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BEGIN:VEVENT
SUMMARY:Gao Chen (University of Wisconsin-Madison)
DTSTART:20200909T200000Z
DTEND:20200909T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/1
DESCRIPTION:Title: The J-equation\, dHYM equation\, and cscK metrics\nby Gao Chen (
University of Wisconsin-Madison) as part of Boston University Geometry/Phy
sics Seminar\n\n\nAbstract\nThe deformed Hermitian-Yang-Mills (dHYM) equat
ion is the mirror equation for the special Lagrangian equation. The "small
radius limit" of the dHYM equation is the J-equation\, which is closely r
elated to the constant scalar curvature K\\"ahler (cscK) metrics. In this
talk\, I will explain my recent result that the solvability of the J-equat
ion is equivalent to a notion of stability. I will also explain my simila
r result on the supercritical dHYM equation as well as the application of
my results to the cscK problem.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Philip Engel (University of Georgia)
DTSTART:20200916T200000Z
DTEND:20200916T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/2
DESCRIPTION:Title: Compactification of K3 moduli\nby Philip Engel (University of Ge
orgia) as part of Boston University Geometry/Physics Seminar\n\n\nAbstract
\nBy the Torelli theorem\, the moduli space of lattice polarized K3 surfac
es is\nthe quotient of a Hermitian symmetric domain by an arithmetic group
. In this capacity\,\nit has compactifications such as the Baily-Borel and
toroidal compactifications\nwhich depend on some choice of fan. On the ot
her hand\, choosing canonically an ample\ndivisor on every such K3\, one c
an build a compactification via so-called (KSBA) stable pairs.\nI will dis
cuss joint work with V. Alexeev on how one proves that the normalization o
f\na stable pair compactification of K3 moduli is the toroidal compactific
ation \nfor an appropriate choice of fan. We will focus on the example of
elliptic K3s\, polarized\nby the section plus the sum of the singular fibe
rs.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Woodward (Rutgers University)
DTSTART:20200923T200000Z
DTEND:20200923T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/3
DESCRIPTION:Title: Fukaya Categories of Blow-ups\nby Chris Woodward (Rutgers Univer
sity) as part of Boston University Geometry/Physics Seminar\n\n\nAbstract\
nThis is joint work with Venugopalan and Xu. \nIn good cases\, we construc
t split-generators for the Fukaya category of sufficiently small symplecti
c blow-ups. For example\, for iterated blow-ups of projective spaces this
implies an affirmative answer to Kontsevich's question on the relation \n
between quantum cohomology and Hochschild cohomology of the Fukaya categor
y.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hang Yuan (Stony Brook University)
DTSTART:20200930T200000Z
DTEND:20200930T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/4
DESCRIPTION:Title: Family Floer theory for toric manifolds\nby Hang Yuan (Stony Bro
ok University) as part of Boston University Geometry/Physics Seminar\n\n\n
Abstract\nGiven a Lagrangian fibration\, my recent work gives a natural co
nstruction of a rigid analytic space and a global Landau-Ginzburg potentia
l\, based on Fukaya’s family Floer theory and non-archimedean geometry.\
n In this talk\, I will discuss my work in progress\, which explains how t
o apply this construction to the toric manifolds. Specifically\, I will di
scuss the moment map fibration on a toric manifold and the Gross’s fibra
tion on a toric Calabi-Yau manifold. I will explain how the outcomes are r
elated to the previous works of Cho-Oh\, Fukaya-Oh-Ohta-Ono\, Chan-Lau-Leu
ng\, and Abouzaid-Auroux-Katzarkov.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Guangbo Xu (Texas A&M University)
DTSTART:20201007T200000Z
DTEND:20201007T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/5
DESCRIPTION:Title: Compactness of instantons and the Atiyah-Floer conjecture\nby Gu
angbo Xu (Texas A&M University) as part of Boston University Geometry/Phys
ics Seminar\n\n\nAbstract\nThe Atiyah-Floer conjecture says that the insta
nton Floer homology of a three-manifold (constructed via gauge theory) agr
ees with a Lagrangian Floer homology (constructed via symplectic geometry)
associated to a splitting of the manifold. Atiyah's heuristic argument of
this conjecture relies on a compactness result for instantons in a certai
n adiabatic limit. I will present a proof of such a compact theorem for th
e case when the gauge group is SO(3)\, as well as another compactness theo
rem related to bounding chains on the symplectic side.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Jordan (University of Edingburgh)
DTSTART:20201014T200000Z
DTEND:20201014T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/6
DESCRIPTION:Title: Cluster quantization of character stacks as a singular topological f
ield theory\nby David Jordan (University of Edingburgh) as part of Bos
ton University Geometry/Physics Seminar\n\n\nAbstract\nCharacter stacks ar
e certain moduli spaces of G-local systems on a manifold\, which arise nat
urally in both 4d N=4 Kapustin-Witten and 3d N=4 Sicilian gauge theories.
