# Events for 01/22/2021 from all calendars

## Seminar in Random Tensors

**Time: ** 11:00AM - 12:00PM

**Location: ** zoom

**Speaker: **Ming Yuan, Columbia U.

**Title: ***Low rank tensor completion*

**Abstract: **Many problems can be formulated as recovering a low-rank tensor from partial observations. Although an increasingly common task, tensor recovery remains a challenging problem because of the delicacy associated with the decomposition of higher order tensors. In this talk, I will describe results from our recent investigation of several common approaches to low rank tensor completion.

## Noncommutative Geometry Seminar

**Time: ** 1:00PM - 2:00PM

**Location: ** Zoom 951 5490 42

**Speaker: **Emil Prodan, Yeshiva University

**Title: ***Non-Commutative Geometry and Materials Science*

**Abstract: **Starting with the pioneering works of Jean Bellissard in the 1980’s,
Non-Commutative Geometry has emerged as one of sharpest tools in the arsenal of a theoretical materials scientist. Perhaps for this audience, the most important questions are why Non-Commutative Geometry and how much of it?
Using well understood examples, where specially designed materials display extraordinary behaviours in extreme conditions, I will try to convince the audience that one has to walk the entire sequence: algebra of observables → K-theory →pairing with cyclic cohomology → local index formula, plus one additional step which I call “pushing into the Sobolev.” Furthermore, among such extraordinary behaviours is a certain relation between the dynamics of degrees of freedominside the bulk and at the boundary of a sample, dubbed the bulk-boundary correspondence principle. It is captured by a certain extension of C*-algebras and, as such, KK-theory offers a natural framework and supplies the necessary tools to investigate such phenomena. If the time permits, I will also discuss recent efforts trying to steer these tools from their usual use of explaining observed behaviours towards the discovery of new dynamical behaviours in materials science.

**URL: ***Event link*