BEGIN:VCALENDAR
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PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Monica Nevins (University of Ottawa)
DTSTART;VALUE=DATE-TIME:20210225T230000Z
DTEND;VALUE=DATE-TIME:20210226T003000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
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 Algebra Seminar (presented by SMRI)\n\n
\nAbstract\nMonica Nevins (University of Ottawa)\n\nFriday 26th February\n
\n10:00am - 11:30am (AEDT)\n\n(Other time zones: Thur 11:00pm GMT / Fri 12
:00am CET / Thur 3:00pm PST / Thur 6:00pm EST / Fri 7:00am CST (China))\n\
nOnline via Zoom\n\nAbstract: The theory of complex representations of p-a
dic 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
open questions in\, the representation theory of G\, through the lens of r
estricting these representations to maximal compact open subgroups. Our po
int of departure: the Bruhat-Tits building of G\, a 50-year-old combinator
ial and geometric object that continues to reveal secrets about the struct
ure and representation theory of G today.\n\nRegister here: https://uni-sy
dney.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:20220927T053043Z
UID:SAGO/2
DESCRIPTION:Title: ‘
Representation theory of exceptional Lie superalgebras\nby Shun-Jen Ch
eng (Institute of Mathematics\, Academia Sinica) as part of Algebra Semina
r (presented by SMRI)\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:20220927T053043Z
UID:SAGO/3
DESCRIPTION:Title: Adv
ertising symmetric quivers and their representations\nby Magdalena Boo
s (Ruhr-University Bochum) as part of Algebra Seminar (presented by SMRI)\
n\nAbstract: 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:20220927T053043Z
UID:SAGO/4
DESCRIPTION:Title: 'Ge
ometric Satake over KU'\nby Gus Lonergan (A Priori Investment Manageme
nt LLC) as part of Algebra Seminar (presented by SMRI)\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:20220927T053043Z
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 Algebra Seminar (presented by SMRI)\n\n\nAbstract\nAbstra
ct: Over the past two decades\, there has been much progress on the classi
fication of symplectic linear quotient singularities V/G admitting a sympl
ectic (equivalently\, crepant) resolution of singularities. The classifica
tion is almost complete but there is an infinite series of groups in dimen
sion 4 - the symplectically primitive but complex imprimitive groups - and
10 exceptional groups up to dimension 10\, for which it is still open. Re
cently\, we have proven that for all but possibly 39 cases in the remainin
g infinite series there is no symplectic resolution. We have thereby reduc
ed the classification problem to finitely many open cases. We do not expec
t any of the remaining cases to admit a symplectic resolution. This is joi
nt 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:20220927T053043Z
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 Algebra Semi
nar (presented by SMRI)\n\n\nAbstract\nThis is a joint work with Samuel Je
ralds. Let gg be an affine Kac-Moody Lie algebra and let λ\, µ be two do
minant integral weights for g. We prove that under some mild restriction\,
for any positive root β\, V(λ) ⊗ V(µ) contains V(λ + µ - β) as a
component\, where V(λ) denotes the integrable highest weight (irreducible
) g-module with highest weight λ. This extends the corresponding result b
y Kumar from the case of finite dimensional semisimple Lie algebras to the
affine Kac-Moody Lie algebras. One crucial ingredient in the proof is the
action of Virasoro algebra via the Goddard-Kent-Olive construction on the
tensor product V(λ) ⊗ V(µ). Then\, we prove the corresponding geometr
ic results including the higher cohomology vanishing on the G-Schubert var
ieties in the product partial flag variety G/P × G/P with coefficients in
certain sheaves coming from the ideal sheaves of G-sub Schubert varieties
. This 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:20220927T053043Z
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 Algebra Seminar (p
resented by SMRI)\n\n\nAbstract\nLet G(ℂ) be a complex reductive group a
nd 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. Thi
s group is called the Tits group and provides a nice lifting of W. In thi
s talk\, 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 l
ifting of the Iwahori-Weyl group of G. I will show that the Tits group exi
sts 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 Ti
ts group does not exist. Finally\, as an application\, we will provide a n
ice presentation of the Hecke algebra of the p-adic group G with In-level
structure. Based on the recent joint work with Ganapathy (arXiv:2107.0176
8).\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:20220927T053043Z
