April 2017
Public Access Category: All |

- Time:
- 3:30pm
- Location:
- Room 114
- Description:
- Title: Some aspects of open de Rham spaces

Abstract: Open de Rham spaces refer to certain moduli spaces of meromorphic connections on the projective line. I will discuss certain aspects of these, namely their relation to quiver varieties, the existence of hyperkaehler metrics, and the computation of their E-polynomials.

- Time:
- 11:00am - 12:00pm
- Location:
- Ramanujan Hall
- Description:
- Title: Every graph is (2,3)-choosable

Abstract:

A total weighting of a graph G is a mapping f which assigns to each element

z ∈ V (G)∪E(G) a real number f(z) as its weight. The vertex sum of v

with respect

to f is the sum of weight of v and weights of edges adjacent to v. A

total weighting is proper if vertex sums of adjacent vertices are

distinct. A (k, k')-list assignment is a mapping L which assigns to

each

vertex v a set L(v) of k permissible weights, and assigns to each edge

e a set L(e) of k'

permissible weights. We say G is (k, k')-choosable if for any (k,

k')-list assignment L, there is a proper total weighting f of G with

f(z) ∈ L(z) for each z ∈ V (G)∪E(G).

It was conjectured by Wong and Zhu that every graph is (2,

2)-choosable and every

graph with no isolated edge is (1, 3)-choosable. We will see a proof

of the statement in the title, due to Wong and Zhu.

- Time:
- 3:30pm - 5:00pm
- Location:
- Room 113
- Description:
- Title: Flows on homogeneous spaces

Abstract: We shall continue the discussion on the results of Marina Ratner on unipotent flows.

Thanks

- Time:
- 4:00pm - 5:00pm
- Location:
- Ramanujan Hall
- Description:
- Title:

Skew Products Over The Irrational Rotation, The Central Limit Theorem And RATs

Abstract:

Let f be a step function on the circle with zero mean and rational discontinuities while alpha is a quadratic irrational. The point-wise ergodic theorem tells us that the ergodic sums, f(x)+f(x+alpha)+...+f(x+(n-1)alpha) is o(n) for almost every x but says nothing about its deviations from zero, that is, its discrepancy; the study of these deviations naturally draws us to the study of ergodic transformations on infinite measure spaces, viz., skew products over irrational rotations. In this talk, after a brief introduction to these terms, we will learn how the temporal statistics of the ergodic sums for x=0 can be studied via random affine transformations (RATs) leading to a central limit theorem and other fine properties like the visit times to a neighbourhood of 0 vis-à-vis bounded rational ergodicity (all of course time permitting). This is reporting on joint work with Jon Aaronson and Michael Bromberg.

- Time:
- 11:00am - 12:00pm
- Location:
- Ramanujan Hall
- Description:
- Title: On a Poset of Trees I and II by Peter Csikvari

Abstract: http://www.math.iitb.ac.in/~seminar/combinatorics/mukesh-kumar-nagar-12-april-17.pdf

- Time:
- 4:00pm - 5:00pm
- Location:
- Ramanujan Hall
- Description:
- Speaker: Prof Debasis Kundu, IIT Kanpur

Title: Analyzing Periodic Data: Statistical Perspectives

Abstract: We observe periodic phenomena everyday in our lives. The daily temperature of Delhi or the number of tourists visiting the famous Taj Mahal or the ECG data of a normal human being, clearly follow periodic nature. Sometimes, the observations may not be exactly periodic

due to different reasons, but they may be nearly periodic. The received data is usually disturbed by various factors. Due to random nature of the data, statistical techniques play important roles in analyzing the data. Statistics is also used in the formulation of appropriate models to describe the behavior of the system, development of an appropriate technique for estimation of model parameters, and the assessment of model performances. In this talk we will discuss different techniques which we have developed for the last twenty five years for analyzing periodic data, other than the standard Fourier analysis.

- Time:
- 11:00am - 12:00pm
- Location:
- Ramanujan Hall
- Description:
- Title: On a Poset of Trees I and II by Peter Csikvari

Abstract: http://www.math.iitb.ac.in/~seminar/combinatorics/mukesh-kumar-nagar-12-april-17.pdf

- Time:
- 2:30pm
- Location:
- Ramanujan Hall
- Description:
- Title: Extensions of mod p smooth representations of p-adic groups

Abstract: In this talk I will explain some results on the extensions of mod-p characters of affine pro-p Iwahori–Hecke algebras. As a preliminary application we compute the degree one extensions of smooth representations of SL(2,Q_p). These calculations also reveal interesting phenomenon on Iwahori subgroup cohomology of smooth representations. If time permits I will explain how these extensions can be related to local Galois representations.

- Time:
- 10:30am
- Location:
- Room 215
- Description:
- Title: Complex oriented cohomology Theories

I will talk about formal group laws and their relation to complex oriented cohomology theories. In the end I will state Landweber exact functor theorem.

- Time:
- 2:30pm
- Location:
- Ramanujan Hall
- Description:
- Title: Analytic properties of multiple zeta functions

The speaker is a postdoctoral candidate. Faculty in the relevant area (Number Theory) are urged to attend this talk and give their valuable feedback.

- Time:
- 3:00pm
- Location:
- Room 215
- Description:
- Title: Construction of non-arithmetic lattices in hyperbolic space.