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BEGIN:VEVENT
SUMMARY:Monica Nevins (University of Ottawa)
DTSTART;VALUE=DATE-TIME:20210225T230000Z
DTEND;VALUE=DATE-TIME:20210226T003000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/1
DESCRIPTION:Title: Cha
racters and types: the personality of a representation of a p-adic group\,
revealed by branching to its compact open subgroups\nby Monica Nevins
(University of Ottawa) as part of SMRI Algebra and Geometry Online\n\n\nA
bstract\nMonica Nevins (University of Ottawa)\n\nFriday 26th February\n\n1
0:00am - 11:30am (AEDT)\n\n(Other time zones: Thur 11:00pm GMT / Fri 12:00
am CET / Thur 3:00pm PST / Thur 6:00pm EST / Fri 7:00am CST (China))\n\nOn
line via Zoom\n\nAbstract: The theory of complex representations of p-adic
groups can feel very technical and unwelcoming\, but its central role in
the conjectural local Langlands correspondence has pushed us to pursue its
understanding. In this talk\, I will aim to share the spirit of\, and ope
n questions in\, the representation theory of G\, through the lens of rest
ricting these representations to maximal compact open subgroups. Our point
of departure: the Bruhat-Tits building of G\, a 50-year-old combinatorial
and geometric object that continues to reveal secrets about the structure
and representation theory of G today.\n\nRegister here: https://uni-sydne
y.zoom.us/meeting/register/tZUrd--uqj0iHNcugXMnXTmSQfZVh08zruaN\n
LOCATION:https://researchseminars.org/talk/SAGO/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shun-Jen Cheng (Institute of Mathematics\, Academia Sinica)
DTSTART;VALUE=DATE-TIME:20210506T053000Z
DTEND;VALUE=DATE-TIME:20210506T070000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/2
DESCRIPTION:Title: ‘
Representation theory of exceptional Lie superalgebras\nby Shun-Jen Ch
eng (Institute of Mathematics\, Academia Sinica) as part of SMRI Algebra a
nd Geometry Online\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SAGO/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Magdalena Boos (Ruhr-University Bochum)
DTSTART;VALUE=DATE-TIME:20210617T053000Z
DTEND;VALUE=DATE-TIME:20210617T070000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/3
DESCRIPTION:Title: Adv
ertising symmetric quivers and their representations\nby Magdalena Boo
s (Ruhr-University Bochum) as part of SMRI Algebra and Geometry Online\n\n
Abstract: TBA\n
LOCATION:https://researchseminars.org/talk/SAGO/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gus Lonergan (A Priori Investment Management LLC)
DTSTART;VALUE=DATE-TIME:20210623T230000Z
DTEND;VALUE=DATE-TIME:20210624T003000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/4
DESCRIPTION:Title: 'Ge
ometric Satake over KU'\nby Gus Lonergan (A Priori Investment Manageme
nt LLC) as part of SMRI Algebra and Geometry Online\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SAGO/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ulrich Thiel (University of Kaiserslautern)
DTSTART;VALUE=DATE-TIME:20210708T053000Z
DTEND;VALUE=DATE-TIME:20210708T070000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/5
DESCRIPTION:Title: Tow
ards the classification of symplectic linear quotient singularities admitt
ing a symplectic resolution\nby Ulrich Thiel (University of Kaiserslau
tern) as part of SMRI Algebra and Geometry Online\n\n\nAbstract\nAbstract:
Over the past two decades\, there has been much progress on the classific
ation of symplectic linear quotient singularities V/G admitting a symplect
ic (equivalently\, crepant) resolution of singularities. The classificatio
n is almost complete but there is an infinite series of groups in dimensio
n 4 - the symplectically primitive but complex imprimitive groups - and 10
exceptional groups up to dimension 10\, for which it is still open. Recen
tly\, we have proven that for all but possibly 39 cases in the remaining i
nfinite series there is no symplectic resolution. We have thereby reduced
the classification problem to finitely many open cases. We do not expect a
ny of the remaining cases to admit a symplectic resolution. This is joint
work with Gwyn Bellamy and Johannes Schmitt.\n
LOCATION:https://researchseminars.org/talk/SAGO/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shrawan Kumar (University of North Carolina)
DTSTART;VALUE=DATE-TIME:20210723T010000Z
DTEND;VALUE=DATE-TIME:20210723T023000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/6
DESCRIPTION:Title: Roo
t components for tensor product of affine Kac-Moody Lie algebra modules\nby Shrawan Kumar (University of North Carolina) as part of SMRI Algebra