Their quantizations relate to deforming the coupling parameter\, and intr
oducing omega-deformation\, respectively. Fock and Goncharov have introdu
ced a modification of character varieties\, in which the G-local systems a
re decorated with parabolic reductions along fixed regions of the surface\
, and on these decorated character varieties they have exhibited cluster s
tructures. This means\, there is a family of open subsets\, indexed combi
natorially\, on which the stack is actually an algebraic torus. The trans
itions between charts are given by certain explicit birational transformat
ions called mutations. Finally\, they have defined a quantization of this
structure\, which has a number of remarkable properties.\n\nIn this talk I
will explain how to upgrade their construction to a fully extended topolo
gical field theory using the framework of stratified factorization homolog
y developed by Ayala-Francis-Tanaka.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tudor Dimofte (University of California\, Davis/ University of Edi
ngurgh)
DTSTART:20201021T200000Z
DTEND:20201021T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/7
DESCRIPTION:Title: 3d A & B models\, mirror symmetry\, and HOMFLY homology\nby Tudo
r Dimofte (University of California\, Davis/ University of Edingurgh) as p
art of Boston University Geometry/Physics Seminar\n\n\nAbstract\nI will re
view some what's known about topological A and B twists of 3d N=4 supersym
metric gauge theories\, in particular the algebraic/categorical structures
that they contain. The physical duality known as 3d mirror symmetry excha
nges 3d A and B twists\, and should manifest mathematically as a higher an
alogue of homological mirror symmetry. I will then explain how these ideas
may be concretely applied to reproduce and connect several different cons
tructions of HOMFLY-PT homology (soon to appear in work with Garner\, Hilb
urn\, Oblomkov\, and Rozansky).\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Pomerleano (University of Massachusetts\, Boston)
DTSTART:20201028T200000Z
DTEND:20201028T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/8
DESCRIPTION:Title: Intrinsic Mirror Symmetry and Categorical Crepant Resolutions\nb
y Daniel Pomerleano (University of Massachusetts\, Boston) as part of Bost
on University Geometry/Physics Seminar\n\n\nAbstract\nA general expectatio
n in mirror symmetry is that the mirror partner to an affine log Calabi-Ya
u variety is "algebraically convex" (meaning it is proper over its affiniz
ation). We will describe work in progress which shows how this algebraic c
onvexity of the mirror manifests itself directly as certain finiteness pro
perties of Floer theoretic invariants of X (the symplectic cohomology and
wrapped Fukaya category). As an application of these finiteness results\,
we will show that for maximally degenerate log Calabi-Yau varieties equipp
ed with a ``homological section\," the wrapped Fukaya of X gives an (intri
nsic) categorical crepant resolution of the affine variety Spec($SH^0(X)$)
.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Laura Fredrickson (University of Oregon)
DTSTART:20201105T210000Z
DTEND:20201105T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/9
DESCRIPTION:Title: The Asymptotic geometry of the Hitchin moduli space\nby Laura Fr
edrickson (University of Oregon) as part of Boston University Geometry/Phy
sics Seminar\n\n\nAbstract\nHitchin's equations are a system of gauge theo
retic equations on a Riemann surface that are of interest in many areas in
cluding representation theory\, Teichm\\"uller theory\, and the geometric
Langlands correspondence. The Hitchin moduli space carries a natural hyper
k\\"ahler metric. An intricate conjectural description of its asymptotic
structure appears in the work of physicists Gaiotto-Moore-Neitzke and ther
e has been a lot of progress on this recently. I will discuss some recent
results using tools coming out of geometric analysis which are well-suite
d for verifying these extremely delicate conjectures. This strategy often
stretches the limits of what can currently be done via\ngeometric analysis
\, and simultaneously leads to new insights into these conjectures.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Angela Gibney (Rutgers University)
DTSTART:20201111T210000Z
DTEND:20201111T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/10
DESCRIPTION:Title: Vertex algebras of CohFT-type\nby Angela Gibney (Rutgers Univer
sity) as part of Boston University Geometry/Physics Seminar\n\n\nAbstract\
nRepresentations of vertex algebras of CohFT-type can be used to construct
vector bundles of coinvariants and conformal blocks on moduli spaces of s
table pointed curves. The name comes from the fact they define semisimple
cohomological field theories. I’ll say something about why one may be in
terested in these bundles and their classes\, and give some examples. This
