16-05-2018 |
Mathematics Colloquium |
Groups with norms: a PolyMath adventure
Consider the following three properties of a general group G:
(1) Algebra: G is abelian and torsion-free.
(2) Analysis: G is a metric space that admits a "norm", namely, a
translation-invariant metric d(.,.) satisfying: d(1,g^n) = |n| d(1,g) for
all g in G and integers n.
(3) Geometry: G admits a length function with "saturated" subadditivity
for equal arguments: l(g^2) = 2 l(g) for all g in G.
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26-04-2018 |
Dr. Debayan Maity, Affiliation: Postdoc, Institut de Mathématiques de Bordeaux, France |
Mathematical Analysis of a Rigid Body in a Viscous Gas.
Fluid-structure interaction problems have been an important area of
research in recent years. Such systems occur, for instance, in
aerodynamics (flow around an aircraft), medicine (blood flow in vessels),
zoology (swimming of aquatic animals). The mathematical study of these
problems rises several challenges, the main one being due to the fact that
the domain filled by the fluid is one of the unknowns of the problem. In
this talk, we present some recent advances in the mathematical analysis of
some particulate flows. We show that a variety of such system admits a
global in time unique solution for small initial data in the $L^p$ - $L^q$
framework.
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26-04-2018 |
Debanjana Mitra |
Control of infinite dimensional linear systems
Speaker: Debanjana Mitra,
Last talk of this seminar series for this semester.
We discuss on feedback stabilizability of the infinite
dimensional system via the solution of Riccati equation. We touch upon
some interesting aspects of an optimal control problem. At the end, if
possible, we shall discuss on some interesting open problems in this
direction.
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24-04-2018 |
Mathematics Colloquium |
Branching Random Walks: Two Conjectures, Two Theorems and a Question
Branching random walk arises naturally in mathematical biology,
statistical physics and probability theory. Roughly speaking, it models a
system of growing particles or organisms that invades an environment in a
systematic fashion. Two famous statistical physicists (Eric Brunet and
Bernard Derrida) made conjectures about the long run configurations of
positions of particles in a branching random walk, and asked an open
question in their seminal work in 2011. Their question was answered
positively by Maillard (2013), and the conjectures were mathematically
proved recently by Madaule (2017) under certain conditions. In this talk,
we shall concentrate on the PhD thesis of Ayan Bhattacharya, who verified
Brunet-Derrida conjectures outside the Maillard-Madaule setup. If time
permits, some other recent related work will also be discussed.
This talk will be based on joint work with Ayan Bhattcharya and Rajat
Subhra Hazra. The papers are available in https://arxiv.org/abs/1411.5646
and https://arxiv.org/abs/1601.01656.
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23-04-2018 |
Prof. Kalyan B. Sinha, Jawharlal Nehru Centre for Advanced Scientific Research, Bangalore and IISc Bangalore |
Trace Formulas in Operator Theory
The celebrated Helton-Howe trace formula for hyponormal
operators is derived as a consequence of Krein's trace formula .
In many situation trace is a 'special' non-commutative integral of
'operator-functions ' and the said formula relates the non-commutative
integral with the 'volume Lebegue integral' ( in the usual
commutative sense ) .
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19-04-2018 |
Prof. Probal Chaudhuri, Theoretical Statistics and Mathematics Unit Indian Statistical Institute, Kolkata |
Deep Inside Data in Dimensions One, Two, Three, ... , Infinity
Prof. Chaudhuri has not given the abstract to keep the matter a
little mysterious!!
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19-04-2018 |
Debanjana Mitra |
Control of infinite dimensional linear systems
We continue the discussion of the asymptotic behavior of a C_0
semigroup. Then, the different notions of controllability of a linear
system in infinite dimension will be introduced in an abstract set up. For
example, we study the heat equation in details.
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17-04-2018 |
H. Ananthnarayan |
Initial ideals and applications
In the previous talk, we saw that given an ideal I in a
polynomial ring R, the monomials not in the initial ideal of I form a
basis of R/I. In this talk, we will see further examples of how to use the
initial ideal of I to get more information about I (or R/I).
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16-04-2018 |
Sudarshan Gurjar |
Holomorphic vector bundles on compact Riemann surfaces and its
other avatar, namely algebraic vector bundles on smooth, complex
projective curves has a long and rich history with important contributions
by the Indian Algebraic Geometry school. I will introduce this subject
with special focus on bundles which come from representations of the
fundamental group of the surface. Much of the talk will be accessible to
Ph.D students.
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09-04-2018 |
Asif Shaikh (R A Podar College of Commerce and Economics) |
Galois Coverings of Schreier Graphs
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