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 Algebra Semi
nar (presented by SMRI)\n\n\nAbstract\nThe totally asymmetric simple exclu
sion process (TASEP) was introduced around 1970 as a model for translation
in protein synthesis and traffic flow. It has interesting physical proper
ties (e.g. boundary-induced phase transitions) and also beautiful mathemat
ical properties. The inhomogeneous TASEP is a Markov chain of weighted par
ticles hopping on a ring\, in which the probability that two particles int
erchange depends on the weight of those particles. If each particle has a
distinct weight\, then we can think of this as a Markov chain on permutati
ons. In many cases\, the steady state probabilities can be expressed in te
rms 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:20220927T053043Z
UID:SAGO/9
DESCRIPTION:Title: A s
ingular Coxeter presentation\nby Hankyung Ko (Uppsala University) as p
art of Algebra Seminar (presented by SMRI)\n\n\nAbstract\nSMRI Algebra and
Geometry Online\n’A singular Coxeter presentation’\nHankyung Ko (Upps
ala University)\n\nThursday\, Aug 26\n3:30pm-5:30pm (AEST)\nRegister: \nht
tps://uni-sydney.zoom.us/meeting/register/tZYqcO2uqDkpE9DpzrQ6bJCXU2M0pdUM
Xo-k \n\nAbstract: A Coxeter system is a presentation of a group by genera
tors and a specific \nform of relations\, namely the braid relations and t
he reflection relations. The \nCoxeter presentation leads to\, among other
s\, a similar presentation of the \n(Iwahori-)Hecke algebras and the Kazhd
an-Lusztig theory\, which provides combinatorial \nanswers to major proble
ms in Lie theoretic representation theory and geometry. \nExtending such a
pplications to the `singular land’ requires the singular version of \nth
e Hecke algebra. Underlying combinatorics of the singular Hecke algebra/ca
tegory \ncomes from the parabolic double cosets and is the first step in u
nderstanding the \nsingular Hecke category. In this talk\, I will present
a Coxeter theory of the \nparabolic double cosets developed in a joint wor
k with Ben Elias. In particular\, I \nwill explain a generalization of the
reduced expressions and describe the braid and \nnon-braid relations.\n\n
Biography: Hangyung Ko is a postdoc researcher at Matematiska institutione
n\, Uppsala \nUniversity\, working on Lie theoretic representation theory.
She is mainly interested \nin representation theory of algebraic groups i
n positive characteristic\, category O\, \nhigher(categorical) representat
ion theory\, and related topics like Coxeter groups \nand their Hecke alge
bras\, Soergel bimodules\, quantum groups\, R-matrices and \nK-matrices\,
polynomial functors and functor cohomology\, category theory and \nhomolog
ical algebra.\n\nNote: These seminars will be recorded\, including partici
pant questions (participants \nonly when asking questions)\, and uploaded
to the SMRI YouTube Channel \nhttps://www.youtube.com/c/SydneyMathematical
ResearchInstituteSMRI \n\nOther upcoming SMRI events can be found here: \n
https://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:20220927T053043Z
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 Algebra Seminar (presented by SMRI)
\n\n\nAbstract\nAbstract: The cohomology ring H^*(BG) (with coefficients i
n 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)\
, which 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\nThis leads one to study C^*(BG) as if it was a commutative local Noethe
rian ring\, though of course one has to use homotopy invariant methods. Th
e ring C^*(BG) is regular if and only if G is p-nilpotent and so it is nat
ural to look for ways of deciding where C^*(BG) lies on the spectrum betwe
en regular and Gorenstein rings. For a commutative Noetherian ring\, one c
onsiders the singularity category D_{sg}(R) (the quotient of finite comple
xes of finitely generated modules by finitely generated projectives). This
is trivial if and only if R is regular\, so is the appropriate tool. The
talk will describe how to define this for C^*(BG)\, show it has good basic
properties 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:20220927T053043Z
UID:SAGO/11
DESCRIPTION:Title: So
lving semidecidable problems in group theory\nby Giles Gardam (Univers
ity of Münster) as part of Algebra Seminar (presented by SMRI)\n\n\nAbstr
act\nGroup theory is littered with undecidable problems. A classic example
is the word problem: there are groups for which there exists no algorithm
that can decide if a product of generators represents the trivial element
or not. Many problems (the word problem included) are at least semidecida
ble\, meaning that there is a correct algorithm guaranteed to terminate if
the answer is "yes"\, but with no guarantee on how long one has to wait.