is about work with Chiara Damiolini and Nicola Tarasca.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jeff Hicks (Cambridge University)
DTSTART:20201118T210000Z
DTEND:20201118T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/11
DESCRIPTION:Title: Lagrangian submanifolds in almost toric fibrations\nby Jeff Hic
ks (Cambridge University) as part of Boston University Geometry/Physics Se
minar\n\n\nAbstract\nMirror symmetry predicts that Lagrangian submanifolds
of a symplectic space X are mirror to coherent sheaves on a ``mirror spac
e'' Y. A proposed mechanism for mirror symmetry comes from almost Lagrangi
an torus fibrations. In this framework\, X and Y are dual Lagrangian torus
fibrations over a common affine base Q. Mirror symmetry arises by degener
ating the symplectic geometry of X and complex geometry of Y to tropical g
eometry on the base Q. We will look at the setting where X is the compleme
nt of the elliptic curve in the projective plane\, and discuss how to cons
truct Lagrangian submanifolds of X from the data of tropical curves in the
base of the fibration.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pierrick Bouseau (CNRS\, Universite Paris Saclay)
DTSTART:20201202T210000Z
DTEND:20201202T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/12
DESCRIPTION:Title: Positivity for the skein algebra of the 4-puncture sphere\nby P
ierrick Bouseau (CNRS\, Universite Paris Saclay) as part of Boston Univers
ity Geometry/Physics Seminar\n\n\nAbstract\nThe skein algebra of a topolog
ical surface is constructed from knots and links in the 3-manifold obtaine
d by taking the product of the surface with an interval. A conjecture of D
ylan Thurston predicts the positivity of the structure constants of a cert
ain linear basis of the skein algebra. I will explain a recent proof of th
is conjecture for the skein algebra of the 4-punctured sphere. In a slight
ly surprising way\, this proof of a topological result relies on complex a
lgebraic geometry\, and in particular the study of algebraic curves in com
plex cubic surfaces.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hulya Arguz (University of Versailles - Paris Saclay)
DTSTART:20201209T210000Z
DTEND:20201209T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/13
DESCRIPTION:Title: Computing punctured log Gromov--Witten invariants via wall-crossing
\nby Hulya Arguz (University of Versailles - Paris Saclay) as part of
Boston University Geometry/Physics Seminar\n\nAbstract: TBA\n\nComputing p
unctured log Gromov--Witten invariants via wall-crossing \nAbstract: Punct
ured log Gromov—Witten invariants of Abramovich—Chen--Gross—Siebert
are obtained by counting stable maps with prescribed tangency conditions (
which are allowed to be negative) relative to a not necessarily smooth div
isor. We provide a technique based on tropical geometry and wall-crossing
algorithms to compute punctured log Gromov-Witten invariants of log Calabi
-Yau varieties which are obtained by blowing-up of toric varieties along h
ypersurfaces on the toric boundary. This is joint work with Mark Gross (ar
xiv:2007.08347).\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Valentino Tosatti (McGill University)
DTSTART:20210127T210000Z
DTEND:20210127T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/14
DESCRIPTION:Title: Smooth asymptotics for collapsing Ricci-flat metrics\nby Valent
ino Tosatti (McGill University) as part of Boston University Geometry/Phys
ics Seminar\n\nLecture held in Zoom meeting ID: 974 5641 9902.\n\nAbstract
\nI will discuss the problem of understanding the collapsing behavior of R
icci-flat Kahler metrics on a Calabi-Yau manifold that admits a holomorphi
c fibration structure\, when the Kahler class degenerates to the pullback
of a Kahler class from the base. I will present new work with Hans-Joachim
Hein where we obtain a priori estimates of all orders for the Ricci-flat
metrics away from the singular fibers\, as a corollary of a complete asymp
totic expansion.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sam Payne (University of Texas\, Austin)
DTSTART:20210210T210000Z
DTEND:20210210T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/15
DESCRIPTION:Title: Top weight cohomology of M_g\nby Sam Payne (University of Texas
\, Austin) as part of Boston University Geometry/Physics Seminar\n\nLectur
e held in Zoom meeting ID: 974 5641 9902.\n\nAbstract\nI will discuss an a
pproach to studying the top-graded piece of the weight filtration on open
moduli spaces with suitable toroidal compactifications\, inspired by tropi
cal and non-archimedean analytic geometry. One application of this approa
ch is the recent proof\, joint with Chan and Galatius\, that the dimension
of H^{4g-6}(M_g\, Q) grows exponentially with g. This growth was unexpect
ed and disproves conjectures of Church-Farb-Putman and Kontsevich.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tony Yue Yu (Université Paris-Sud\, Paris-Saclay)
