BEGIN:VCALENDAR
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PRODID:researchseminars.org
CALSCALE:GREGORIAN
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BEGIN:VEVENT
SUMMARY:Nikolay Grantcharov (University of Chicago)
DTSTART:20201202T163000Z
DTEND:20201202T174500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/1
DESCRIPTION:Title: Finite-dimensional representation theory of the queer Lie
superalgebra q(n)\nby Nikolay Grantcharov (University of Chicago) as
part of STARS: Superalgebra Theory and Representations Seminar\n\n\nAbstra
ct\nWe will first describe some classical theory of the queer Lie superalg
ebras q(n)\, such as Clifford modules\, (generic) character formula for th
e irreducible representations\, and classification of the blocks of finite
-dimensional representations. Then we will focus our attention to q(3) and
provide an explicit description of the Ext-quivers of the blocks. A proof
of a ``virtual'' BGG reciprocity for q(n)\, which then gives the radical
filtrations of indecomposable projective objects for q(3)\, will be provid
ed.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Coulembier (University of Sydney)
DTSTART:20201216T080000Z
DTEND:20201216T091500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/3
DESCRIPTION:Title: A semisimple extension of the Takiff superalgebra\nby
Kevin Coulembier (University of Sydney) as part of STARS: Superalgebra Th
eory and Representations Seminar\n\n\nAbstract\nIn this talk\, I will give
an overview of the (finite dimensional) representation theory of a partic
ular semisimple Lie superalgebra. In particular\, I will explain characte
r formulas\, extension groups\, block decompositions\, invariant theory an
d Koszulity.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thorsten Heidersdorf (Bonn University)
DTSTART:20201209T163000Z
DTEND:20201209T174500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/4
DESCRIPTION:Title: Indecomposable summands in tensor products\nby Thorst
en Heidersdorf (Bonn University) as part of STARS: Superalgebra Theory and
Representations Seminar\n\n\nAbstract\nI will report on some progress to
understand indecomposable summands in tensor products of irreducible repre
sentations of $\\mathfrak{gl}(m|n)$. I will focus on the $\\mathfrak{gl}(m
|2)$-case ($m \\geq 2$) which exhibits many features of the general case.
The crucial tool is the Duflo-Serganova functor and some of its variants.\
n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Sherman (Ben Gurion University)
DTSTART:20201223T163000Z
DTEND:20201223T174500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/5
DESCRIPTION:Title: Around the classification of semisimple algebraic supergr
oups\nby Alex Sherman (Ben Gurion University) as part of STARS: Supera
lgebra Theory and Representations Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Krishanu Roy (Bar Ilan University)
DTSTART:20201230T163000Z
DTEND:20201230T174500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/6
DESCRIPTION:Title: Pi-systems and closed systems in symmetrizable Kac-Moody
algebras\nby Krishanu Roy (Bar Ilan University) as part of STARS: Supe
ralgebra Theory and Representations Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shifra Reif (Bar-Ilan University)
DTSTART:20210106T233000Z
DTEND:20210107T003000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/7
DESCRIPTION:Title: Grothendieck rings for queer Lie superalgebras\nby Sh
ifra Reif (Bar-Ilan University) as part of STARS: Superalgebra Theory and
Representations Seminar\n\n\nAbstract\nThe Grothendieck ring of the catego
ry of finite dimensional representations over a simple Lie algebra can be
described via the character map\, as a ring of functions invariant under t
he action of the Weyl group. This result was generalized to basic Lie supe
ralgebras by A. N. Sergeev and A. P. Veselov with additional invariance co
nditions.\n\nIn this talk we will discuss the ring of characters for queer
Lie superalgebras. In particular\, for the queer Lie supergroup $Q(n)$\,
we show that the ring is isomorphic to the ring of symmetric Laurent polyn
omials in $x_1\,...\,x_n$ such that the evaluation $x_1=-x_2=t$ is indepen
dent of $t$. We shall discuss the representation theoretical meaning of th
is evaluation.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Volodymyr Mazorchuk (Uppsala University)
DTSTART:20210127T163000Z
DTEND:20210127T174500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/8
DESCRIPTION:Title: Bigrassmannian permutations and Verma modules\nby Vol
odymyr Mazorchuk (Uppsala University) as part of STARS: Superalgebra Theor
y and Representations Seminar\n\n\nAbstract\nIn this talk I will describe
how bigrassmannian\npermutations control the socle of the cokernel of\nemb
eddings of Verma modules for sl_n. An applciation of\nthis is a descriptio
n of the socle of the cokernel of\nhomomorphisms between Verma modules for
the periplective Lie\nsuperalgebra. This is based on two joint works:\non
e with Hankyung Ko and Rafael Mrden and another one with\nChih-Whi Chen.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Sherman (Ben Gurion University)
DTSTART:20210310T171500Z
DTEND:20210310T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/9
DESCRIPTION:Title: The full ghost centre and a projectivity polynomial\n
