Department of

# Mathematics

Seminar Calendar
for events the day of Monday, November 3, 2014.

.
events for the
events containing

Questions regarding events or the calendar should be directed to Tori Corkery.
     October 2014          November 2014          December 2014
Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa   Su Mo Tu We Th Fr Sa
1  2  3  4                      1       1  2  3  4  5  6
5  6  7  8  9 10 11    2  3  4  5  6  7  8    7  8  9 10 11 12 13
12 13 14 15 16 17 18    9 10 11 12 13 14 15   14 15 16 17 18 19 20
19 20 21 22 23 24 25   16 17 18 19 20 21 22   21 22 23 24 25 26 27
26 27 28 29 30 31      23 24 25 26 27 28 29   28 29 30 31
30


Monday, November 3, 2014

2:30 pm in 443 Altgeld Hall,Monday, November 3, 2014

#### Topology in Networks and Signal Processing

###### Harish Chintakunta (UIUC ECE)

Abstract: I will talk about a few applications where topological features play an important role, including emphasis on computational aspects. In sensor networks, I will show how combinatorial Laplacians can be effectively used to find coverage holes and compute persistence of homological features to improve robustness. I will then discuss the relation between restricted Delaunay triangulation and alpha complexes, and its implications in networks. I think Topology will play a major role in signal processing and social networks, and we are beginning to see these connections. In signal processing, the entry point for Topology is the delay embedding, where a signal is converted into a point cloud. I will talk about about a simple application of detecting wheezes in breathing signals using this approach, and then share my view of future of topology (and geometry) in signal processing. In social networks, I will present some of our recent findings on how topology influences the core periphery decomposition of a network, and helps in detecting communities.

3:00 pm in 341 Altgeld Hall,Monday, November 3, 2014

#### Poisson geometry and Lie theory of vector bundles

###### Henrique Bursztyn (IMPA)

Abstract: In this talk I will discuss vector bundles in the realm of Lie groupoids (resp. Lie algebroids), known as VB-groupoids (resp. VB-algebroids). Just as Lie groupoids are common generalizations of manifolds and Lie groups (often thought of as models for singular spaces), VB-groupoids encompass vector bundles and linear representations (and can be thought of as categorified'' vector bundles over singular spaces). I will explain the Lie theory relating VB-groupoids and VB-algebroids, including examples and applications. Poisson structures enter the picture as objects dual to Lie algebroids, and I will point out the role of this dual viewpoint in our results. This is joint work with A. Cabrera and M. del Hoyo.

4:00 pm in 243 Altgeld Hall,Monday, November 3, 2014

#### Snaith's Cheshire Cat

###### Sarah Yeakel (UIUC Math)

Abstract: 'Twill be brillig when we'll fall down a rabbit hole into the wonderland of stable splittings, first meeting various classical constructions of James and Boardman. We may encounter a spectral sequence as we investigate some exciting proofs from the 70s. If we're not too late, some slithy Goodwillie calculus may appear. We hope it will not be complete nonsense.

5:00 pm in Altgeld Hall,Monday, November 3, 2014