BEGIN:VCALENDAR
VERSION:2.0
PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Sobhan Seyfaddini (Sorbonne)
DTSTART;VALUE=DATE-TIME:20210913T080000Z
DTEND;VALUE=DATE-TIME:20210913T090000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/1
DESCRIPTION:Title: The algebraic structure of groups of area-preserving homeom
orphisms\nby Sobhan Seyfaddini (Sorbonne) as part of IBS-CGP weekly zo
om seminar (Fall 2021)\n\nLecture held in Zoom online.\n\nAbstract\nI will
review recent joint work with Dan Cristofaro-Gardiner\, Vincent Humilièr
e\, Cheuk Yu Mak and Ivan Smith constructing a new family of spectral inva
riants associated to certain Lagrangian links in compact and connected sur
faces of any genus. We show that our invariants recover the Calabi invaria
nt of Hamiltonians in their limit. As applications\, we resolve several op
en questions from topological surface dynamics and continuous symplectic t
opology: \n1. We show that the group of Hamiltonian homeomorphisms of any
compact surface with (possibly empty) boundary is not simple\n2. We extend
the Calabi homomorphism to the group of Hameomorphisms constructed by Oh-
Müller.\n3. We construct an infinite dimensional family of quasimorphisms
on the group of area and orientation preserving homeomorphisms of the two
-sphere. \nOur invariants are inspired by recent work of Polterovich and S
helukhin defining and applying spectral invariants for links in the two-sp
here consisting of parallel circles.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Siu-Cheong Lau (Boston)
DTSTART;VALUE=DATE-TIME:20211018T010000Z
DTEND;VALUE=DATE-TIME:20211018T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/3
DESCRIPTION:Title: Noncommutative deformations of crepant resolutions via mirr
or symmetry\nby Siu-Cheong Lau (Boston) as part of IBS-CGP weekly zoom
seminar (Fall 2021)\n\nLecture held in Zoom online.\n\nAbstract\nNoncommu
tative crepant resolutions of singularities formulated by Van den Bergh ad
mit interesting quantization deformations. On the other hand\, nc deforma
tions can also be constructed via a local-to-global approach using the not
ion of an algebroid stack. In this talk\, I will explain a mirror method
of constructing explicit nc deformed crepant resolutions\, and a Fourier-M
ukai transform between these two notions. An important ingredient is a ce
rtain class of Lagrangian objects in the mirror side\, whose (higher) morp
hisms can be found via a 3d enhancement of the corresponding objects in Ri
emann surfaces.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Anthony Gardiner (UCSC)
DTSTART;VALUE=DATE-TIME:20211101T010000Z
DTEND;VALUE=DATE-TIME:20211101T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/4
DESCRIPTION:Title: The Simplicity Conjecture\nby Daniel Anthony Gardiner (
UCSC) as part of IBS-CGP weekly zoom seminar (Fall 2021)\n\nLecture held i
n Zoom online.\n\nAbstract\nIn the 60s and 70s\, there was a flurry of act
ivity concerning the question of whether or not various subgroups of homeo
morphism groups of manifolds are simple\, with beautiful contributions by
Fathi\, Kirby\, Mather\, Thurston\, and many others. A funnily stubborn ca
se that remained open was the case of area-preserving homeomorphisms of su
rfaces. For example\, for balls of dimension at least 3\, the relevant gro
up was shown to be simple by work of Fathi from the 1970s\, but the answer
in the two-dimensional case was not known. I will explain recent joint wo
rk proving that the group of compactly supported area preserving homeomorp
hisms of the two-disc is in fact not a simple group\, which answers the "S
implicity Conjecture” in the affirmative. Our proof uses a new tool for
studying area-preserving surface homeomorphisms\, called periodic Floer ho
mology (PFH) spectral invariants\; these recover the classical Calabi inva
riant in their asymptotic limit.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kyungmin Rho (SNU (Seoul National University))
DTSTART;VALUE=DATE-TIME:20210906T010000Z
DTEND;VALUE=DATE-TIME:20210906T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/5
DESCRIPTION:Title: Mirror Symmetry Correspondence between Indecomposable Cohen
-Macaulay Modules over Degenerate Cusps and Immersed Lagrangians on Surfac
es\nby Kyungmin Rho (SNU (Seoul National University)) as part of IBS-C
GP weekly zoom seminar (Fall 2021)\n\nLecture held in Zoom online.\n\nAbst
ract\nBurban and Drozd (2017) classified all indecomposable maximal Cohen-
Macaulay modules over degenerate cusps. For the degenerate cusp defined by
xyz\, its mirror is given by a pair of pants (Abouzaid\, Auroux\, Efimov\
, Katzarkov and Orlov). We find explicit objects in the Fukaya category of
a pair of pants\, which correspond to every indecomposable Cohen-Macaulay
modules in Burban and Drozd's list under the localized mirror functor. Th
is is a joint work in progress with Cheol-Hyun Cho\, Wonbo Jeong and Kyoun
gmo Kim.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tobias Ekholm (Uppsala)
DTSTART;VALUE=DATE-TIME:20210927T080000Z
DTEND;VALUE=DATE-TIME:20210927T090000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/6