DTSTART:20210217T190000Z
DTEND:20210217T200000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/16
DESCRIPTION:Title: Frobenius structure conjecture and application to cluster algebras<
/a>\nby Tony Yue Yu (Université Paris-Sud\, Paris-Saclay) as part of Bost
on University Geometry/Physics Seminar\n\nLecture held in Zoom meeting ID:
974 5641 9902.\n\nAbstract\nI will explain the Frobenius structure conjec
ture of Gross-Hacking-Keel in mirror symmetry\, and an application towards
cluster algebras. Let U be an affine log Calabi-Yau variety containing an
open algebraic torus. We show that the naive counts of rational curves in
U uniquely determine a commutative associative algebra equipped with a co
mpatible multilinear form. Although the statement of the theorem involves
only elementary algebraic geometry\, the proof employs Berkovich non-archi
medean analytic methods. We construct the structure constants of the algeb
ra via counting non-archimedean analytic disks in the analytification of U
. I will explain various properties of the counting\, notably deformation
invariance\, symmetry\, gluing formula and convexity. In the special case
when U is a Fock-Goncharov skew-symmetric X-cluster variety\, our algebra
generalizes\, and gives a direct geometric construction of\, the mirror al
gebra of Gross-Hacking-Keel-Kontsevich. The comparison is proved via a can
onical scattering diagram defined by counting infinitesimal non-archimedea
n analytic cylinders\, without using the Kontsevich-Soibelman algorithm. S
everal combinatorial conjectures of GHKK\, as well as the positivity in th
e Laurent phenomenon\, follow readily from the geometric description. This
is joint work with S. Keel\, arXiv:1908.09861. If time permits\, I will m
ention another application towards the moduli space of KSBA (Kollár-Sheph
erd-Barron-Alexeev) stable pairs\, joint with P. Hacking and S. Keel\, arX
iv: 2008.02299.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hariharan Narayanan (Tata Institute for Fundamental Research)
DTSTART:20210224T160000Z
DTEND:20210224T170000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/17
DESCRIPTION:Title: Testing the manifold hypothesis and fitting a manifold of large rea
ch to noisy data\nby Hariharan Narayanan (Tata Institute for Fundament
al Research) as part of Boston University Geometry/Physics Seminar\n\nLect
ure held in Zoom meeting ID: 974 5641 9902.\n\nAbstract\nThe hypothesis th
at high dimensional data tend to lie in the vicinity of a low dimensional
manifold is the basis of manifold learning. \nWe will discuss a joint work
with Charles Fefferman and Sanjoy Mitter on testing the manifold hypothes
is. We will outline an algorithm (with accompanying complexity guarantees)
for fitting a manifold to an unknown probability distribution supported i
n a separable Hilbert space\, only using i.i.d samples from that distribut
ion.\nWe also give a solution based on joint work with Charles Fefferman\,
Sergei Ivanov and Matti Lassas to the following question from manifold le
arning.\nSuppose data belonging to a high dimensional Euclidean space is s
ampled independently\, identically at random\, from a measure supported on
a d dimensional twice differentiable embedded manifold M\, and corrupted
by Gaussian noise with small standard deviation sigma. How can we produce
a manifold M_o whose Hausdorff distance to M is small and whose reach (nor
mal injectivity radius) is not much smaller than the reach of M? We show h
ow to produce a manifold within O(sigma^2) of M in Hausdorf distance\, who
se reach is smaller than that of M by a factor of no more than O(d^6).\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Suvrit Sra (MIT)
DTSTART:20210303T204500Z
DTEND:20210303T214500Z
DTSTAMP:20260404T110827Z
UID:BUGeom/18
DESCRIPTION:Title: Accelerated gradient methods on Riemannian manifolds\nby Suvrit
Sra (MIT) as part of Boston University Geometry/Physics Seminar\n\nLectur
e held in Zoom meeting ID: 974 5641 9902.\n\nAbstract\nThis talk lies at t
he interface of geometry and optimization. I'll talk about geodesically co
nvex optimization problems\, a rich class of non-convex optimization probl
ems that admit tractable global optimization. I'll provide some background
on this class and some motivating examples. Beyond a general introduction
to the topic area\, I will dive deeper into a recent discovery of a long-
sought result: an accelerated gradient method for Riemannian manifolds. To
wards developing this method\, we will revisit Nesterov's (Euclidean) esti
mate sequence technique and present a conceptually simple alternative. We
will then generalize this simpler alternative to the Riemannian setting. C
ombined with a new geometric inequality\, we will then obtain the first (g
lobal) accelerated Riemannian-gradient method. I'll also comment on some v
ery recent updates on this topic.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Olivier Schiffmann (Université de Paris-Sud ORSAY)