by Alex Sherman (Ben Gurion University) as part of STARS: Superalgebra The
ory and Representations Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jae-Hoon Kwon (Seoul National University)
DTSTART:20210317T080000Z
DTEND:20210317T091500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/10
DESCRIPTION:Title: A combinatorial character formula for the periplectic Li
e superalgebra.\nby Jae-Hoon Kwon (Seoul National University) as part
of STARS: Superalgebra Theory and Representations Seminar\n\n\nAbstract\nI
n this talk\, we introduce a combinatorial formula for a finite-dimensiona
l irreducible representation of the periplectic Lie superalgebra.\nThe irr
educible character is given by a cancellation-free alternating sum over th
e characters of thick or thin Kac modules\, where the highest weights for
the Kac modules appearing here are characterized in terms of a ribbon titl
ing. The formula is obtained by using the result on the decomposition mult
iplicity of a simple module in Kac modules due to Balagovic et al. This is
joint work with B.-H. Hwang (arXiv:2101.05642).\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jon Kujawa (University of Oklahoma)
DTSTART:20210407T161500Z
DTEND:20210407T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/11
DESCRIPTION:Title: Support varieties and complexity for Lie superalgebras\nby Jon Kujawa (University of Oklahoma) as part of STARS: Superalgebra
Theory and Representations Seminar\n\n\nAbstract\nSupport varieties have l
ong history in modular representation theory and are known to capture impo
rtant information. A relevant example is the fact their dimension equals
the rate of growth of a module's minimal projective resolution (aka the mo
dule's complexity). Motivated by these successes\, Boe\, Kujawa\, and Nak
ano introduced support varieties to the study of complex representations o
f Lie superalgebras. They are known to contain valuable information but a
re still mysterious in a number of respects -- including their relationshi
p to complexity. In this talk we will explain explicit computations of bo
th support varieties and complexity for Lie superalgebras which we think a
re illuminating.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chih-Whi Chen (Academia Sinica)
DTSTART:20210421T120000Z
DTEND:20210421T131500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/12
DESCRIPTION:Title: Simple supermodules for classical Lie superalgebras\
nby Chih-Whi Chen (Academia Sinica) as part of STARS: Superalgebra Theory
and Representations Seminar\n\n\nAbstract\nThe problem of classification o
f all simple modules for a given Lie algebra is rather difficult. Some kin
d of solution exists only for the Lie algebra $\\mathfrak{sl}(2)$ due to B
lock's classification theorem. \n\n A finite-dimensional Lie superalgebra
$\\mathfrak{g}=\\mathfrak{g}_{\\bar 0}\\oplus\\mathfrak{g}_{\\bar 1}$ is c
alled quasireductive if $\\mathfrak{g}_{\\bar 0}$ is a reductive Lie algeb
ra and $\\mathfrak {g}_{\\bar 1}$ is a completely reducible $\\mathfrak {g
}_{\\bar 0}$-module. In this talk\, we will mainly focus on simple superm
odules for quasireductive type-I Lie superalgebras. We explain the conne
ction between simple supermodules over $\\mathfrak g$ and simple modules o
ver the underlying Lie algebra $\\mathfrak g_{\\overline 0}$. As an applic
ation\, we classify simple Whittaker supermodules for the type-I Lie super
algebras $\\mathfrak{gl}(m|n)$\, $\\mathfrak{osp}(2|2n)$ and $\\mathfrak{p
e}(n)$. \n\n\nThis talk is based on the joint work with Kevin Coulembier
and Volodymyr Mazorchuk.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nick Davidson (Reed College)
DTSTART:20210512T161500Z
DTEND:20210512T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/13
DESCRIPTION:Title: Type P Webs and Howe Duality\nby Nick Davidson (Reed
College) as part of STARS: Superalgebra Theory and Representations Semina
r\n\n\nAbstract\nWebs are combinatorially defined diagrams which encode ho
momorphisms between tensor products of certain representations of Lie (sup
er)algebras. I will describe some recent work which defines webs associat
ed to the type P Lie superalgebra\, and then gives a generators-and-relati
ons presentation for the type P enveloping algebra. Using these construct
ions\, we deduce an analog of Howe duality in the type P setting.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hadi Salmasian (University of Ottawa)
DTSTART:20210602T163000Z
DTEND:20210602T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/14
DESCRIPTION:Title: Eigenvalues of Capelli operators for superspherical harm
onics\, Deligne's category Rep(O_t)\, and the Dougall-Ramanujan identity\nby Hadi Salmasian (University of Ottawa) as part of STARS: Superalgebr
a Theory and Representations Seminar\n\n\nAbstract\nGiven a module $V$ of
a Lie (super)algebra $g$ such that $S(V)$ is completely reducible and mult
iplicity-free\, one can define a distinguished basis of "Capelli operators
" for the algebra of $g$-invariant differential operators on $V$. The "Cap
elli Eigenvalue Problem" (CEP) is the problem of computing the eigenvalues
of this basis. For reductive Lie algebras\, the CEP was first studied by
Kostant and Sahi\, and then in Sahi's work it culminated in the theory of
interpolation Jack polynomials. More recently\, Sahi\, Serganova\, and S.