DESCRIPTION:Title: Skein valued curve counts\, basic holomorphic disks\, and H
OMFLY homology\nby Tobias Ekholm (Uppsala) as part of IBS-CGP weekly z
oom seminar (Fall 2021)\n\nLecture held in Zoom online.\n\nAbstract\nWe de
scribe invariant counts of holomorphic curves in a Calabi-Yau 3-fold with
boundary in a Lagrangian in the skein module of that Lagrangian. We show
how to turn this into concrete counts for the toric brane in the resolved
conifold. This leads to a notion of basic holomorphic disks for any knot c
onormal in the resolved conifold. These basic holomorphic disks seem to ge
nerate HOMFLY homology in the basic representation. We give a conjectural
description of similar holomorphic object generating parts of higher symme
tric representation HOMFLY homology and verify some predictions coming fro
m this conjecture in examples.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sheel Ganatra (USC)
DTSTART;VALUE=DATE-TIME:20211025T010000Z
DTEND;VALUE=DATE-TIME:20211025T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/7
DESCRIPTION:Title: Categorical non-properness in wrapped Floer theory\nby
Sheel Ganatra (USC) as part of IBS-CGP weekly zoom seminar (Fall 2021)\n\n
Lecture held in Zoom online.\n\nAbstract\nIn all known explicit computatio
ns on Weinstein manifolds\, the self-wrapped Floer homology of non-compact
exact Lagrangian is always either infinite-dimensional or zero. We will
explain why a global variant of this observed phenomenon holds in broad ge
nerality: the wrapped Fukaya category of any positive-dimensional Weinstei
n (or non-degenerate Liouville) manifold is always either non-proper or ze
ro\, as is any quotient thereof. Moreover any non-compact connected exact
Lagrangian is always either a "non-proper object" or zero in such a wrappe
d Fukaya category\, as is any idempotent summand thereof. We will examine
where the argument could break if one drops exactness\, which is consisten
t with known computations of non-exact wrapped Fukaya categories which are
smooth\, proper\, and non-vanishing (e.g.\, work of Ritter-Smith). We wil
l also give a perspective on the proof in terms of "properness obstruction
" invariants of certain categories\, which can be related for wrapped Fuka
ya categories to closed and open-string versions of Rabinowitz Floer theor
y (the latter by joint work in progress with Y. Gao and S. Venkatesh).\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mohammed Abouzaid (Colombia)
DTSTART;VALUE=DATE-TIME:20211108T010000Z
DTEND;VALUE=DATE-TIME:20211108T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/8
DESCRIPTION:Title: Complex cobordism and Hamiltonian fibrations\nby Mohamm
ed Abouzaid (Colombia) as part of IBS-CGP weekly zoom seminar (Fall 2021)\
n\nLecture held in Zoom online.\n\nAbstract\nI will discuss joint work wit
h McLean and Smith\, lifting the results of Seidel\, Lalonde\, and McDuff
concerning the topology of Hamiltonian fibrations over the 2-sphere from r
ational cohomology to complex cobordism. In addition to the use of Morava
K-theory (as in the recent work with Blumberg on the Arnold Conjecture)\,
the essential new ingredient is the construction of global Kuranishi chart
s of genus 0 pseudo-holomorphic curves\; i.e. their realisation as quotie
nts of zero loci of equivariant vector bundles on manifolds.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Usher (UGA)
DTSTART;VALUE=DATE-TIME:20211115T010000Z
DTEND;VALUE=DATE-TIME:20211115T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/9
DESCRIPTION:Title: Interlevel persistence and Floer theory\nby Michael Ush
er (UGA) as part of IBS-CGP weekly zoom seminar (Fall 2021)\n\nLecture hel
d in Zoom online.\n\nAbstract\nThere is a rich history in symplectic topol
ogy of using the filtration structures on Floer complexes to extract geome
trically interesting information\, in a way that formally mimics the relat
ions between the homologies of sublevel sets of a Morse function on a fini
te-dimensional manifold. In the finite-dimensional case\, it can be usefu
l to consider homologies not just of sublevel sets but of interlevel sets
(preimages of general intervals\, including singletons)\; however\, in the
Floer-theoretic context it is not so obvious what the analogue of the hom
ology of an interlevel set is. I will explain a general algebraic framewo
rk---applicable for instance to Hamiltonian Floer theory---for obtaining i
nterlevel persistence-type barcodes from the sorts of complexes that arise
in Floer theory\; these barcodes carry somewhat more information than the
more conventional sublevel persistence barcodes.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Michael Hutchings (Berkeley)
DTSTART;VALUE=DATE-TIME:20211122T010000Z
DTEND;VALUE=DATE-TIME:20211122T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/10
DESCRIPTION:Title: Smooth closing lemmas for area-preserving surface diffeomo
rphisms\nby Michael Hutchings (Berkeley) as part of IBS-CGP weekly zoo
m seminar (Fall 2021)\n\nLecture held in Zoom online.\n\nAbstract\nWe show