I will discuss strategies to try and tackle various semidecidable problems
computationally with the key example being the discovery of a counterexam
ple to the Kaplansky unit conjecture.\n\nBiography: Giles Gardam is a rese
arch associate at the University of Münster working in geometric group th
eory. He studied mathematics and computer science at the University of Syd
ney\, receiving his Bachelor's degree in 2012\, and completed his doctorat
e at 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/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Joel Kamnitzer (University of Toronto)
DTSTART;VALUE=DATE-TIME:20211020T230000Z
DTEND;VALUE=DATE-TIME:20211021T003000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
UID:SAGO/12
DESCRIPTION:Title: Sy
mplectic duality and (generalized) affine Grassmannian slices\nby Joel
Kamnitzer (University of Toronto) as part of Algebra Seminar (presented b
y SMRI)\n\n\nAbstract\nUnder the geometric Satake equivalence\, slices in
the affine Grassmannian give\na geometric incarnation of dominant weight s
paces in representations of reductive\ngroups. These affine Grassmannian
slices are quantized by algebras known as truncated\nshifted Yangians. Fr
om this perspective\, we expect to categorify these weight spaces\nusing c
ategory O for these truncated shifted Yangians. \n\nThe slices in the aff
ine Grassmannian and truncated shifted Yangians can also be defined\nas sp
ecial cases of the Coulomb branch construction of Braverman-Finkelberg-Nak
ajima.\nFrom this perspective\, we find many insights. First\, we can gen
eralize affine\nGrassmannian slices to the case of non-dominant weights an
d arbitrary symmetric\nKac-Moody Lie algebras. Second\, we establish a li
nk with modules for KLRW algebras.\nFinally\, we defined a categorical g-a
ction on the categories O\, using Hamiltonian\nreduction.\n
LOCATION:https://researchseminars.org/talk/SAGO/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jack Morava (Johns Hopkins University)
DTSTART;VALUE=DATE-TIME:20211110T230000Z
DTEND;VALUE=DATE-TIME:20211111T003000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
UID:SAGO/13
DESCRIPTION:Title: On
the group completion of the Burau representation\nby Jack Morava (Joh
ns Hopkins University) as part of Algebra Seminar (presented by SMRI)\n\n\
nAbstract\nOn fundamental groups\, the discriminant \\prod_{i \\neq k} (z_
i - z_k) \\in \\C^\\times of a finite collection of points of the plane de
fines the abelianization homomorphism sending a braid to its number of ove
rcrossings less undercrossings or writhe. In terms of diffeomorphisms of t
he punctured plane\, it defines a kind of `invertible topological quantum
field theory' associated to the Burau representation\, and in the classica
l physics of point particles the real part of its logarithmic derivative i
s the potential energy of a collection of Coulomb charges\, while its imag
inary part is essentially the Nambu-Goto area of a loop of string in the t
hree-sphere. \n \nIts higher homotopy theory defines a very interesting a
double-loop map \n\\Z \\times \\Omega^2 S^3 \\to \\Pic(S^0)\nto the cate
gory of lines over the stable homotopy ring-spectrum\, related to Hopkins
and Mahowald's exotic (E_2) multiplication on classical integral homology\
, perhaps related to the `anyons' of nonclassical physics.\n\n(based on jo
int work with D Rolfsen)\n
LOCATION:https://researchseminars.org/talk/SAGO/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shane Kelly (Tokyo Institute of Technology)