solved the analogous CEP for basic Lie superalgebras.\n\nIn this talk\, we
will choose $V$ to be an orthosymplectic superspace and $g:=gosp(V)$ to b
e the Lie superalgebra of similitudes of $V$. Then it is known that in gen
eral $S(V)$ is neither completely reducible\, nor multiplicity-free. Never
theless\, we show that it is still possible to define a Capelli basis\, an
d then we compute two formulas for their eigenvalues. Along the way\, the
Dougall-Ramanujan hypergeometric identity and Deligne's category $Rep(O_t)
$ appear as pleasant surprises. This talk is based on a joint work with Si
ddhartha Sahi and Vera Serganova.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ian Musson (Wisconsin University)
DTSTART:20210630T130000Z
DTEND:20210630T141500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/15
DESCRIPTION:Title: Explicit expressions for Shapovalov elements in Type A\nby Ian Musson (Wisconsin University) as part of STARS: Superalgebra Th
eory and Representations Seminar\n\n\nAbstract\nhttps://drive.google.com/f
ile/d/1GrhkZp3qM2jhbJRNcQn5mVejR_Hqgw-B/view?usp=sharing\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shun-Jen Cheng (Academia Sinica)
DTSTART:20210707T070000Z
DTEND:20210707T083000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/16
DESCRIPTION:Title: Representation theory of a semisimple extension of the T
akiff superalgebra\nby Shun-Jen Cheng (Academia Sinica) as part of STA
RS: Superalgebra Theory and Representations Seminar\n\n\nAbstract\nIn this
talk we shall discuss the representation theory of a semisimple extension
of a Takiff superalgebra. We determine the blocks in both the finite-dime
nsional and BGG module categories and also classify the Borel subalgebras.
We also give a description of all extension groups between two finite-dim
ensional simple objects. This is a joint work with Kevin Coulembier.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Graham Hawkes (Ben-Gurion University)
DTSTART:20210721T080000Z
DTEND:20210721T090000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/17
DESCRIPTION:Title: Schubert Polynomials of Type B\nby Graham Hawkes (Be
n-Gurion University) as part of STARS: Superalgebra Theory and Representat
ions Seminar\n\nLecture held in Also LIVE at Weizmann Institute\, Room 1.\
n\nAbstract\nWhen Kirillov and Fomin began searching for what might be the
natural hyperoctohedral version of the type A Schubert polynomials\, the
y set out a series of properties that they believed these poynomials ought
to have. These consist in (1) satisfying the recurrence relations with d
ivided difference operators\, (2) having nonnegative coeffiecients\, and (
3) producing the type C Stanley symmetric function as a certain limit. \n\
nWhile satisfying most of these properties in addition to others\, the pol
ynomials defined\, unfortunatley\, do not satisfy the divided difference r
elation for the special generator of the hyperoctahedral group. Moreover\
, while type A Schubert polynomials can in fact be easily constructed via
succesively applying divided difference to a special starting monomial (na
mely\, $x_1^0x_2^1\\cdots x_n^{n-1}$) this is not true of their type B can
didate (in fact this follows from the statement above).\n\nWe introduce a
different candidate for the octahedral Schubert polynomial\, constructing
it directly from the monomial $x_1^1x_2^3\\cdots x_n^{2n-1}$ via divided
difference operators. By construction the result satisfies propery (1) ab
ove. Conjecturely it also satisfies (2) and (3) and we have verified thes
e conjectures up to $n=4$. \n\nIn this talk we review the results for the
type A case and show what roadblocks appear if one tries to adapt the proo
fs in the type A case to the type B case. We also mention some partial re
sults we believe may be useful in eventually proving the conjecture.\n\nTh
is is a a special talk in algebraic combinatorics. We will do our best to
show this talk via ZOOM\, at the usual address:\n\nhttps://us02web.zoom.u
s/j/88189258443?pwd=S3JLcElXTUpadktqZ0VLWHNmVXdiQT09\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shrawan Kumar (UNC)
DTSTART:20211110T171500Z
DTEND:20211110T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/18
DESCRIPTION:Title: ROOT COMPONENTS FOR TENSOR PRODUCT OF AFFINE KAC-MOODY L
IE ALGEBRA MODULES\nby Shrawan Kumar (UNC) as part of STARS: Superalge
bra Theory and Representations Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gus Lehrer (University of Sydney)
DTSTART:20211124T080000Z
DTEND:20211124T091500Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/19
DESCRIPTION:Title: Invariant theory for the orthosymplectic super group.\nby Gus Lehrer (University of Sydney) as part of STARS: Superalgebra The
ory and Representations Seminar\n\n\nAbstract\nWe show how invariants of t
he orthosymplectic super group may be converted into invariants of super $
GL_n$\, using algebraic geometric arguments. By this means\, we obtain pre