DTSTART:20210317T200000Z
DTEND:20210317T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/19
DESCRIPTION:Title: Cohomological Hall algebras\, Yangians and Kleinian surface singula
rities\nby Olivier Schiffmann (Université de Paris-Sud ORSAY) as part
of Boston University Geometry/Physics Seminar\n\nLecture held in Zoom mee
ting ID: 974 5641 9902.\n\nAbstract\nModuli spaces of sheaves on complex s
urfaces play an important role in algebraic geometry\, with motivation com
ing from (among others) string theory and gauge theory.\n\nOne way to unde
rstand the structure of the cohomology of such moduli spaces is to constru
ct an action of a suitable algebra\, through some 'Hecke type' corresponde
nces. Traditionally\, one considers Hecke correspondences modifying a shea
f at a single point (varying along a fixed cycle on the surface). In an on
going joint work with Diaconescu\, Sala and Vasserot\, we consider the cas
e of resolutions of Kleinian singularities\, and modifications along the (
1-dimensional) components of the exceptional locus. This yields actions of
some Yangian type algebras (more precisely\, affine Yangians). The main t
ool is the notion of cohomological Hall algebra\, and the main technical r
esult describes the behavior of such algebras upon derived equivalences co
ming from reflection functors.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andy Neitzke (Yale University)
DTSTART:20210331T200000Z
DTEND:20210331T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/20
DESCRIPTION:Title: An update on hyperkahler metrics on moduli of Higgs bundles\nby
Andy Neitzke (Yale University) as part of Boston University Geometry/Phys
ics Seminar\n\nLecture held in Zoom meeting ID: 974 5641 9902.\n\nAbstract
\nIn joint work with Davide Gaiotto and Greg Moore\, we gave a\nconjectura
l construction of the hyperkahler metric on moduli spaces of Higgs\nbundle
s. The key new ingredients in this construction are counts of BPS states\n
(Donaldson-Thomas-type invariants).\n\nThrough the work of various authors
\, including me\, Dumas\, Fredrickson\,\nMazzeo\, Swoboda\, Weiss\, Witt\,
there is now some evidence that this\nconjectural picture is correct. On
the one hand\, some of the asymptotic\npredictions which follow from the c
onjecture have been proven\; on the other\nhand\, there is numerical evide
nce that the conjecture is correct even far\naway from the asymptotic limi
t. I will review these developments.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Travis Mandel (University of Oklahoma)
DTSTART:20210310T210000Z
DTEND:20210310T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/21
DESCRIPTION:Title: Tropical multiplicities from polyvector fields and QFT\nby Trav
is Mandel (University of Oklahoma) as part of Boston University Geometry/P
hysics Seminar\n\nLecture held in Zoom meeting ID: 974 5641 9902.\n\nAbstr
act\nWhen considering planar tropical curves satisfying point conditions\,
Mikhalkin expressed the tropical curves' multiplicities as the product of
the multiplicities of their vertices. Such a decomposition of the multip
licity into local computations is very useful in practice\, e.g.\, in the
Gross-Siebert program. I will describe joint work with H. Ruddat in which
we give such localized tropical multiplicity formulas very generally (in
genus 0) using mirror polyvector fields. Our approach involves developing
a notion of tropical quantum field theory which works for all genera.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cheuk Yu Mak (University of Edinburgh)
DTSTART:20210203T210000Z
DTEND:20210203T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/22
DESCRIPTION:Title: Non-displaceable Lagrangian links in four-manifolds\nby Cheuk Y
u Mak (University of Edinburgh) as part of Boston University Geometry/Phys
ics Seminar\n\nLecture held in Zoom meeting ID: 974 5641 9902.\n\nAbstract
\nOne of the earliest fundamental applications of Lagrangian Floer theory
is detecting the non-displaceablity of a Lagrangian submanifold. Many pro
gress and generalisations have been made since then but little is known wh
en the Lagrangian submanifold is disconnected. In this talk\, we describe
a new idea to address this problem. Subsequently\, we explain how to use
Fukaya-Oh-Ohta-Ono and Cho-Poddar theory to show that for every S^2 \\tim
es S^2 with a non-monotone product symplectic form\, there is a continuum
of disconnected\, non-displaceable Lagrangian submanifolds such that each
connected component is displaceable. This is a joint work with Ivan Smith
.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Umut Varolgunes (Stanford University)
DTSTART:20210324T200000Z
DTEND:20210324T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/23
DESCRIPTION:Title: Computations in relative symplectic cohomology\nby Umut Varolgu
nes (Stanford University) as part of Boston University Geometry/Physics Se
