paradigms for embeddings of II_1 factors

I will report on a recent joint work with Sorin Popa in which we undertake a systematic study of…

March 22, 2021

10:00

CET

Organized by Asia-Pacific GNCG Seminar.

Pere Ara

Crossed products and the Atiyah problem

It was shown by Austin in 2013 that the question by Atiyah about the rationality of $\ell^2$-Betti numbers has…

March 19, 2021

14:00

EDT

Organized by Americas GNCG Seminar.

Catherine Meusburger

Turaev-Viro State sum models with defects

We explain how to construct a Traev-Viro style state sum model with defects, where defect planes are labelled by…

March 17, 2021

14:00

CET

Organized by Europe GNCG Seminar.

Hao Guo

Scalar curvature, band width, and quantitative K-theory

I will discuss two connections between quantitative operator K-theory and scalar curvature, arising from recent work with Zhizhang Xie…

March 15, 2021

20:00

GMT+11

Organized by Asia-Pacific GNCG Seminar.

Asghar Ghorbanpour

Scalar curvature of functional metrics on noncommutative tori

In recent years, the investigation of geometries of noncommutative tori has attracted attention from both mathematics and physics. In…

March 12, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Paolo Piazza

Surgery sequences and higher invariants of Dirac operators

The analysis of the signature operator and of the spin-Dirac operator on a $\Gamma$-Galois covering of a smooth compact…

March 10, 2021

14:00

CET

Organized by Europe GNCG Seminar.

Shilin Yu

Deformation quantization of coadjoint orbits

The “coadjoint orbit method” philosophy of Kirillov and Kostant suggests that there is a close connection between the unitary…

March 8, 2021

17:00

GMT+8

Organized by Asia-Pacific GNCG Seminar.

Claire Debord

Cyclic subsets, groupoids and VB-groupoids

In this talk, after recalling basic facts on groupoids, we will see that the structure of a groupoid G…

March 5, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Kristin Courtney

Generalized inductive limits with asymptotically order zero maps

In the 1990s, Blackadar and Kirchberg introduced NF algebras, which arise as limits of inductive systems where the connecting…

March 2, 2021

15:00

CET

Organized by Europe GNCG Seminar.

Joachim Cuntz

The algebraic approach to KK-theory

Kasparov’s KK-theory which is based on so called Kasparov-modules can be described much more algebraically using universal extensions and classifying maps…

March 1, 2021

10:00

CET

Organized by Asia-Pacific GNCG Seminar.

Alcides Buss

Amenable actions of groups on C*-algebras

In this lecture I will explain recent developments in the theory of amenability for actions of groups on C*-algebras…

February 26, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Xiang Tang

Cyclic Cocycles for Proper Lie Group Actions

In this talk, we will report our exploration of cyclic cohomology of the Harish-Chandra Schwartz algebra of a connected…

February 23, 2021

15:00

CET

Organized by Europe GNCG Seminar.

Eckhard Meinrenken

Differential Geometry of Weightings

The idea of assigning weights to local coordinate functions appears in many areas of mathematics, such as singularity theory,…

February 19, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Sergiy Neshveyev

Crystallization of C$^*$-algebras

Given a C$^*$-algebra $A$ with an almost periodic time evolution we define a new C$^*$-algebra $A_c$ whose states parameterize…

February 16, 2021

15:00

CET

Organized by Europe GNCG Seminar.

Henry Yuen

Testing low-degree polynomials in the noncommutative setting

In low-degree testing the following question is considered: given a multivariate function over a finite field, if a sufficiently…

February 12, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Sylvie Paycha

A Galois group on meromorphic germs and locality evaluators

Meromorphic germs (say at zero) in several variables with linear poles naturally arise in the context of renormalisation, which…

February 9, 2021

15:00

CET

Organized by Europe GNCG Seminar.

Jens Hemelaer

Toposes in arithmetic noncommutative geometry

We give an introduction to topos theory from a geometric point of view, focusing on toposes that arise from…

February 5, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Lisa Glaser

Truncated spectral triples on the computer

When describing a Riemannian geometry as a spectral triple, the algebra of functions on the geometry is infinite. But…

February 2, 2021

15:00

CET

Organized by Europe GNCG Seminar.

Pierre Albin

The sub-Riemannian limit of a contact manifold

Contact manifolds, which arise naturally in mechanics, dynamics, and geometry, carry natural Riemannian and sub-Riemannian structures and it was…

January 29, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Andreas Thom

Asymptotics of Cheeger constants and unitarisability of groups

Given a group Γ, we establish a connection between the unitarisability of its uniformly bounded representations and the asymptotic behaviour…

January 26, 2021

16:00

CET

Organized by Europe GNCG Seminar.

Emil Prodan

Non-Commutative Geometry and Materials Science

Starting with the pioneering works of Jean Bellissard in the 1980’s,Non-Commutative Geometry has emerged as one of sharpest tools…

January 22, 2021

14:00

EST

Organized by Americas GNCG Seminar.

Francesco D’Andrea

The K-theory of quantized CW-complexes

If a quantum space X can be obtained by “gluing” two subspaces Y and Z, there is a Mayer-Vietoris…

January 19, 2021

15:00

CET

Organized by Europe GNCG Seminar.

Elmar Schrohe

Index Theory for Fourier Integral Operators and the Connes-Moscovici Local Index Formulae

The index theory for operator algebras generated by pseudodifferential operators and Fourier integral operators, more specifically Lie groups of…

April 29, 2020

19:00

UTC

Organized by Americas GNCG Seminar.

Jonathan Rosenberg

Positive scalar curvature on a class of spin pseudomanifolds

April 22, 2020

19:00

UTC

Organized by Americas GNCG Seminar.

All talks