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CALSCALE:GREGORIAN
METHOD:PUBLISH
BEGIN:VTIMEZONE
TZID:Europe/Vienna
BEGIN:DAYLIGHT
DTSTART:20240331T030000
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
TZNAME:CEST
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BEGIN:STANDARD
DTSTART:20241027T020000
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
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BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:64b9491b15a74807122127@ist.ac.at
DTSTART:20240507T163000
DTEND:20240507T173000
DESCRIPTION:Speaker: Moritz Drescher\nhosted by Robert Seiringer\nAbstract:
We consider the local perturbation of a Bose gas by an immobile impurity.
We start with the simplest case of a non-interacting gas\, for which the
Schrödinger equation can be solved explicitly. A new method is provided\,
which allows to obtain many-body observables such as the spectral functio
n. If time permits\, we will eventually discuss ongoing work on the intera
cting gas\, where a Jastrow-like ansatz hints at an anomalous scaling of t
he ground-state energy
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Moritz Drescher: The Bose gas with a short-range impurity potential
URL:https://talks-calendar.ista.ac.at/events/4946
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:648ae9a96382d659660509@ist.ac.at
DTSTART:20240508T140000
DTEND:20240508T160000
DESCRIPTION:Speaker: Leonid Monin\nhosted by Tamas Hausel\nAbstract: A clas
sical construction associates a Poincar duality algebra to a homogeneous p
olynomial on a vector space. This construction was used to give a presenta
tion for cohomology rings of complete smooth toric varieties by Khovanskii
and Pukhlikov and of some spherical varieties (including full flag variet
ies) by Kaveh. More recently\, motivated by this construction\, Brndn and
Huh defined Lorenzian polynomials.In my talk\, I will recall the above res
ults and will give two recent generalizations of the construction of duali
ty algebras. The first one replaces the homogeneous polynomial by weighted
homogeneous polynomial (and more general functions). In contrast to the c
lassical construction\, this allows us to construct Poincar duality algebr
as which are not necessarily generated in degree 1. The second extension i
s the discrete analogue of the classical construction\, which associates a
n algebra with Gorenstein duality to a polynomial on a lattice (free abeli
an group). As a corollary\, this provides a presentation of K-ring of smoo
th complete toric varieties as well as full flag varieties.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Leonid Monin: Discrete and continues duality algebras
URL:https://talks-calendar.ista.ac.at/events/4945
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:64b9491b15a7a344471097@ist.ac.at
DTSTART:20240514T161500
DTEND:20240514T171500
DESCRIPTION:Speaker: David Padilla-Garza\nhosted by Julian Fischer\nAbstrac
t: This talk will be about an interacting particle system driven by two fo
rces: a repulsive pairwise interaction between them\, and a confining pote
ntial. At a positive temperature\, their behavior is driven by the Gibbs m
easure associated with this Hamiltoninan. We will be interested in the rat
e of convergence to the mean-field limit as the number of particles tends
to infinity. To this end\, we will formulate and prove concentration inequ
alities. We will be interested in three cases: a Coulomb interaction\, a R
iesz-type interaction\, and a general interaction.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:David Padilla-Garza: Concentration of measure in interacting partic
le systems
URL:https://talks-calendar.ista.ac.at/events/4924
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:1715857200@ist.ac.at
DTSTART:20240516T130000
DTEND:20240516T150000
DESCRIPTION:Speaker: Ngo Bao Chau\nhosted by Tamas Hausel\nAbstract: I will
describe the integral transforms on the Steinberg-Hitchin base that give
rise to the projectors in the Bernstein decomposition of the stable cocent
er of SL(2\, F) where F is a nonarchimedean local field.
