Speaker: Aniruddha Samanta
Title/Abstract: Attached
Date/time: Tuesday, February 1 2022, 3 pm - 4 pm
Google meet link: To join the video meeting, click this link:
https://meet.google.com/qty-joci-rdh
Otherwise, to join by phone, dial +1 929-251-5508 and enter this
PIN: 364 520 942#
Time:
11:30am
Description:
Speaker: Rakesh Jana: Indian Institute of Technology Guwahati
Title/Abstract: Attached
Date/time: Wednesday, February 2 2022, 11.30 am - 12.30 pm
Google meet link: To join the video meeting, click this link:
https://meet.google.com/qty-joci-rdh
Otherwise, to join by phone, dial +1 929-251-5508 and enter this
PIN: 364 520 942#
Time:
2:30pm - 3:30pm
Description:
Reading Seminar
Thursday, 3 February · 2:30 – 3:30 pm
Google Meet joining info
Video call link: https://meet.google.com/auv-mwkn-ixh
The first speaker is Sarjick Bakshi. He will give two/three talks on the
following topics.
Title: Modular representations of Algebraic groups,
Abstract:
We will discuss a few important and classical theorems in the
representation theory of reductive algebraic groups like the
Borel-Weil-Bott theorem, Kempf's vanishing theorem. The main reference
would be Jantzen's book ``Representation theory of Algebraic Groups'' and a
note by Andersen ``Modular representation of Algebraic groups and Relations
to Quantum groups''.
Speaker: Luc Hillairet (Institut Denis Poisson, University of Orleans,France)
Time: 3 February 2022, Thursday, 6 pm
Title: Variations on Concentration
Abstract: Studying the concentration of eigenfunctions of Schrodinger or
Laplace-type operators is a well known problem of semiclassical analysis.
Useful tools for the latter include semiclassical measures, WKB expansion.
After recalling some classical results of this theory we will focus on
less classical ones that are related to the study of analytic
eigenbranches or eigenvalue spacing problems. Based on joint work with C.
Judge and J. Marzuola.
Speaker: *Adam Van Tuyl, McMaster University, Canada*Date/Time: *4* February 2022*,
6:30pm IST/ 1:00pm GMT / 8:00am ET *(joining time 6:15pm IST)
Gmeet link: meet.google.com/vcc-aywh-xgx
Title: Toric ideals of graphs and some of their homological invariants
Abstract: The study of toric ideals of graphs lies in the intersection of
commutative algebra, algebraic geometry, and combinatorics. Formally, if $G
= (V,E)$ is a finite simple graph with edge set $E =\{e_1,\ldots,e_s\}$ and
vertex set $V = \{x_1,\ldots,x_n\},$ then the toric ideal of $G$ is the
kernel of the ring homomorphism $\varphi:k[e_1,\ldots,e_s] \rightarrow
k[x_1,\ldots,x_n]$ where $\varphi(e_i) = x_jx_k$ if the edge $e_i =
\{x_j,x_k\}$. Ideally, one would like to understand how the homological
invariants (e.g. graded Betti numbers) of $I_G$ are related to the graph
$G$. In this talk I will survey some results connected to this theme, with
an emphasis on the Castelnuovo-Mumford regularity of these ideals.
For more information and links to previous seminars, visit the website
of VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar
Time:
2:30pm - 3:30pm
Description:
Reading Seminar
Thursday, 10 February · 2:30 – 3:30 pm
Google Meet joining info
Video call link: https://meet.google.com/auv-mwkn-ixh
The speaker is Sarjick Bakshi. He will give the second talk on the
following topics.
Title: Modular representations of Algebraic groups,
Abstract:
We will discuss a few important and classical theorems in the
representation theory of reductive algebraic groups like the
Borel-Weil-Bott theorem, Kempf's vanishing theorem. The main reference
would be Jantzen's book ``Representation theory of Algebraic Groups'' and a
note by Andersen ``Modular representation of Algebraic groups and Relations
to Quantum groups''.
Time:
5:30pm
Description:
Speaker: Shunsuke Takagi, University of Tokyo, Japan.
Date/Time: 11 February 2022, 5:30pm IST/ 12:00pm GMT / 7:00am ET (joining
time 5:15pm IST).