cise versions of the first and second fundamental theorems of invariant th
eory for these groups\, despite the absence of semisimplicity.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alistair Savage (University of Ottawa)
DTSTART:20211208T171500Z
DTEND:20211208T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/20
DESCRIPTION:Title: Affine oriented Frobenius Brauer categories\nby Alis
tair Savage (University of Ottawa) as part of STARS: Superalgebra Theory a
nd Representations Seminar\n\n\nAbstract\nTo any Frobenius superalgebra $A
$ we associate an oriented Frobenius Brauer category and an affine oriente
d Frobenius Brauer category. We define natural actions of these categorie
s on categories of supermodules for general linear Lie superalgebras $\\ma
thfrak{gl}_{m|n}(A)$ with entries in $A$. These actions generalize those
on module categories for general linear Lie superalgebras and queer Lie su
peralgebras\, which correspond to the cases where $A$ is the ground field
and the two-dimensional Clifford superalgebra\, respectively.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexandra Utiralova (MIT)
DTSTART:20220112T171500Z
DTEND:20220112T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/21
DESCRIPTION:Title: Harish-Chandra bimodules in complex rank\nby Alexand
ra Utiralova (MIT) as part of STARS: Superalgebra Theory and Representatio
ns Seminar\n\n\nAbstract\nDeligne tensor categories are defined as an inte
rpolation of the categories of representations of groups GL_n\, O_n\, Sp_{
2n} or S_n to the complex values of the parameter n. One can extend many c
lassical representation-theoretic notions and constructions to this contex
t. These complex rank analogs of classical objects provide insights into t
heir stable behavior patterns as n goes to infinity.\nI will talk about so
me of my results on Harish-Chandra bimodules in Deligne categories. It is
known that in the classical case simple Harish-Chandra bimodules admit a c
lassification in terms of W-orbits of certain pairs of weights. However\,
the notion of weight is not well-defined in the setting of Deligne categor
ies. I will explain how in complex rank the above-mentioned classification
translates to a condition on the corresponding (left and right) central c
haracters.\nAnother interesting phenomenon arising in complex rank is that
there are two ways to define Harish-Chandra bimodules. That is\, one can
either require that the center acts locally finitely on a bimodule M or th
at M has a finite K-type. The two conditions are known to be equivalent fo
r a semi-simple Lie algebra in the classical setting\, however\, in Delign
e categories that is no longer the case. I will talk about a way to constr
uct examples of Harish-Chandra bimodules of finite K-type using the ultrap
roduct realization of Deligne categories.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Volodymyr Mazorchuk (Uppsala University)
DTSTART:20220119T171500Z
DTEND:20220119T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/22
DESCRIPTION:Title: Category O is Auslander regular\nby Volodymyr Mazorc
huk (Uppsala University) as part of STARS: Superalgebra Theory and Represe
ntations Seminar\n\n\nAbstract\nIn this talk I will prove that category O
and its several generalizations are Auslander regular\, which is a conditi
on\ndefined in terms of homological dimensions of structural modules.\n\nT
his is a joint work with Hankyung Ko and Rafael Mrden (answering a questio
n by Rene Marczinzik).\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivan Penkov (Jacobs University)
DTSTART:20220202T171500Z
DTEND:20220202T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/23
DESCRIPTION:Title: Some results and open problems on representations of cla
ssical Lie (super)algebras at infinity\nby Ivan Penkov (Jacobs Univers
ity) as part of STARS: Superalgebra Theory and Representations Seminar\n\n
\nAbstract\nI will describe known results and open problems concerning var
ious representation categories of classical Lie (super)algebras\nat infini
ty\, and will pose the problem of classifying primitive ideals of certain
enveloping (super)algebras\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrew Snowden (University of Michigan)
DTSTART:20220302T171500Z
DTEND:20220302T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/24
DESCRIPTION:Title: Cohomology of flag supermanifolds and resolutions of det
erminantal ideals\nby Andrew Snowden (University of Michigan) as part
of STARS: Superalgebra Theory and Representations Seminar\n\n\nAbstract\nI
will explain joint work with Steven Sam in which we completely compute th
e coherent cohomology of super Grassmannians\, and some other flag superva
rieties. Our main observation is that these groups are\nclosely related to
the free resolutions of (certain generalizations of) determinantal ideals
.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Sherman (Ben Gurion University)
DTSTART:20211020T161500Z
DTEND:20211020T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/25
