Speaker: Dr. Mahendra Verma (Ben-Gurion University, Israel)
Time & Date: 12:00 noon, Monday, 05th February 2018
Venue: Ramanujan Hall
Title: Disjointness of models.
Abstract: attached
Time:
2:00pm
Location:
Ramanujan Hall, Department of Mathematics
Description:
CACAAG seminar
Date & Time : 5th February, 2pm
Venue : Ramanujan Hall
Speaker: Ashwin Deopurkar
Title: Riemann-Roch and Brill-Noether theory for tropical curves
Time:
4:00pm-5:00pm
Location:
Ramanujan Hall Department of Mathematics
Description:
Statistics seminar
Date & Time : 5th February, 4 p.m.-- 5 p.m.
Venue: Ramanujan Hall
Speaker: Monika Bhattacharjee, Post Doctoral Fellow
Information Institute, University of Florida, USA.
Title: Change point estimation in dynamic stochastic block model
Abstract: We shall consider a dynamic stochastic block model with single
change point. An easily implementable algorithm based on maximum
pseudo-likelihood method and spectral clustering will be proposed for
estimating the change point. We shall also estimate the edge-probability
matrices and community structures before and after the change point. The
convergence rate and asymptotic distribution for these estimators will be
discussed and compared with other existing works in the literature. This is
joint work with Moulinath Banerjee and George Michailidis.
Time:
11:45am-1:00pm
Location:
Room No. 215, Department of Mathematics
Description:
Commutative Algebra Seminar
Speaker: Rajiv Garg
Date & Time: 6th February, 11:45am-13:00pm
Venue: Room 215
Title: Boij-S\ddot{\text{o}}derberg Theory over Standard Graded Rings
Abstract: In 2009, Eisenbud and Schreyer prove that extremal rays of Betti
cone over
a polynomial ring are spanned by Betti diagrams of pure Cohen-Macaulay
S-modules,
where S={\sf k}[X_1,\dots, X_n]. In this talk, we discuss
Boij-S\ddot{\text{o}}derberg theory for standard
graded {\sf k}-algebras. We note the obstacles in using their techniques in
the general situation
and identify classes of rings where we can prove some of these results.
Time:
3:00pm
Description:
Speaker: Pranav Pandit
Date & Time: 6 February, 3pm
Venue: Room 215
Title: Categorical Kähler Geometry: from derived categories to dynamical
systems
Abstract:Mirror symmetry is a phenomenon predicted by string theory in
physics.
It allows one to translate questions in symplectic geometry to questions
in complex geometry, and vice versa. The homological mirror symmetry
program interprets mirror symmetry within the unifying categorical
framework of derived noncommutative geometry. After introducing these
ideas, I will describe an approach to a theory of Kähler metrics in
derived noncommutative geometry. We will see how this leads to (i) a
non-Archimedean categorical analogue of the Donaldson-Uhlenbeck-Yau
theorem, inspired by symplectic geometry, and (ii) the discovery of a
refinement of the Harder-Narasimhan filtration which controls the
asymptotic behavior of certain geometric flows. This talk is based on
joint work with Fabian Haiden, Ludmil Katzarkov, and Maxim Kontsevich.
Time:
4:15pm-5:00pm
Location:
Ramanujan Hall, Department of Mathematics
Description:
Mathematics Colloquium
Speaker: Prof. Michael J. Barany from
Dartmouth College
Date & Time: 7th February, 4-5pm
Venue: Ramanujan Hall
Title: A Synthesis and a Simplification: Difficulty and differentiation in
the intercontinental history of the theory of distributions.
Abstract: Between 1945 and 1960, French mathematician Laurent Schwartz’s
theory of distributions became one of the first of a new kind of
mathematical theory: one shared and studied almost from the start across
multiple continents. Today, distributions have mostly settled into a
comfortable niche in the basic graduate (or in some cases advanced
undergraduate) mathematics curriculum, as a theory many researchers use
routinely as a basic tool while many others safely ignore it. But in those
early years the theory’s leading expositors came to many different answers
about how difficult the theory was, who should study it, and what that
meant for the theory’s place in modern mathematics. My talk will explain
the early history of Schwartz’s theory with special attention to the
question of how difficult the theory was understood to be in different
contexts across five continents. The fact that there were so many different
answers to the question of distributions’ difficulty, I argue, can explain
how the theory was able to spread so far and so quickly. This, in turn,
calls attention to the changing nature of mathematical theories themselves
in the mid-twentieth century.
Time:
4:00pm
Description:
Speaker: Dr. Nishant Chandgotia, Tel Aviv university
Date & Time - 8-2-18, Thursday, 4 PM
Title: Universal models in ergodic theory
Abstract: In 1970, Krieger proved that any free ergodic probability
preserving invertible transformation of finite entropy can be modelled by
A^Z, the set of unconstrained bi-infinite sequences in some finite alphabet
A. This result has seen many generalisations for more constrained systems
and for actions of other groups. Along with Tom Meyerovitch, we prove that
under certain general mixing conditions $Z^d$-topological dynamical systems
can model all free ergodic probability preserving Z^d actions of lower
entropy. In particular, we show that these mixing conditions are satisfied
by proper colourings of the Z^d lattice (colourings of the Z^d lattice
where adjacent colours are distinct) and the domino tilings of Z^2 lattice,
thus answering a question by Şahin and Robinson. The talk will begin with
an introduction to the terms mentioned in the abstract and should be
accessible to a general audience.