Gmeet link: meet.google.com/ytj-rdzc-tay
Title: Kodaira vanishing for thickenings of globally $F$-regular varieties.
Abstract: Blickle-Bhatt-Lyubeznik-Singh-Zhang proved that if $X$ is a
projective variety over a field $k$ of characteristic zero with isolated
complete intersection singularities, then the Kodaira vanishing theorem
holds for all thickenings of $X$. What if $k$ is of positive
characteristic? Kodaira vanishing can fail in positive characteristic, but
it still holds for Frobenius split varieties. In this talk, I will discuss
Kodaira vanishing for thickenings of globally $F$-regular varieties, a
special class of Frobenius split varieties. This talk is based on joint
work with Kenta Sato.
For more information and links to previous seminars, visit the website of
VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar
Time:
2:30pm - 3:45pm
Description:
Reading Seminar
Thursday, 17 February · 2:30 – 3:45 pm
Google Meet joining info
Video call link: https://meet.google.com/auv-mwkn-ixh
The speaker is Sarjick Bakshi. He will give the 3rd talk on the
following topics.
Title: Modular representations of Algebraic groups,
Abstract:
We will discuss a few important and classical theorems in the
representation theory of reductive algebraic groups like the
Borel-Weil-Bott theorem, Kempf's vanishing theorem. The main reference
would be Jantzen's book ``Representation theory of Algebraic Groups'' and a
note by Andersen ``Modular representation of Algebraic groups and Relations
to Quantum groups''.
Speaker: Bruno Premoselli (Université Libre de Bruxelles, Belgium)
Time: February 17, Thursday, 4 pm (Indian Standard Time)
Title: A priori estimates for sign-changing solutions of critical elliptic
equations of Schrodinger-Yamabe type
Abstract: In this talk we consider sign-changing solutions of critical
Yamabe-Schrodinger type equations of second order. Unlike their positive
counterpart these solutions have no direct physical or geometrical
meaning, but have been shown to arise in geometrical contexts. They appear
for instance as extremals for higher eigenvalues minimisation problems in
a given conformal class. We describe in this talk the structure of
bubbling sign changing solutions for these equations and provide a
detailed asymptotic description, in strong spaces, of the blow-up. As a
consequence we prove some precompactness results for the set of
energy-bounded solutions of these equations. Some of these results have
been obtained in collaboration with J. Vétois (McGill University).
Google Meet joining info:
Video call link: https://meet.google.com/ptb-uyyu-zas
Or dial: (US) +1 484-841-8292 PIN: 147 605 745#
Time:
5:30pm
Description:
Speaker: Liran Shaul, Charles University, Prague.
Date/Time: 18 February 2022, 5:30pm IST/ 12:00pm GMT / 7:00am ET (joining
time 5:15pm IST).
Gmeet link: meet.google.com/osq-afmn-san
Title: Special classes of rings in derived commutative algebra.
Abstract: The classes of regular, Gorenstein and Cohen-Macaulay rings are
among the most important classes of rings in commutative algebra and
algebraic geometry. In this talk we recall the definitions and basic
properties of these classes, and then explain how to generalize each of
them to derived commutative algebra, in the context of commutative
differential graded algebras. We further explain how each of these
generalizations arise naturallyin various algebraic geometry contexts and
discuss some applications.
For more information and links to previous seminars, visit the website of
VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar
Time:
2:30pm - 3:45pm
Description:
Reading Seminar
Thursday, 24 February · 2:30 – 3:45 pm
Google Meet joining info
Video call link: https://meet.google.com/auv-mwkn-ixh
Website
The speaker is Sarjick Bakshi. He will give the 4th talk on the following topics.
Title: Modular representations of Algebraic groups,
Abstract:
We will discuss a few important and classical theorems in the representation theory of reductive algebraic groups like the Borel-Weil-Bott theorem, Kempf's vanishing theorem. The main reference would be Jantzen's book ``Representation theory of Algebraic Groups'' and a note by Andersen ``Modular representation of Algebraic groups and Relations to Quantum groups''.