that an area-preserving diffeomorphism of a closed surface satisfying a "
rationality" property has the "C^\\infty closing property". The latter pro
perty asserts that for any nonempty open set\, one can make a C^\\infty sm
all Hamiltonian perturbation supported in the open set to obtain a periodi
c orbit intersecting the open set. Moreover we obtain quantitative results
\, asserting roughly speaking that during a given Hamiltonian isotopy\, wi
thin time \\delta a periodic orbit must appear of period at most O(\\delta
^{-1}). The proof uses spectral invariants in periodic Floer homology. Thi
s is a joint work with Oliver Edtmair.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tony Yue Yu (Université Paris-Sud)
DTSTART;VALUE=DATE-TIME:20211129T010000Z
DTEND;VALUE=DATE-TIME:20211129T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/11
DESCRIPTION:Title: Moduli of Calabi-Yau pairs and secondary fans\nby Tony
Yue Yu (Université Paris-Sud) as part of IBS-CGP weekly zoom seminar (Fa
ll 2021)\n\nLecture held in Zoom online.\n\nAbstract\nWe conjecture that t
he moduli space of smooth polarized Calabi-Yau pairs is unirational. More
precisely\, we consider its natural compactification inside the KSBA stabl
e pair moduli space\, and conjecture that the compactification admits a fi
nite cover by a complete toric variety. We construct the associated comple
te toric fan\, generalizing the Gelfand-Kapranov-Zelevinski secondary fan
for reflexive polytopes. Inspired by mirror symmetry\, we speculate a synt
hetic construction of the universal family over this toric variety\, as th
e Proj of a sheaf of graded algebras with a canonical basis\, whose struct
ure constants are given by counts of non-archimedean analytic disks. In th
e Fano case and under the assumption that the mirror variety contains a Za
riski open torus\, we construct the conjectural universal family\, general
izing the families of Kapranov-Sturmfels-Zelevinski and Alexeev in the tor
ic case. In the case of del Pezzo surfaces with an anti-canonical cycle of
(-1)-curves\, we prove the full conjecture. Joint work with Hacking and K
eel.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeffrey Carlson (Imperial College London)
DTSTART;VALUE=DATE-TIME:20211206T080000Z
DTEND;VALUE=DATE-TIME:20211206T090000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/12
DESCRIPTION:Title: The topology of the Gelfand–Zeitlin fiber\nby Jeffre
y Carlson (Imperial College London) as part of IBS-CGP weekly zoom seminar
(Fall 2021)\n\nLecture held in Zoom online.\n\nAbstract\nGelfand–Zeitli
n systems are a well-known family of examples in symplectic geometry\, sin
gular Lagrangian torus fibrations whose total spaces are coadjoint orbits
of an action of a unitary or special orthogonal group and whose base space
s are certain convex polytopes. They are easily defined in terms of matric
es and their truncations\, but do not fit into the familiar framework of i
ntegrable systems with nondegenerate singularities\, and hence are studied
as a sort of edge case.\n\nIt is known that the fibers of these systems a
re determined as iterated pullbacks by the combinatorics of joint eigenval
ues of systems of truncated matrices\, but the resulting expressions can b
e rather inexplicit. We provide a new interpretation of Gelfand–Zeitlin
fibers as balanced products of Lie groups (or biquotients)\, and pursue th
ese viewpoints to a determination of their cohomology rings and low-dimens
ional homotopy groups which can be read transparently off of the combinato
rics.\n\n\nThis all represents joint work with Jeremy Lane.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Naoki Fujita (University of Tokyo)
DTSTART;VALUE=DATE-TIME:20211213T010000Z
DTEND;VALUE=DATE-TIME:20211213T020000Z
DTSTAMP;VALUE=DATE-TIME:20230208T064050Z
UID:CGP_symplectic_seminar/13
DESCRIPTION:Title: Semi-toric degenerations of Richardson varieties from clus
ter algebras\nby Naoki Fujita (University of Tokyo) as part of IBS-CGP
weekly zoom seminar (Fall 2021)\n\nLecture held in Zoom online.\n\nAbstra
ct\nA toric degeneration is a flat degeneration into an irreducible normal
toric variety. In the case of a flag variety\, its toric degeneration wit
h desirable properties induces degenerations of Richardson varieties into
unions of irreducible toric subvarieties\, called semi-toric degenerations
. Semi-toric degenerations are closely related to Schubert calculus. For i
nstance\, Kogan-Miller constructed semi-toric degenerations of Schubert va
rieties from Knutson-Miller's semi-toric degenerations of matrix Schubert
varieties which give a geometric proof of the pipe dream formula of Schube
rt polynomials. In this talk\, we construct a toric degeneration of a flag
variety using its cluster structure\, and see that it induces semi-toric
degenerations of Richardson varieties\, which can be regarded as generaliz
ations of Kogan-Miller's semi-toric degeneration. This talk is partly base
d on a joint work with Hironori Oya.\n
LOCATION:https://researchseminars.org/talk/CGP_symplectic_seminar/13/
END:VEVENT
END:VCALENDAR