LOCATION:Heinzel Seminar Room (I21.EG.101)\, Office Building West\, ISTA\,
ISTA
ORGANIZER:birgit.oosthuizen-noczil@ist.ac.at
SUMMARY:Ngo Bao Chau: On the Bernstein decomposition of the stable cocenter
URL:https://talks-calendar.ista.ac.at/events/4966
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:648ae47505085426267683@ist.ac.at
DTSTART:20240523T130000
DTEND:20240523T150000
DESCRIPTION:Speaker: Elyes Boughattas\nhosted by Tim Browning\nAbstract: De
termining whether a given diophantine equation has a solution is a wide op
en question in number theory. For some varieties -- e.g. quadrics -- the e
xistence of local points is enough to determine the existence of global po
ints: this is known as the Hasse principle. Nevertheless\, the latter does
not hold for cubic forms\, as shown by Selmer in 1951. Manin introduced i
n 1970 a set called the Brauer-Manin set\, which is expected to describe a
ll obstructions to the Hasse principle\, at least for the wide family of r
ationally connected varieties.In this talk\, I shall present a work in pro
gress which explains how this Brauer-Manin setting is related to fibration
s over P^1\, whenever the base field is the function field of a curve over
a large finite field.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Elyes Boughattas: Fibration method over F_q(t)
URL:https://talks-calendar.ista.ac.at/events/4970
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:64b9491b15a88591585873@ist.ac.at
DTSTART:20240528T163000
DTEND:20240528T173000
DESCRIPTION:Speaker: Lorenzo Dello Schiavo\nhosted by Jan Maas\nAbstract: L
et W be a conservative\, ergodic Markov diffusion on some arbitrary state
space M\, converging exponentially fast to equilibrium. We consider: (1) S
ystems of up to countably many massive particles in M\, with finite total
mass. Each particle is subject to an independent instance of the noise W\,
with volatility the inverse mass carried by the particle. We prove that t
he corresponding infinite system of SDEs has a unique solution\, for every
starting configuration and every distribution of the masses in the infini
te simplex. (2) Solutions to the Dean--Kawasaki SPDE with singular drift\,
driven by the generator L of W. We prove that the equation may be given r
igorous meaning on M\, and that it has a unique distributional solution. T
his extends Konarovskyi--Lehmann--von Renesse's ill-posedness vs. triviali
ty' to the case of infinitely many massive particles.(3) Diffusions with v
alues in the space P of all probability measures on M\, driven by the geom
etry induced by L.(4) In the case when M is a manifold\, differential-geom
etric and metric-measure Brownian motions on P induced by the geometry of
optimal transportation and reversible for a normalized completely random m
easure.We show that all these objects coincide.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Lorenzo Dello Schiavo: Massive Particle Systems\, Wasserstein Brown
ian Motions\, and the Dean--Kawasaki SPDE
URL:https://talks-calendar.ista.ac.at/events/4973
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:662261545ace7903400721@ist.ac.at
DTSTART:20240603T154500
DTEND:20240603T164500
DESCRIPTION:Speaker: Sunil Chhita\nhosted by Laszlo Erdös\, Jan Maas\nAbst
ract: The two-periodic Aztec diamond is a random tiling model which featur
es three macroscopic regions known as frozen\, rough and smooth\, which ar
e each characterized by their decay of correlations. In this talk\, we w
ill introduce the model as well as describe the behavior at the rough-smoo
th boundary. This talk is based on joint work with Duncan Dauvergne and
Thomas Finn.
LOCATION:Central Bldg / O1 / Mondi 2a (I01.O1.008)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Sunil Chhita: The two-periodic Aztec diamond
URL:https://talks-calendar.ista.ac.at/events/4937
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:662261923a2cb478035660@ist.ac.at
DTSTART:20240603T170000
DTEND:20240603T180000
DESCRIPTION:Speaker: Yuansi Chen\nhosted by Laszlo Erdös\, Jan Maas\nAbstr
act: We introduce localization schemes for analyzing the mixing time of Ma
rkov chains on continuous space and discrete hypercube. A localization sch
eme assigns every probability measure a martingale of probability measures
which localize in space as time evolves. The use of localization schemes
allows us to reduce the mixing time analysis on the original target distri
bution to that on many simpler transformed distributions.After reviewing i
ts connection to the existing literature on high dimensional concentration
and convex geometry\, we first explain Eldan's stochastic localization on
Euclidean space. Next\, we demonstrate how stochastic localization can be
used for sampling Ising models in the uniqueness regime on the discrete h
ypercube\, and discuss the differences between working on discrete and con
tinuous spaces. This observation regarding the differences motivates us to
introduce new Poisson-process-driven negative fields localization schemes
for analyzing Glauber dynamics for sampling the hardcore model.
LOCATION:Central Bldg / O1 / Mondi 2a (I01.O1.008)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Yuansi Chen: Localization Schemes
URL:https://talks-calendar.ista.ac.at/events/4938
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:648ae47507474631359149@ist.ac.at
DTSTART:20240613T130000
DTEND:20240613T150000
DESCRIPTION:Speaker: Mark Shusterman\nhosted by Tim Browning\nAbstract: We
discuss the problem of counting G-extensions of the rational numbers\, and
of a rational function field (over a finite filed)\, ramified at the smal
lest possible number of places\, for various finite groups G. This discuss
ion will take us on a tour through parameterizations of number fields\, th
e quadratic large sieve\, homology of configuration spaces\, and permutati
on groups.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Mark Shusterman: Counting Minimally Ramified Global Fields
URL:https://talks-calendar.ista.ac.at/events/5035
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:64b9491b15a9b629037551@ist.ac.at
DTSTART:20240618T163000
DTEND:20240618T173000
DESCRIPTION:Speaker: Christiaan van de Ven\nhosted by Robert Seiringer\nAbs
tract: In this seminar I present a study on the dynamics of classical infi
nite particle systems describing harmonic oscillators interacting with arb
itrarily many neighbors on lattices\, as well on more general structures\;
and I show that this enables the construction of C*-dynamical systems. Th
is approach allows particles with varying masses\, varying frequencies\, i
rregularly placed lattice sites and varying interactions subject to a simp
le summability constraint. A key role is played by the commutative resolve
nt algebra\, which is a C*-algebra of bounded continuous functions on an i
nfinite dimensional vector space\, and in a strong sense the classical lim
it of the Buchholz-Grundling resolvent algebra\, which suggests that quant
um analogs of our results are likely to exist. For a general class of Hami
ltonian dynamics\, it is demonstrated that this algebra is time-stable\, a
nd admits a time-stable sub-algebra on which the dynamics is strongly cont
inuous\, therefore obtaining a C*-dynamical system. Joint work with van Nu
land (TU Delft)
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Christiaan van de Ven: Classical dynamics of infinite particle syst
ems in an operator algebraic framework
URL:https://talks-calendar.ista.ac.at/events/4975
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:64ba3fae81177431072942@ist.ac.at
DTSTART:20240618T173000
DTEND:20240618T183000
DESCRIPTION:Speaker: Matt Kwan\nhosted by Laszlo Erdös\nAbstract: For two
independent random vectors x\,y on the n-simplex\, what is the probability
that x and y are comparable in the majorisation order? For different dist
ributions of x and y\, this question has been (independently) studied in p
robabilistic combinatorics and in quantum information theory. In particula
r\, with an appropriate distribution for x and y\, this is equivalent to s
tudying the probability that for two randomly entangled quantum states psi
and phi\, it is possible to transform phi into psi via local operations a
nd classical communication. With Vishesh Jain and Marcus Michelen\, we pro
ved a conjecture of Nielsen\, and some related predictions of Cunden\, Fac
chi\, Florio and Gramegna\, in this direction.In this seminar I plan to in
troduce the subject\, outline our proof of Nielsen's conjecture\, and ment
ion some open problems.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Matt Kwan: Entangled states are typically incomparable
URL:https://talks-calendar.ista.ac.at/events/5051
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:648ae47508072675168704@ist.ac.at
DTSTART:20240620T130000
DTEND:20240620T143000
DESCRIPTION:Speaker: Jacinta Perez Gavilan Torres\nhosted by Tamas Hausel\n
Abstract: Kostka-Foulkes polynomials are q-analogues of weight multiplicit
ies for irreducible representations of semi-simple finite-dimensional comp
lex Lie algebras. They appear in various contexts in representation theory
\; in particular they are affine Kazdhan-Lusztig polynomials and therefore
have positive coefficients. In type A\, that is\, for the special linear
Lie algebra\, a positive combinatorial formula has been known since 1978.