Speaker: Pierre-Damien Thizy (Institut Camille Jordan, Université Claude
Bernard Lyon 1, France)
Time: February 24, Thursday, 5:30 pm
Title: Large blow-up sets for Q-curvature equations
Abstract: On a bounded domain of the Euclidean space $\mathbb{R}^{2m}$,
m>1, Adimurthi, Robert and Struwe pointed out that, even assuming a volume
bound $\int e^{2mu} dx\le C$, some blow-up solutions for prescribed
Q-curvature equations $(-\Delta)^m u= Q e^{2m u}$ without boundary
conditions may blow-up not only at points, but also on the zero set of
some nonpositive nontrivial polyharmonic function. This is in striking
contrast with the two dimensional case (m=1). During this talk, we will
discuss the construction of such solutions which involve (possible
generalizations of) the Walsh-Lebesgue theorem and some issues about
elliptic problems with measure data.
Google Meet joining info
Video call link: https://meet.google.com/efe-orej-zet
Or dial: (US) +1 651-560-3980 PIN: 954 349 109#
Time:
11:30am - 12:30pm
Description:
Speaker: Ankit Mishra, IIT Bombay
February 25 (Friday), 11:30-12:30.
Link : https://meet.google.com/jvr-izyy-ngd?authuser=0
Title : Hilbert series of CM local rings with
$e_2=e_1-e+1$ and MCM modules over hypersurface rings.
Time:
2:30pm - 3:30pm
Description:
Date: February 25 (Friday), 2.30 - 3.30 pm
Link: meet.google.com/pbb-odky-xvs
Title: Generalization of Serre Splitting to monoid algebras R[M]
Abstract: In the search for an answer to his conjecture, Serre gave a
splitting theorem which states that for a commutative noetherian ring R
and a projective R-module P of rank r, if r > dim(R), then P admits a
splitting with a free direct summand. This result, often aptly referred to
as Serre splitting theorem, shrinks the class of projective R-modules one
needs to study to projective R-modules of rank < dim(R) + 1. One may thus
ask if a similar splitting exists for projective R[M]-modules of rank >
dim(R), when M is a submonoid of Z^n.
This problem will be addressed in two parts. In the first part, when
rank(P) coincides with dim(R[M]), the said splitting will be demonstrated.
The second part will tackle the problem when rank(P) dips even further,
i.e., dim(R) < rank(P) < dim(R[M])-1. For n > 0, we define classes of
monoids M_n such that if M in M_n is seminormal and rank(P) > dim(R[M]) –
n, then P admits a splitting. As a consequence, it can be shown that for a
projective module P over Segre extensions S_mn over R, splitting is
possible when rank(P) > dim(S_mn)-[(m+n-1)/min(m,n)]. We will also discuss
the possibilities of splitting under monic inversion.
Time:
4:00pm - 5:00pm
Description:
February 25 (Friday), 4:00-5:00.
Link : https://meet.google.com/jvr-izyy-ngd?authuser=0
Title : Effects of perturbation on low energy Laplace eigenfunctions
Abstract : In this talk, we will discuss the effects of perturbation on
certain topological and geometrical properties of the nodal sets/vanishing
sets of Laplace eigenfunctions. Our discussion will be centred around a
well-known conjecture of Payne which states that: the zero set
corresponding to the second Laplace eigenfunction of any bounded planar
domain should intersect the boundary at exact two points. We will look
into certain stability properties of the nodal sets and obtain some
interesting results concerning the conjecture.
Time:
6:30pm
Description:
Speaker: K. Sather-Wagstaff, Clemson University, South Carolina.
Date/Time: 25 February 2022, 6:30pm IST/ 1:00pm GMT / 8:00am ET (joining
time 5:15pm IST).
Gmeet link: meet.google.com/rco-ewra-xmh
Title: Monomial Ideals Arising from Graph Domination Problems.
Abstract: Graph domination problems are ubiquitous in graph theory. In the
broadest terms, they ask how one can ‘observe’ an entire graph by
designating a certain list of vertices, following a proscribed list of
rules. An example of this is the vertex covering problem which happens to
describe the irredundant irreducible decomposition of the edge ideal of a
graph. In this talk, we will survey recent work with various collaborators
on other monomial ideal constructions that arise from other graph
domination problems, including one coming from electrical engineering.
For more information and links to previous seminars, visit the website of
VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar