Wed, March 4, 2020
Public Access Category: All |
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- Time:
- 11:00am-12:30pm
- Location:
- Ramanujan Hall, Department of Mathematics
- Description:
- Combinatorics seminar.
Speaker: Subhajit Ghosh.
Affiliation: IISc Bengaluru.
Date and Time: Wednesday 04 March, 11:00 am - 12:30 pm.
Venue: Ramanujan Hall, Department of Mathematics.
Title: Total variation cutoff for the flip-transpose top with random shuffle.
Abstract:
Abstract. We consider a random walk on the hyperoctahedral
group Bn generated by the signed permutations of the forms (i, n)
and (−i, n) for 1 ≤ i ≤ n. We call this the flip-transpose top
with random shuffle on Bn. We find the spectrum of the transition
probability matrix for this shuffle. We obtain the sharp mixing
time for this shuffle by proving total variation cutoff phenomenon
with cutoff time n log n.
- Time:
- 2:00pm-3:00pm
- Location:
- Ramanujan Hall, Department of Mathematics
- Description:
- Analysis seminar.
Speaker: Bata Krishna Das.
Affiliation: IIT Bombay.
Date and Time: Wednesday 04 March, 02:00 pm - 03:00 pm.
Venue: Ramanujan Hall, Department of Mathematics.
Title: Model of operators and their characteristic functions.
Abstract: In this talk, using Sz.-Nagy and Foias isometric dilation, we will de-scribe functional models of a class of operators. This will further lead us to define their characteristic functions which are complete unitary in- variants. We will also discuss the connection between invariant subspace problem and factorization of characteristic functions. If time permits we will see a recently developed multivariate analogue of these notions.
- Time:
- 4:00pm-5:00pm
- Location:
- Ramanujan Hall, Department of Mathematics
- Description:
- Mathematics Colloquium.
Speaker: Siddhartha Bhattacharya.
Affiliation: TIFR Mumbai.
Date and Time: Wednesday 04 March, 04:00 pm - 05:00 pm.
Venue: Ramanujan Hall, Department of Mathematics.
Title: Translational tilings of the plane.
Abstract: A set $A\subset {\mathbb R}^2$ is said to be a translational
tile if ${\mathbb R}^2$ can be expressed as a disjoint union of
translated copies of $A$. In this talk we will discuss the connection
between such tiles and measure preserving dynamical systems. We will show
that if the underlying set $A$ satisfies a certain regularity condition
then the question whether $A$ tiles the plane is decidable.