DESCRIPTION:Title: Minicourse on Duflo-Serganova functors (part 1)\nby
Alex Sherman (Ben Gurion University) as part of STARS: Superalgebra Theory
and Representations Seminar\n\n\nAbstract\nAbout the course:\nGiven an od
d element x in a Lie superalgebra g satisfying [x\, x] = 0\, we have that
x^2 = 0 in the\nuniversal enveloping algebra of g\, and so for every g-mod
ule M\, we can define the cohomology\nDS_x (M) := Ker (x) / Im(x).\nIn fac
t\, DS(M) is a module for the Lie superalgebra\ng_x := DS_x (g) = Ker ad(x
) / Im ad(x)\,\nwhich is a Lie superalgebra of smaller rank than g. \nFor
example\, if g = gl(m|n) and x is a root vector\, then g_x = gl(m − 1|n
− 1). \nDuflo and Serganova defined the functor DS_x from the category o
f g-modules to the category of g_x-modules which is now called the Duflo
–Serganova functor. This minicourse will give an overview of the theory
of Duflo–Serganova functors and the recent advances in their study.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Sherman and Crystal Hoyt (Ben Gurion University and Bar Ilan
University)
DTSTART:20211027T161500Z
DTEND:20211027T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/26
DESCRIPTION:Title: Minicourse on Duflo-Serganova functors (part 2)\nby
Alex Sherman and Crystal Hoyt (Ben Gurion University and Bar Ilan Universi
ty) as part of STARS: Superalgebra Theory and Representations Seminar\n\n\
nAbstract\nAbout the course:\nGiven an odd element x in a Lie superalgebra
g satisfying [x\, x] = 0\, we have that x^2 = 0 in the\nuniversal envelop
ing algebra of g\, and so for every g-module M\, we can define the cohomol
ogy\nDS_x (M) := Ker (x) / Im(x).\nIn fact\, DS(M) is a module for the Lie
superalgebra\ng_x := DS_x (g) = Ker ad(x) / Im ad(x)\,\nwhich is a Lie su
peralgebra of smaller rank than g. \nFor example\, if g = gl(m|n) and x is
a root vector\, then g_x = gl(m − 1|n − 1). \nDuflo and Serganova def
ined the functor DS_x from the category of g-modules to the category of g_
x-modules which is now called the Duflo–Serganova functor. This minicour
se will give an overview of the theory of Duflo–Serganova functors and t
he recent advances in their study.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alex Sherman and Crystal Hoyt (Ben Gurion University and Bar Ilan
University)
DTSTART:20211103T171500Z
DTEND:20211103T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/27
DESCRIPTION:Title: Minicourse on Duflo-Serganova functors (part 3)\nby
Alex Sherman and Crystal Hoyt (Ben Gurion University and Bar Ilan Universi
ty) as part of STARS: Superalgebra Theory and Representations Seminar\n\n\
nAbstract\nAbout the course:\nGiven an odd element x in a Lie superalgebra
g satisfying [x\, x] = 0\, we have that x^2 = 0 in the\nuniversal envelop
ing algebra of g\, and so for every g-module M\, we can define the cohomol
ogy\nDS_x (M) := Ker (x) / Im(x).\nIn fact\, DS(M) is a module for the Lie
superalgebra\ng_x := DS_x (g) = Ker ad(x) / Im ad(x)\,\nwhich is a Lie su
peralgebra of smaller rank than g. \nFor example\, if g = gl(m|n) and x is
a root vector\, then g_x = gl(m − 1|n − 1). \nDuflo and Serganova def
ined the functor DS_x from the category of g-modules to the category of g_
x-modules which is now called the Duflo–Serganova functor. This minicour
se will give an overview of the theory of Duflo–Serganova functors and t
he recent advances in their study.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elena Poletaeva (UT Rio Grande Valley)
DTSTART:20220309T171500Z
DTEND:20220309T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/28
DESCRIPTION:Title: On representations of finite $W$-algebras and super Yang
ians\nby Elena Poletaeva (UT Rio Grande Valley) as part of STARS: Supe
ralgebra Theory and Representations Seminar\n\n\nAbstract\nA finite $W$-al
gebra is certain associative algebra attached to a pair $(\\mathfrak{g}\,
e)$\, where\n$\\mathfrak{g}$ is a complex semisimple Lie algebra and $e\\
in \\mathfrak{g}$ is a nilpotent element.\nIt is a generalization of the u
niversal enveloping algebra $U(\\mathfrak{g})$.\nWe classify irreducible r
epresentations of finite $W$-algebra for the queer Lie superalgebra $Q(n)$
associated with the regular even nilpotent coadjoint orbits.\nWe use this
result to obtain a classification of irreducible finite-dimensional repre
sentations of the super Yangian $YQ(1)$.\n\n\nIt is a joint work with V. S
erganova.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:L. Andrew Jenkins (University of Georgia)
DTSTART:20211117T171500Z
DTEND:20211117T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/29
DESCRIPTION:Title: The nilpotent cone for classical simple Lie superalgebra
s\nby L. Andrew Jenkins (University of Georgia) as part of STARS: Supe
ralgebra Theory and Representations Seminar\n\n\nAbstract\nMany aspects of
the representation theory of a Lie algebra and its associated algebraic g
roup are governed by the geometry of their nilpotent cone. In this talk\,