and Geometry Online\n\n\nAbstract\nThis is a joint work with Samuel Jeral
ds. Let gg be an affine Kac-Moody Lie algebra and let λ\, µ be two domin
ant integral weights for g. We prove that under some mild restriction\, fo
r any positive root β\, V(λ) ⊗ V(µ) contains V(λ + µ - β) as a com
ponent\, where V(λ) denotes the integrable highest weight (irreducible) g
-module with highest weight λ. This extends the corresponding result by K
umar from the case of finite dimensional semisimple Lie algebras to the af
fine Kac-Moody Lie algebras. One crucial ingredient in the proof is the ac
tion of Virasoro algebra via the Goddard-Kent-Olive construction on the te
nsor product V(λ) ⊗ V(µ). Then\, we prove the corresponding geometric
results including the higher cohomology vanishing on the G-Schubert variet
ies in the product partial flag variety G/P × G/P with coefficients in ce
rtain sheaves coming from the ideal sheaves of G-sub Schubert varieties. T
his allows us to prove the surjectivity of the Gaussian map.\n
LOCATION:https://researchseminars.org/talk/SAGO/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Xuhua He (Chinese University of Hong Kong)
DTSTART;VALUE=DATE-TIME:20210805T053000Z
DTEND;VALUE=DATE-TIME:20210805T070000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/7
DESCRIPTION:Title: Tit
s groups of Iwahori-Weyl groups and presentations of Hecke algebras\nb
y Xuhua He (Chinese University of Hong Kong) as part of SMRI Algebra and G
eometry Online\n\n\nAbstract\nLet G(ℂ) be a complex reductive group and
W be its Weyl group. In 1966\, Tits introduced a certain subgroup of G(ℂ
)\, which is an extension of W by an elementary abelian 𝟸-group. This g
roup is called the Tits group and provides a nice lifting of W. In this t
alk\, I will discuss a generalization of the notion of the Tits group 𝒯
to a reductive p-adic group G. Such 𝒯\, if exists\, gives a nice lifti
ng of the Iwahori-Weyl group of G. I will show that the Tits group exists
when the reductive group splits over an unramified extension of the p-adic
field and will provide an example in the ramified case that such a Tits g
roup does not exist. Finally\, as an application\, we will provide a nice
presentation of the Hecke algebra of the p-adic group G with In-level stru
cture. Based on the recent joint work with Ganapathy (arXiv:2107.01768).\
n
LOCATION:https://researchseminars.org/talk/SAGO/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lauren K. Williams (Harvard University)
DTSTART;VALUE=DATE-TIME:20210819T000000Z
DTEND;VALUE=DATE-TIME:20210819T010000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/8
DESCRIPTION:Title: Sch
ubert polynomials\, the inhomogeneous TASEP\, and evil-avoiding permutatio
ns\nby Lauren K. Williams (Harvard University) as part of SMRI Algebra
and Geometry Online\n\n\nAbstract\nThe totally asymmetric simple exclusio
n process (TASEP) was introduced around 1970 as a model for translation in
protein synthesis and traffic flow. It has interesting physical propertie
s (e.g. boundary-induced phase transitions) and also beautiful mathematica
l properties. The inhomogeneous TASEP is a Markov chain of weighted partic
les hopping on a ring\, in which the probability that two particles interc
hange depends on the weight of those particles. If each particle has a dis
tinct weight\, then we can think of this as a Markov chain on permutations
. In many cases\, the steady state probabilities can be expressed in terms
of Schubert polynomials. Based on joint work with Donghyun Kim.\n
LOCATION:https://researchseminars.org/talk/SAGO/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hankyung Ko (Uppsala University)
DTSTART;VALUE=DATE-TIME:20210826T053000Z
DTEND;VALUE=DATE-TIME:20210826T070000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/9
DESCRIPTION:Title: A s
ingular Coxeter presentation\nby Hankyung Ko (Uppsala University) as p
art of SMRI Algebra and Geometry Online\n\n\nAbstract\nSMRI Algebra and Ge
ometry Online\n’A singular Coxeter presentation’\nHankyung Ko (Uppsala
University)\n\nThursday\, Aug 26\n3:30pm-5:30pm (AEST)\nRegister: \nhttps
://uni-sydney.zoom.us/meeting/register/tZYqcO2uqDkpE9DpzrQ6bJCXU2M0pdUMXo-
k \n\nAbstract: A Coxeter system is a presentation of a group by generator
s and a specific \nform of relations\, namely the braid relations and the
reflection relations. The \nCoxeter presentation leads to\, among others\,
a similar presentation of the \n(Iwahori-)Hecke algebras and the Kazhdan-
Lusztig theory\, which provides combinatorial \nanswers to major problems