minar\n\nLecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nThis
is joint work with Yoel Groman. I will present some computations of relat
ive symplectic cohomology for pre-images of compact subsets in bases of ce
rtain Lagrangian torus fibrations. I will then explain how these computati
ons lead to constructions of non-archimedean mirrors with expected propert
ies. In particular\, I will explain the relevance of the locality theorem
that we are currently finishing writing up and the Mayer-Vietoris property
that I had proven in my thesis.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marco Gualtieri (University of Toronto)
DTSTART:20210505T200000Z
DTEND:20210505T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/24
DESCRIPTION:by Marco Gualtieri (University of Toronto) as part of Boston U
niversity Geometry/Physics Seminar\n\nLecture held in Zoom meeting ID: 953
4652 9200.\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pavel Safronov (University of Edinburgh)
DTSTART:20210407T200000Z
DTEND:20210407T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/25
DESCRIPTION:Title: Kapustin—Witten TQFT on 3-manifolds and derived skein modules
\nby Pavel Safronov (University of Edinburgh) as part of Boston University
Geometry/Physics Seminar\n\nLecture held in Zoom meeting ID: 953 4652 920
0.\n\nAbstract\nKapustin and Witten have proposed that there is a 4-dimens
ional TQFT underlying the geometric Langlands program and have described i
t as a topological twist of the 4-dimensional maximally supersymmetric Yan
g—Mills theory. In this talk I will discuss some mathematically-rigorous
ways to define the space of states for 3-manifolds\, relating it to skein
modules and complexified instanton Floer homology of Abouzaid—Manolescu
. I will also comment on the possible extension of the geometric Langlands
duality to 3-manifolds. This is based on work in progress with D. Jordan
and S. Gunningham.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Oleg Lazarev (Columbia University)
DTSTART:20210414T200000Z
DTEND:20210414T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/26
DESCRIPTION:Title: Inverting primes in symplectic geometry\nby Oleg Lazarev (Colum
bia University) as part of Boston University Geometry/Physics Seminar\n\nL
ecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nA classical co
nstruction in topology associates to a space X and prime p\, a new "locali
zed" space X_p whose homotopy and homology groups are obtained from those
of X by inverting p. In this talk\, I will discuss a symplectic analog of
this construction and explain how it interpolates between "flexible" and "
rigid" symplectic manifolds. \n\nConcretely\, I will produce prime-localiz
ed Weinstein subdomains of high-dimensional Weinstein domains (which can
be thought of as singular Lagrangians) and show that any Weinstein subdoma
in of a cotangent bundle agrees Fukaya-categorically with one of these spe
cial subdomains. The key will be to classify which objects of the Fukaya c
ategory of T*M - twisted complexes of Lagrangians - are quasi-isomorphic t
o actual Lagrangians. This talk is based on joint work with Zach Sylvan an
d Hiro Lee Tanaka.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marco Armenta (Université de Sherbrooke\, Sherbrooke)
DTSTART:20210421T200000Z
DTEND:20210421T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/27
DESCRIPTION:Title: Derived invariance of operations in Hochschild theory\nby Marco
Armenta (Université de Sherbrooke\, Sherbrooke) as part of Boston Univer
sity Geometry/Physics Seminar\n\nLecture held in Zoom meeting ID: 953 4652
9200.\n\nAbstract\nIn this talk\, I will introduce Hochschild homology an
d cohomology\, together with the well-known operations cup product and Ger
stenhaber bracket\, and the not-so-known cap product and Connes differenti
al. I will explain how all these operations can be interpreted inside the
derived category of the algebra which allows proving derived invariance of
the whole structure\, known as a Tamarkin-Tsygan calculus or a differenti
al calculus. Finally\, I will show how this construction is functorial in
the algebra using cyclic homology\, and give an example showing that the T
amarkin-Tsygan calculus is not a complete derived invariant\, by means of
quivers and the Coxeter polynomial. This is joint work with Bernhard Kelle
r.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marco Gualtieri (University of Toronto)
DTSTART:20210428T200000Z
DTEND:20210428T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/28
DESCRIPTION:Title: Branes\, Groupoids\, and Quantization\nby Marco Gualtieri (Univ
ersity of Toronto) as part of Boston University Geometry/Physics Seminar\n
\nLecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nIn the past
few years\, new light has been shed on the notion of\ngeneralized Kahler
geometry\, by using ideas from the Weinstein school\nof Poisson geometry.