DTSTART;VALUE=DATE-TIME:20211202T040000Z
DTEND;VALUE=DATE-TIME:20211202T053000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
UID:SAGO/14
DESCRIPTION:Title: Bl
owup formulas for nilpotent sensitive cohomology theories\nby Shane Ke
lly (Tokyo Institute of Technology) as part of Algebra Seminar (presented
by SMRI)\n\n\nAbstract\nThis is joint work in progress with Shuji Saito. M
any cohomology theories of interest (l-adic cohomology\, de Rham cohomolog
y\, motivic cohomology\, K-theory...) have long exact sequences associated
to blowups. Such a property can be neatly encoded in a Grothendieck topol
ogy such as the cdh-topology or the h-topology. These topologies appeared
in Voevodsky's proof of the Bloch-Kato conjecture\, and more recently in B
eilinson's simple proof of Fontaine's CdR conjecture\, and in Bhatt and Sc
holze's work on projectivity of the affine Grassmanian.\n\nA feature of th
ese topologies which often turns out to be a bug is that the associated sh
eaves cannot see nilpotents. In this talk I will discuss a modification wh
ich can see nilpotents\, and which still has long exact sequences for many
blowups.\n
LOCATION:https://researchseminars.org/talk/SAGO/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sang-hyun Kim (Korea Institute for Advanced Study)
DTSTART;VALUE=DATE-TIME:20220302T020000Z
DTEND;VALUE=DATE-TIME:20220302T033000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
UID:SAGO/15
DESCRIPTION:Title: Op
timal regularity of mapping class group actions on the circle\nby Sang
-hyun Kim (Korea Institute for Advanced Study) as part of Algebra Seminar
(presented by SMRI)\n\n\nAbstract\nWe prove that for each finite index sub
group H of the mapping class group of a \nclosed hyperbolic surface\, and
for each real number r>1 there does not exist a faithful \nC^r-action (in
Hoelder’s sense) of H on a circle. For this\, we partially determine the
\noptimal regularity of faithful actions by right-angled Artin groups on
a circle. (Joint \nwith Thomas Koberda and Cristobal Rivas).\n
LOCATION:https://researchseminars.org/talk/SAGO/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Monica Vazirani (University of California\, Davis))
DTSTART;VALUE=DATE-TIME:20220414T000000Z
DTEND;VALUE=DATE-TIME:20220414T013000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
UID:SAGO/16
DESCRIPTION:Title: Fr
om representations of the rational Cherednik algebra to parabolic Hilbert
schemes via the Dunkl-Opdam subalgebra\nby Monica Vazirani (Universit
y of California\, Davis)) as part of Algebra Seminar (presented by SMRI)\n
\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/SAGO/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Will Donovan (Tsinghua University)
DTSTART;VALUE=DATE-TIME:20220923T020000Z
DTEND;VALUE=DATE-TIME:20220923T030000Z
DTSTAMP;VALUE=DATE-TIME:20220927T053043Z
UID:SAGO/17
DESCRIPTION:Title: Ho
mological comparison of resolution and smoothing\nby Will Donovan (Tsi
nghua University) as part of Algebra Seminar (presented by SMRI)\n\nLectur
e held in Carslaw 173.\n\nAbstract\nAbstract: A singular space often comes
equipped with (1) a resolution\, given by a morphism from a smooth space\
, and (2) a smoothing\, namely a deformation with smooth generic fibre. I
will discuss work in progress on how these may be related homologically\,
starting with the threefold ordinary double point as a key example.\n
LOCATION:https://researchseminars.org/talk/SAGO/17/
END:VEVENT
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