we will introduce an analogue of the nilpotent cone $\\mathcal{N}$ for Lie
superalgebras and show that for a simple classical Lie superalgebra the n
umber of nilpotent orbits is finite. We will also show that the commuting
variety $\\mathcal{X}$ described by Duflo and Serganova\, which has applic
ations in the study of the finite dimensional representation theory of Lie
superalgebras\, is contained in $\\mathcal{N}$. Consequently\, the finite
ness result on $\\mathcal{N}$ generalizes and extends the work on the comm
uting variety. For the general linear Lie superalgebra $\\mathfrak{gl}(m|n
)$\, we will also discuss more detailed geometric results of $\\mathcal{N}
$. In particular\, we compute the dimensions of $\\mathcal{N}$ and the cen
tralizer of a nilpotent orbit\, describe the irreducible components of $\\
mathcal{N}$\, and show that $\\mathcal{N}$ is a complete intersection. Thi
s is joint work with Daniel Nakano from the University of Georgia.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Crystal Hoyt (Bar Ilan University)
DTSTART:20211229T123000Z
DTEND:20211229T133000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/30
DESCRIPTION:Title: Representations of the Cartan Type Lie superalgebra W(in
fty)\nby Crystal Hoyt (Bar Ilan University) as part of STARS: Superalg
ebra Theory and Representations Seminar\n\n\nAbstract\nThe Lie superalgebr
a W(infty) is the direct limit of finite-dimensional Cartan type Lie supe
ralgebras W(n) as n goes to infinity. In this talk\, we will discuss Z-gra
ded modules over W(infty). We introduce a category T_W of W(infty)-modules
which is closely related to the category T_gl of tensor sl(infty)-modules
introduced and studied by Dan-Cohen\, Serganova and Penkov. We show that
each simple module in T_W is isomorphic to the unique simple quotient of a
module induced from a simple module in T_gl\, and vice versa. This is joi
nt work with Lucas Calixto.\n\nThis talk is part of the Winter STARS works
hop. The webpage of the workshop can be found here:\nhttps://innaentova.wi
xsite.com/winterstars2021/\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thorsten Heidersdorf (Bonn University)
DTSTART:20211229T152000Z
DTEND:20211229T162000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/31
DESCRIPTION:Title: Indecomposable summands in tensor products\nby Thors
ten Heidersdorf (Bonn University) as part of STARS: Superalgebra Theory an
d Representations Seminar\n\n\nAbstract\nI will give an explicit descripti
on of the indecomposable summands in a tensor power\n\nV^{\\otimes r} wher
e V denotes the standard representation of the orthosymplectic supergroup
OSp(m|2n).\nAt the end I will ask what we know in general about the struct
ure of the indecomposable summands in a tensor product decomposition L(\\l
ambda) \\otimes L(\\mu) for irreducible representations of a supergroup su
ch as GL(m|n).\n\nThis talk is part of the Winter STARS workshop. The webp
age of the workshop can be found here:\nhttps://innaentova.wixsite.com/win
terstars2021/\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vadim Schechtman (Institut de Mathématiques de Toulouse)
DTSTART:20211229T140000Z
DTEND:20211229T150000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/32
DESCRIPTION:Title: PROBs and sheaves\nby Vadim Schechtman (Institut de
Mathématiques de Toulouse) as part of STARS: Superalgebra Theory and Repr
esentations Seminar\n\n\nAbstract\nI propose to explain how certain univer
sal bialgebra allows us to give a linear algebra description of categories
of perverse sheaves over all symmetric powers of the complex plane\, smoo
th along the diagonal stratification. This bialgebra is closely related to
"contingency tables" introduced by Karl Pearson more than one hundred year
s ago.\n\nThis is a joint work with Mikhail Kapranov.\n\nThis talk is part
of the Winter STARS workshop. The webpage of the workshop can be found he
re:\nhttps://innaentova.wixsite.com/winterstars2021/\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aleksandr Sergeev (Saratov State University)
DTSTART:20220323T161500Z
DTEND:20220323T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/33
DESCRIPTION:Title: Canonical bilinear form and Euler characters\nby Ale
ksandr Sergeev (Saratov State University) as part of STARS: Superalgebra T
heory and Representations Seminar\n\n\nAbstract\nAn explicit formula for t
he canonical bilinear form on the Grothendieck ring of the Lie supergroup
GL(n\, m) is given. As an application we get an algorithm for the decompos
ition Euler characters in terms of charactrers of irreducible modules in t
he category of partially polynomial modules.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Vladimir Stukopin (Moscow Institute of Physics and Technology)
DTSTART:20220330T161500Z
DTEND:20220330T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/34
DESCRIPTION:Title: Hopf superalgebra structures on quantum superalgebras\,
super Yangians and quantum loop superalgebras\nby Vladimir Stukopin (M