However\, in general\, the problem is still wide open. I will give a histo
rical introduction to the problem of finding a positive combinatorial form
ula for Kostka-Foulkes polynomials beyond type A. Then I will present some
joint results with Leonardo Patimo in this direction - in particular such
a formula for type B2/C2.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Jacinta Perez Gavilan Torres: Atoms and charge beyond type A
URL:https://talks-calendar.ista.ac.at/events/4983
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:66607019abde7795333297@ist.ac.at
DTSTART:20240620T143000
DTEND:20240620T160000
DESCRIPTION:Speaker: Leonardo Patimo\nhosted by Tamas Hausel\nAbstract: One
of the most fundamental problems in representation theory is computing th
e dimensions of the weight spaces of the irreducible representations of gr
oups. For reductive groups (such as GL_n(C))\, many combinatorial models a
ddress this question\, for example by counting the number of semistandard
tableaux.The dimensions of the weight spaces of irreducible representation
s of reductive groups have a natural q-deformation\, known as the Kostka-F
oulkes polynomials. However\, finding combinatorial statistics that expres
s these polynomials remains a long-standing open problem in algebraic comb
inatorics\, which has only been solved for type A. We develop a new approa
ch based on the geometry of the affine Grassmannian\, constructing the cha
rge in terms of the associated crystal graph. This approach not only recov
ers the results of Lascoux and Schtzenberger in type A geometrically but a
lso provides a framework to find charge statistics in general.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Leonardo Patimo: A geometric approach to the charge statistics
URL:https://talks-calendar.ista.ac.at/events/5044
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:648ae47508c71361463092@ist.ac.at
DTSTART:20240627T130000
DTEND:20240627T150000
DESCRIPTION:Speaker: Julian Demeio\nhosted by Tim Browning\nAbstract: Let $
K$ be a number field. The Grunwald problem for a finite group (scheme) G/K
asks what is the closure of the image of $H^1(K\,G) \\to \\prod_{v \\in M
_K} H^1(K_v\,G)$. For a general $G$\, there is a BrauerManin obstruction t
o the problem\, and this is conjectured to be the only one. In 2017\, Harp
az and Wittenberg introduced a technique that managed to give a positive a
nswer (BMO is the only one) for supersolvable groups. I will present a new
fibration theorem over quasi-trivial tori that\, combined with the approa
ch of Harpaz and Wittenberg\, gives a positive answer for all solvable gro
ups. Partial results were also obtained independently by Harpaz and Witten
berg.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:boosthui@ist.ac.at
SUMMARY:Julian Demeio: The Grunwald Problem for solvable groups
URL:https://talks-calendar.ista.ac.at/events/5077
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20240806T010623Z
UID:666826f557be0930623296@ist.ac.at
DTSTART:20240701T110000
DTEND:20240701T120000
DESCRIPTION:Speaker: Venkatesan Guruswami\nhosted by Marco Mondelli\nAbstra
ct: Computational problems exhibit a diverse range of behaviors in terms o
f how quickly and effectively they can be solved. What underlying mathemat
ical structure (or lack thereof) in a computational problem leads to an ef
ficient algorithm for solving it (or dictates its intractability)? Given t
he vast landscape of problems and algorithmic approaches\, it would be sim
plistic to hope for a universal theory explaining the underpinnings of eas
iness/hardness. Yet\, in the realm of constraint satisfaction problems (CS
P)\, the algebraic dichotomy theorem gives a definitive answer: a polynomi
al time algorithm exists when there are non-trivial local operations calle
d polymorphisms under which the solution space is closed\; otherwise the p
roblem is NP-complete.Inspired and emboldened by this\, one might speculat
e a polymorphic principle in more general contexts\, with symmetries in th
e solution space governing efficient algorithms. Beginning with some backg
round on CSP and the polymorphic approach to understanding their complexit
y\, the talk will discuss some extensions beyond CSP where the polymorphic
principle seems promising (yet far from understood). In particular\, we w
ill discuss promise CSP'' (PCSP) where one is allowed to satisfy a relaxed
version of the constraints (a framework that includes important problems
like approximate graph coloring). We will provide glimpses of the emerging
polymorphic theory characterizing the (in)tractability of interesting cla
sses of PCSP as well as the ability of natural classes of algorithms to so
lve them.
LOCATION:Office Bldg West / Ground floor / Heinzel Seminar Room (I21.EG.101
)\, ISTA
ORGANIZER:jdeanton@ist.ac.at
SUMMARY:Venkatesan Guruswami: When and why do efficient algorithms exist (f
or constraint satisfaction and beyond)?
URL:https://talks-calendar.ista.ac.at/events/5072
END:VEVENT
END:VCALENDAR