in Lie theoretic representation theory and geometry. \nExtending such appl
ications to the `singular land’ requires the singular version of \nthe H
ecke algebra. Underlying combinatorics of the singular Hecke algebra/categ
ory \ncomes from the parabolic double cosets and is the first step in unde
rstanding the \nsingular Hecke category. In this talk\, I will present a C
oxeter theory of the \nparabolic double cosets developed in a joint work w
ith Ben Elias. In particular\, I \nwill explain a generalization of the re
duced expressions and describe the braid and \nnon-braid relations.\n\nBio
graphy: Hangyung Ko is a postdoc researcher at Matematiska institutionen\,
Uppsala \nUniversity\, working on Lie theoretic representation theory. Sh
e is mainly interested \nin representation theory of algebraic groups in p
ositive characteristic\, category O\, \nhigher(categorical) representation
theory\, and related topics like Coxeter groups \nand their Hecke algebra
s\, Soergel bimodules\, quantum groups\, R-matrices and \nK-matrices\, pol
ynomial functors and functor cohomology\, category theory and \nhomologica
l algebra.\n\nNote: These seminars will be recorded\, including participan
t questions (participants \nonly when asking questions)\, and uploaded to
the SMRI YouTube Channel \nhttps://www.youtube.com/c/SydneyMathematicalRes
earchInstituteSMRI \n\nOther upcoming SMRI events can be found here: \nhtt
ps://mathematical-research-institute.sydney.edu.au/news-events/\n
LOCATION:https://researchseminars.org/talk/SAGO/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Greenlees (University of Warwick)
DTSTART;VALUE=DATE-TIME:20210916T060000Z
DTEND;VALUE=DATE-TIME:20210916T073000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/10
DESCRIPTION:Title: Th
e singularity category of C^*(BG) for a finite group G\nby John Greenl
ees (University of Warwick) as part of SMRI Algebra and Geometry Online\n\
n\nAbstract\nAbstract: The cohomology ring H^*(BG) (with coefficients in a
field k of characteristic p) is a very special graded commutative ring\,
but this comes out much more clearly if one uses the cochains C^*(BG)\, w
hich can be viewed as a commutative ring up to homotopy. For example C^*(
BG) is always Gorenstein (whilst this is not quite true for H^*(BG)). \n\n
This leads one to study C^*(BG) as if it was a commutative local Noetheria
n ring\, though of course one has to use homotopy invariant methods. The r
ing C^*(BG) is regular if and only if G is p-nilpotent and so it is natura
l to look for ways of deciding where C^*(BG) lies on the spectrum between
regular and Gorenstein rings. For a commutative Noetherian ring\, one cons
iders the singularity category D_{sg}(R) (the quotient of finite complexes
of finitely generated modules by finitely generated projectives). This is
trivial if and only if R is regular\, so is the appropriate tool. The tal
k will describe how to define this for C^*(BG)\, show it has good basic pr
operties and describe the singularity category in the simplest case it is
not trivial (when G has a cyclic Sylow p-subgroup).\n
LOCATION:https://researchseminars.org/talk/SAGO/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Giles Gardam (University of Münster)
DTSTART;VALUE=DATE-TIME:20211005T050000Z
DTEND;VALUE=DATE-TIME:20211005T063000Z
DTSTAMP;VALUE=DATE-TIME:20210926T132120Z
UID:SAGO/11
DESCRIPTION:Title: So
lving semidecidable problems in group theory\nby Giles Gardam (Univers
ity of Münster) as part of SMRI Algebra and Geometry Online\n\n\nAbstract
\nGroup theory is littered with undecidable problems. A classic example is
the word problem: there are groups for which there exists no algorithm th
at can decide if a product of generators represents the trivial element or
not. Many problems (the word problem included) are at least semidecidable
\, meaning that there is a correct algorithm guaranteed to terminate if th
e answer is "yes"\, but with no guarantee on how long one has to wait. I w
ill discuss strategies to try and tackle various semidecidable problems co
mputationally with the key example being the discovery of a counterexample
to the Kaplansky unit conjecture.\n\nBiography: Giles Gardam is a researc
h associate at the University of Münster working in geometric group theor
y. He studied mathematics and computer science at the University of Sydney
\, receiving his Bachelor's degree in 2012\, and completed his doctorate a
t Oxford in 2017. He was then a postdoc at the Technion before starting at
Münster in 2019.\n
LOCATION:https://researchseminars.org/talk/SAGO/11/
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