oscow Institute of Physics and Technology) as part of STARS: Superalgebra
Theory and Representations Seminar\n\n\nAbstract\nI am going to tell about
description and classification of Hopf superalgebras structures and quisi
triangular structures on quantum superalgebras\, super Yangians and quantu
m loop superalgebras. It will be consider relation between Hopf superalgeb
ra structures and construction of Weyl groupoid in detail in the case of q
uantum superalgebra $U_q(sl(m\,n))$. I will also tell about generalization
of this construction on the case infinite dimensional quantum superalgebr
as such that super Yangians and quantum loop superalgebras. I also descri
be the structures of tensor categories on Yangian and quantum loop superal
gebra categories of representations\, which are analogues of the category
$\\mathfrak{O}$ and investigate the relation between them. It will be con
struct an isomorphism in the category of Hopf superalgebras between the co
mpletion of the super Yangian and of the completion quantum loop superalge
bra. A theorem on the equivalence of tensor categories of modules over the
super Yangian and the quantum loop superalgebra is formulated also. It wi
ll be also described relation between different quasitriangular structures
(universal R-matrices) on the super Yangians and quantum loop superalgebr
as\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Weiqiang Wang (University of Virginia)
DTSTART:20220727T161500Z
DTEND:20220727T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/35
DESCRIPTION:Title: Kazhdan-Lusztig bases and quantum Schur dualities ABC\nby Weiqiang Wang (University of Virginia) as part of STARS: Superalgebr
a Theory and Representations Seminar\n\n\nAbstract\nThe type A quantum Sch
ur duality (due to Jimbo) concerns about commuting actions on a tensor spa
ce of a quantum group and a Hecke algebra of type A. Several years ago\, a
duality between a Hecke algebra of type B and an i-quantum group arising
from quantum symmetric pairs was obtained by Bao and myself (and Watanabe
in unequal parameters). Both dualities are intimately related to canonical
bases and (super) Kazhdan-Lusztig theory of type ABC(D). In this talk\, I
will explain a unification of both dualities involving i-quantum groups\,
which leads to a generalization of Kazhdan-Lusztig bases of type B. This
is joint work with Yaolong Shen (Virginia).\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Nakano (University of Georgia)
DTSTART:20220427T161500Z
DTEND:20220427T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/36
DESCRIPTION:Title: Sheaf cohomology via detecting subalgebras and BBW parab
olic subalgebras\nby Daniel Nakano (University of Georgia) as part of
STARS: Superalgebra Theory and Representations Seminar\n\n\nAbstract\nFift
een years ago\, Boe\, Kujawa and the speaker introduced the concept of det
ecting subalgebras for classical simple Lie superalgebras. These algebras
were constructed by using ideas from geometric invariant theory. More rece
ntly\, D. Grantcharov\, N. Grantcharov\, Wu and the speaker introduced the
concept of a BBW parabolic subalgebra. Given a ${\\mathfrak g}$\, one has
a triangular decomposition ${\\mathfrak g}={\\mathfrak n}^{-}\\oplus {\\m
athfrak f} \\oplus {\\mathfrak n}^{+}$ with ${\\mathfrak b}={\\mathfrak f}
\\oplus {\\mathfrak n}^{-}$ where ${\\mathfrak f}$ is a detecting subalgeb
ra and ${\\mathfrak b}$ is a BBW parabolic subalgebra. This holds for all
classical ``simple’’ Lie superalgebras\, and one can view ${\\mathfrak
f}$ as an analog of the maximal torus\, and ${\\mathfrak b}$ like a Borel
subalgebra. This setting also provide a useful method to define semisimpl
e elements and nilpotent elements\, and to compute various sheaf cohomolog
y groups $R^{\\bullet}\\text{ind}_{B}^{G} (-)$. \n\n \n\nIn this talk\, I
will provide a systematic treatment that allows us to study the behavior o
f these cohomology groups $H^{\\bullet}(\\lambda)=R^{\\bullet}\\text{ind}_
{B}^{G} L_{\\mathfrak f}(\\lambda)$ where $L_{\\mathfrak f}(\\lambda)$ is
an irreducible representation for the detecting subalgebra ${\\mathfrak f}
$. In particular\, we prove an analog of \n\nKempf's vanishing theorem and
the Bott-Borel-Weil theorem for large weights\, and investigate the struc
ture of $H^{1}(\\lambda)$. \n\n \n\nThis talk represents joint work with
David Galban.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christopher Drupieski (DePaul University)
DTSTART:20220511T161500Z
DTEND:20220511T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/37
DESCRIPTION:Title: Support varieties for Lie superalgebras and finite super
group schemes\nby Christopher Drupieski (DePaul University) as part of
STARS: Superalgebra Theory and Representations Seminar\n\n\nAbstract\nSup
port varieties are tools that assign to each representation of a group G (
or more generally\, a Hopf algebra) a corresponding geometric invariant. O
ften\, the ambient geometric space is the spectrum of the cohomology ring