We now understand that the generalized Kahler\nmetric may be viewed as an
imaginary Lagrangian submanifold in a\nholomorphic symplectic groupoid whi
ch encodes the pair of holomorphic\nPoisson structures underlying the gene
ralized Kahler structure.\nAfter explaining how this mechanism works\, I w
ill show how it leads to\na method for quantizing certain holomorphic Pois
son structures in a\nfashion similar to that used in the work of Gukov and
Witten on\ngeometric quantization. This is an ongoing joint work with Fr
ancis\nBischoff.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Miranda Cheng (Academia Sinica/University of Amsterdam)
DTSTART:20210915T150000Z
DTEND:20210915T160000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/29
DESCRIPTION:Title: Three-Manifolds\, Quantum Modular Forms and log VOAs\nby Mirand
a Cheng (Academia Sinica/University of Amsterdam) as part of Boston Univer
sity Geometry/Physics Seminar\n\nLecture held in Zoom meeting ID: 937 3195
9866.\n\nAbstract\nQuantum modular forms are\, roughly speaking\, functio
ns that have certain weak modular properties. Mock modular forms and false
theta functions are examples of holomorphic functions on the upper-half p
lane which lead to quantum modular forms. Generalising the Witten-Reshetik
hin-Turaev invariants for three-manifolds which arise from Chern-Simons th
eory\, a new topological invariant named homological blocks which arise fr
om 6d SCFT have been proposed a few years ago. My talk aims to explain the
recent observations on the quantum modular properties of the homological
blocks\, as well as the relation to logarithmic vertex algebras. The talk
will be based on a series of work in collaboration with Sungbong Chun\, Io
ana Coman Lohi\, Boris Feigin\, Francesca Ferrari\, Sergei Gukov\, Sarah H
arrison\, Davide Passaro\, and Gabriele Sgroi.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stephan Stolz (University of Notre Dame)
DTSTART:20211027T200000Z
DTEND:20211027T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/31
DESCRIPTION:Title: TMF-cohomology via 2-dimensional QFTs\nby Stephan Stolz (Univer
sity of Notre Dame) as part of Boston University Geometry/Physics Seminar\
n\nLecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nTopologica
l modular form theory is a generalized cohomology theory whose coefficient
ring TMF^*(point) is rationally isomorphic to the ring of integral modula
r forms. Modular forms also show up as partition functions of suitable 2-d
imensional QFTs. For example\, the Witten genus W(X) of a closed manifold
X is an integral modular form\, provided X is a spin manifold and the firs
t Pontryagin class of X is trivial. This led to the question whether the c
orresponding spectrum TMF can be constructed in terms of 2D field theories
. \n\n\nIn this talk I will recall a result of Teichner and myself accord
ing to which the partition function of a supersymmetric 2D Euclidean field
theory is an integral modular form\, as well as a Conjecture expressing t
he spaces which form the spectrum TMF as spaces of supersymmetric 2D field
theories.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Charles Doran (University of Alberta)
DTSTART:20211110T210000Z
DTEND:20211110T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/32
DESCRIPTION:Title: The Greene-Plesser Construction Revisited\nby Charles Doran (Un
iversity of Alberta) as part of Boston University Geometry/Physics Seminar
\n\nLecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nThe first
known construction of mirror pairs of Calabi-Yau manifolds was the Greene
-Plesser “quotient and resolve” procedure which applies to pencils of
hypersurfaces in projective space. We’ll review this approach\, uncover
the hints it gives for some more general mirror constructions\, and descr
ibe a brand-new variant that applies to pencils of hypersurfaces in Grassm
annians. This last is joint work with Tom Coates and Elana Kalashnikov (a
rXiv:2110.0727).\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Emily Cliff (University of Sherbrooke)
DTSTART:20211201T210000Z
DTEND:20211201T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/33
DESCRIPTION:Title: Moduli spaces of principal 2-group bundles and a categorification o
f the Freed--Quinn line bundle\nby Emily Cliff (University of Sherbroo
ke) as part of Boston University Geometry/Physics Seminar\n\nLecture held
in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nA 2-group is a higher cate
gorical analogue of a group\, while a smooth 2-group is a higher categoric
al analogue of a Lie group. An important example is the string 2-group\, d
efined by Schommer-Pries. We study the notion of principal bundles for smo
oth 2-groups\, and investigate the moduli "space" of such objects. \n\n\n\
nIn particular in the case of flat principal bundles for a finite 2-group
over a Riemann surface\, we prove that the moduli space gives a categorifi
cation of the Freed--Quinn line bundle. This line bundle has as its global
sections the state space of Chern--Simons theory for the underlying finit
e group. We can also use our results to better understand the notion of ge
ometric string structures (as previously studied by Waldorf and Stolz--Tei
chner).\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhengping Gui (ITCP)
DTSTART:20220209T210000Z
DTEND:20220209T220000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/34
DESCRIPTION:Title: Elliptic trace map on chiral algebras\nby Zhengping Gui (ITCP)
as part of Boston University Geometry/Physics Seminar\n\nLecture held in Z
oom meeting ID: 953 4652 9200.\n\nAbstract\nTrace map on deformation quant
ized algebra leads to the\nalgebraic index theorem. We investigate a two d
