
Date Time 
Location  Speaker 
Title – click for abstract 

01/16 2:00pm 
BLOC 628 
Jianchao Wu Pennsylvania State University 
The Novikov conjecture, the group of volume preserving diffeomorphisms, and HilbertHadamard spaces
The Novikov conjecture is a central problem in manifold topology. Noncommutative geometry provides a potent approach to tackle this conjecture. Using C*algebraic and Ktheoretic tools, we prove that the Novikov conjecture holds for any discrete group admitting an isometric and metrically proper action on an admissible HilbertHadamard space, which is an infinitedimensional analogue of complete simply connected nonpositively curved Riemannian manifolds. In particular, these groups include geometrically discrete subgroups of the group of volume preserving diffeomorphisms of a compact smooth manifold with a fixed volume form. This is joint work with Sherry Gong and Guoliang Yu. 

02/13 2:00pm 
BLOC 628 
Clément Dell'Aiera University of Hawaii 
Decomposition complexity, a dynamical approach
Finite Decomposition Complexity was introduced by E. Guentner, R. Tessera and G. Yu as a generalization of finite asymptotic dimension. We will investigate how it can be suitably defined for topological actions of discrete groups (more generally topological groupoids), and present some applications in Operator Algebras and Ktheory, e.g. one can obtain the Künneth formula for the uniform Roe algebra of some groups which are not coarsely embeddable into Hilbert space. Other applications include the BaumConnes conjecture. 

02/20 2:00pm 
BLOC 628 
Qin Wang East China Normal University 
The coarse Novikov conjecture and Banach spaces with property (H)
The coarse Novikov conjecture is a geometric analogue of the strong Novikov conjecture,
while property (H) is a geometric condition for Banach spaces introduced by G. Kasparov and G. Yu in studying the strong Novikov conjecture. In this talk, I will discuss applications of coarse embeddings or fibred coarse embeddings of metric spaces into Banach spaces with property (H) to the coarse Novikov conjecture. 

03/06 2:00pm 
BLOC 628 
Hao Guo Texas A&M University 
A Lichnerowicz vanishing theorem for the maximal roe algebra
Let M be a complete spin Riemannian manifold. Then the Dirac operator on M has an index taking values in the Ktheory of the maximal Roe algebra. One of the basic properties one would like to have for this index is that it vanishes when the M has uniformly positive scalar curvature. But as distinct from the setting of the reduced Roe algebra, one cannot directly apply a functional calculus argument on the maximal Roe algebra to show this vanishing. In this talk we outline the steps to a proof of this fact using a uniform version of the maximal Roe algebra. This is joint work with Zhizhang Xie and Guoliang Yu. 

03/20 2:00pm 
BLOC 628 
Zhuang Niu University of Wyoming 
[Colloquium] Comparison radius and mean dimension
Comparison radius of a C*algebra was introduced by Toms to measure the regularity of a C*algebra, and it can be regarded as a C*version of dimension growth. Mean topological dimension was introduced by Gromov and developed by Lindenstrauss and Weiss, and it is an invariant for topological dynamical systems which measures dimension growth along orbits. In the talk, I will discuss some estimations of the comparison radius of the crossed product C*algebra in terms of the mean dimension of the dynamical system.


03/27 2:00pm 
BLOC 628 
Rudolf Zeidler University of Münster 
Slant products on the analytic structure group via the stable Higson corona
We show injectivitiy of certain exterior product maps on the Ktheory of the Roe algebra and the analytic structure group by a partial pairing (or "slant product") with the Ktheory of the stable Higson corona. We will explore applications in primary and secondary index theory, in particular to positive scalar curvature. This is ongoing joint work with Alexander Engel and Christopher Wulff. 

04/03 2:00pm 
BLOC 628 
Stuart White University of Glasgow 
Simple amenable C*algebras
I’ll discuss recent developments in the structure and classification of simple amenable C*algebras: how do we recognise C*algebras which should be classified, and once we’ve found them, how should they be classified? New results will be based on joint work with Castillejos, Evington, Tikuisis and Winter, and with Carrion, Gabe, Schafhauser and Tikuisis.