of G\, and the geometric invariants are defined in terms of the action of
the cohomology ring on other extension groups. These geometric invariants
may then encode interesting aspects of the module category\, such as wheth
er or not a module is projective. In some situations\, support varieties a
re known to classify the thick tensor ideals in the ambient stable module
category. In this talk I’ll give an overview of support varieties in the
context of Lie superalgebras (both restricted and non-restricted) and fin
ite supergroup schemes over fields of positive characteristic.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Finkelberg (National Research University Higher School of
Economics)
DTSTART:20220601T132000Z
DTEND:20220601T142000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/38
DESCRIPTION:by Michael Finkelberg (National Research University Higher Sch
ool of Economics) as part of STARS: Superalgebra Theory and Representation
s Seminar\n\n\nAbstract\nThis is part of the Summer STARS workshop.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/38/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ian Musson (University of Wisconsin-Milwaukee)
DTSTART:20220406T161500Z
DTEND:20220406T173000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/39
DESCRIPTION:Title: On the geometry of algebras related to the Weyl groupoid
\nby Ian Musson (University of Wisconsin-Milwaukee) as part of STARS:
Superalgebra Theory and Representations Seminar\n\n\nAbstract\nLet $\\math
tt{k}$ be an algebraically closed field of characteristic zero. Let $\\ma
thfrak{g}$ be a finite dimensional classical simple Lie superalgebra over
$\\mathtt{k}$ or $\\mathfrak{gl}(m\,n)$. In the case that $\\mathfrak{g}$
is a Kac-Moody algebra of finite type with set of roots $R$\, Sergeev and
Veselov introduced the \nWeyl groupoid $\\mathfrak{W}(R)$\, which has sig
nificant connections with the representation theory of $\\mathfrak{g}$. Le
t $\\mathfrak{h}$\, $W$\, $Z(\\mathfrak{g})$ and $G_0$ be a Cartan subalge
bra of $\\mathfrak{g}_0$\, the Weyl group of $\\mathfrak{g}_0$\, the cente
r of $U(\\mathfrak{g})$ respectively and a connected\, simply connected al
gebraic group with Lie $G_0 =\\mathfrak{g}_0$. There are two important\nco
mmutative algebras related to $\\mathfrak{W}(R)$. Namely\n \n\n$\\bullet$
The image $I(\\mathfrak{h})$ of the injective Harish-Chandra map $Z(\\mat
hfrak{g})\\longrightarrow S(\\mathfrak{h})^W$.\n\n\n$\\bullet$ The superch
aracter $\\Z$-algebra $J(\\mathfrak{g})$ of finite dimensional representat
ions of $\\mathfrak{g}$.\n\n\nLet $\\mathcal A = \\mathcal A(\\mathfrak{g}
)$ be denote either $I(\\mathfrak{h})$ or $J(\\mathfrak{g}) \\otimes_{\\Z}
\\mathtt{k}$. \nThe purpose of this talk \n is to investigate the algebra
ic geometry of $\\mathcal A.$\n As a work in progress we give compelling
evidence for two geometric assertions. \nFirst\, the algebra $\\mathcal A
$ satisfies \na Nullstellensatz. (If $\\mathcal A = I(\\mathfrak{h})$\,
we assume $\\mathfrak{g} \\neq P(n)$). This gives a bijection between ra
dical ideals in $\\mathcal A$ and superalgebraic sets (zero loci of such i
deals).\nThe Nullstellensatz is proved using the Duflo-Serganova functor
which induces a map $\\mathcal A(\\mathfrak{g})\\longrightarrow\\mathcal A
(\\mathfrak{g}_x)$ where \n$\\mathfrak{g}_x$ is a Lie superalgebra of lowe
r rank.\n\n Secondly\, let $\\mathbb{T}$ be a maximal torus in $G_0$. Then
\nthere are categorical and geometric quotients in the category of $\\ma
thtt{k}$-schemes\n$$\\mathfrak{h}^*\\longrightarrow \\mathfrak{h}^*/\\math
frak{W}^c\\cong\\operatorname{Spec } I(\\mathfrak{h}) \\text{ and }\\math
bb{T} \\longrightarrow \\mathbb{T}/\\mathfrak{W}_*^c\\cong\\operatorname{S
pec } J(\\mathfrak{g}) \\otimes_{\\mathbb Z} \\mathtt{k}.$$ Here $\\mathf
rak{W}^c \\text{ and } \\mathfrak{W}_*$ are certain continuous versions of
the Weyl groupoid.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/39/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Johannes Flake (MPI Bonn)
DTSTART:20221207T170000Z
DTEND:20221207T183000Z
DTSTAMP:20260404T094937Z
UID:STARS_BGU_BIU_WIS/40
DESCRIPTION:Title: Interpolating tensor categories and their Grothendieck r
ings\nby Johannes Flake (MPI Bonn) as part of STARS: Superalgebra Theo
ry and Representations Seminar\n\n\nAbstract\nWe will review some new and
old families of (pseudo-)tensor categories which interpolate categories of
representations\, like those of symmetric or orthosymplectic groups\, inc
luding Khovanov-Sazdanovic's cobordism categories and several interpolatio
n categories introduced by Deligne. We will then describe a general techni
que to determine the indecomposable objects and an associated graded versi
on of the Grothendieck ring of such categories\, and discuss the concrete
results in some interesting examples. This is based on joint work with Rob
ert Laugwitz and Sebastian Posur.\n
LOCATION:https://stable.researchseminars.org/talk/STARS_BGU_BIU_WIS/40/
END:VEVENT
END:VCALENDAR