imensional chiral analogue\nof the algebraic index theorem via the theory
of chiral algebras developed\nby Beilinson and Drinfeld. We construct a tr
ace map on the elliptic chiral\nhomology of the free beta-gamma system usi
ng the BV\nquantization framework. As an example\, we compute the trace ev
aluated on\nthe unit constant chiral chain and obtain the formal Witten ge
nus in the\nLie algebra cohomology.\nThis talk is based on joint work with
Si Li.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kevin Costello (Perimeter Institute)
DTSTART:20220330T200000Z
DTEND:20220330T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/35
DESCRIPTION:Title: Amplitudes as vertex algebra correlators\nby Kevin Costello (Pe
rimeter Institute) as part of Boston University Geometry/Physics Seminar\n
\nLecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nI will talk
about joint work with Natalie Paquette\, which demonstrates how certain s
cattering amplitudes of a 4 dimensional gauge theory can be computed as co
rrelation functions of a vertex algebra. This will be aimed at a mathemat
ical audience\, and I will attempt to define any unfamiliar concepts.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrew Linshaw (University of Denver)
DTSTART:20220413T200000Z
DTEND:20220413T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/36
DESCRIPTION:Title: Global sections of the chiral de Rham complex for Calabi-Yau and hy
perkahler manifolds\nby Andrew Linshaw (University of Denver) as part
of Boston University Geometry/Physics Seminar\n\nLecture held in Zoom meet
ing ID: 953 4652 9200.\n\nAbstract\nFor any complex manifold M\, the chira
l de Rham complex is a sheaf of vertex algebras on M that was introduced i
n 1998 by Malikov\, Schechtman\, and Vaintrob. It is N-graded by conformal
weight\, and the weight zero piece coincides with the ordinary de Rham sh
eaf. When M is a Calabi-Yau manifold with holonomy group SU(d)\, it was sh
own by Ekstrand\, Heluani\, Kallen and Zabzine that the algebra of global
sections \\Omega^{ch}(M) contains a certain vertex algebra defined by Odak
e which is an extension of the N=2 superconformal algebra. When M is a hyp
erkahler manifold\, it was shown by Ben-Zvi\, Heluani\, and Szczesny that
\\Omega^{ch}(M) contains the small N=4 superconformal algebra. In this tal
k\, we will show that in both cases\, these subalgebras are actually the f
ull algebras of global sections. In an earlier work\, Bailin Song has show
n that the global section algebra can be identified with a certain subalge
bra of a free field algebra which is invariant under the action of an infi
nite-dimensional Lie algebra of Cartan type. The key observation is that t
his algebra can be described using the arc space analogue of Weyl's first
and second fundamental theorems of invariant theory for the special linear
and symplectic groups. \n\n \n\nThis is a joint work with Bailin Song.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nate Bottman (Max-Planck Institute)
DTSTART:20220504T200000Z
DTEND:20220504T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/37
DESCRIPTION:Title: The Barr--Beck theorem in symplectic geometry\nby Nate Bottman
(Max-Planck Institute) as part of Boston University Geometry/Physics Semin
ar\n\nLecture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nThe Bar
r--Beck theorem gives conditions under which an adjunction F -| G is monad
ic. Monadicity\, in turn\, means that the category on the right can be com
puted in terms of the data of the category on the left and its endomorphis
m GF. I will present joint work-in-progress with Abouzaid\, in which we co
nsider this theorem in the case of the functors between Fuk(M1) and Fuk(M2
) associated to a Lagrangian correspondence L12 and its transpose. These f
unctors are often adjoint\, and under the hypothesis that a certain map to
symplectic cohomology hits the unit\, the hypotheses of Barr--Beck are sa
tisfied. This can be interpreted as an extension of Abouzaid's generation
criterion\, and we hope that it will be a useful tool in the computation o
f Fukaya categories.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/37/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gurbir Dhillon (Yale University)
DTSTART:20220914T200000Z
DTEND:20220914T210000Z
DTSTAMP:20260404T110827Z
UID:BUGeom/38
DESCRIPTION:Title: The log Kazhdan--Lusztig correspondence\nby Gurbir Dhillon (Yal
e University) as part of Boston University Geometry/Physics Seminar\n\nLec
ture held in Zoom meeting ID: 953 4652 9200.\n\nAbstract\nA landmark disco
very of the 1980s\, due to many mathematicians and\nphysicists (Drinfeld\,
Kohno\, Witten\, etc.)\, was the close relationship between quantum group
s and affine Lie algebras. Kazhdan–Lusztig established a sharp form of\n
this in representation theory via an equivalence of braided tensor categor
ies of modules. The subtlest cases of their result occur when the quantum
parameter q is\na root of unity\, where one has to pick the right form of
the quantum group (the\nso-called Lusztig\, or divided-powers form) in ord
er for the equivalence to hold. In\nthe mid-2000s\, Feigin–Gainutdinov
–Semikhatov–Tipunin conjectured a similar ‘log\nKazhdan–Lusztig co
rrespondence’ between representations of another version of the\nquantum
group\, the small quantum group\, and a vertex algebra known as the tripl
et\,\nat certain roots of unity. After providing a survey of these influen
tial works for nonspecialists\, we will propose a conjecture extending tha
t of Feigin et. al. to all roots\nof unity. Time permitting\, we will indi
cate a way to prove it conditional on some\nfoundational conjectures in qu
antum geometric Langlands.\n
LOCATION:https://stable.researchseminars.org/talk/BUGeom/38/
END:VEVENT
END:VCALENDAR