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BEGIN:VEVENT
SUMMARY:Duncan McCoy (UQAM)
DTSTART:20200914T190000Z
DTEND:20200914T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/1
DESCRIPTION:Title: Double slicing for links\nby Duncan McCoy (UQAM) as part of MIT G
eometry and Topology Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mark Powell
DTSTART:20200928T190000Z
DTEND:20200928T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/2
DESCRIPTION:Title: Stable diffeomorphism of 4-manifolds\nby Mark Powell as part of M
IT Geometry and Topology Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ian Zemke
DTSTART:20201005T190000Z
DTEND:20201005T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/3
DESCRIPTION:Title: A few refinements of Heegaard Floer genus and clasp number bounds
\nby Ian Zemke as part of MIT Geometry and Topology Seminar\n\nAbstract: T
BA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Patrick Orson
DTSTART:20201019T190000Z
DTEND:20201019T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/5
DESCRIPTION:Title: Topologically embedding spheres in knot traces\nby Patrick Orson
as part of MIT Geometry and Topology Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shaoyun Bai
DTSTART:20201109T200000Z
DTEND:20201109T210000Z
DTSTAMP:20260404T094556Z
UID:mitgt/6
DESCRIPTION:Title: Equivariant Cerf theory and SU(n) Casson invariants\nby Shaoyun B
ai as part of MIT Geometry and Topology Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aliakbar Daemi
DTSTART:20201116T200000Z
DTEND:20201116T210000Z
DTSTAMP:20260404T094556Z
UID:mitgt/7
DESCRIPTION:Title: Chern-Simons functional\, singular instantons\, and the four-dimensio
nal clasp number\nby Aliakbar Daemi as part of MIT Geometry and Topolo
gy Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kouki Sato
DTSTART:20201130T150000Z
DTEND:20201130T160000Z
DTSTAMP:20260404T094556Z
UID:mitgt/8
DESCRIPTION:Title: Filtered instanton Floer homology and the homology cobordism group\nby Kouki Sato as part of MIT Geometry and Topology Seminar\n\n\nAbstrac
t\nNote the time change!\n\nWe introduce a family of real-valued homology
cobordism invariants r_s(Y) of oriented homology 3-spheres. The invariants
r_s(Y) are based on a quantitative construction of filtered instanton Flo
er homology. Using our invariants\, we give several new constraints of the
set of smooth boundings of homology 3-spheres. As one of the corollaries\
, we give infinitely many homology 3-spheres which cannot bound any defini
te 4-manifold. As another corollary\, we show that if the 1-surgery of a k
not has negative Froyshov invariant\, then the 1/n-surgeries (n>0) of the
knot are linearly independent in the homology cobordism group. This is a j
oint work with Yuta Nozaki and Masaki Taniguchi.\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Markus Land
DTSTART:20210222T200000Z
DTEND:20210222T210000Z
DTSTAMP:20260404T094556Z
UID:mitgt/9
DESCRIPTION:Title: Cobordism categories\, hermitian K-theory\, and (stable) cohomology o
f automorphism groups\nby Markus Land as part of MIT Geometry and Topo
logy Seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arun Debray
DTSTART:20210301T200000Z
DTEND:20210301T210000Z
DTSTAMP:20260404T094556Z
UID:mitgt/10
DESCRIPTION:Title: Stable diffeomorphism classification of some unorientable 4-manifold
s\nby Arun Debray as part of MIT Geometry and Topology Seminar\n\n\nAb
stract\nKreck's modified surgery theory provides a bordism-theoretic class
ification of closed\, connected 4-manifolds up to stable diffeomorphism\,
i.e. up to diffeomorphism after connect-sum with some number of copies of
S^2 x S^2. For some classes of unorientable 4-manifolds with fundamental g
roup pi_1 finite of order 2 mod 4\, the classification question simplifies
considerably\, reducing to the case where pi_1 = Z/2. In this talk\, I'll
explain the generalities of Kreck's theorem and the ingredients that go i
nto it\, then specialize and give the classification in the case where pi_
1 is finite of order 2 mod 4. If time remains\, I'll discuss what changes
when one asks about the stable homeomorphism classification of topological
4-manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Danica Kosanovic
DTSTART:20210315T190000Z
DTEND:20210315T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/11
DESCRIPTION:Title: Knotted families of arcs\nby Danica Kosanovic as part of MIT Geo
metry and Topology Seminar\n\n\nAbstract\nGoodwillie and Weiss developed a
powerful homotopy theoretic technique for studying spaces of embeddings.
For properly embedded arcs in a manifold of any dimension these techniques
can be given a geometric flavour inspired by Vassiliev theory for classic
al knots. The outcome is a set of explicit nontrivial classes in homotopy
groups of spaces of arcs. I will give an overview of this story\, and also
outline how such computations can be applied to some open problems in 4-d
imensional topology. The latter is joint work with Peter Teichner.\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Slava Krushkal
DTSTART:20210329T190000Z
DTEND:20210329T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/13
DESCRIPTION:Title: Filling links in 3-manifolds\nby Slava Krushkal as part of MIT G
eometry and Topology Seminar\n\nAbstract: TBA\n\nI will discuss the notion
of filling links in 3-manifolds: a link is filling if any 1-spine of the
3-manifold\, disjoint from the link\, injects into the link complement on
the level of the fundamental group. I will give a construction of links in
the 3-torus which are filling modulo terms of the lower central series\;
the proof relies on a new extension of the Stallings theorem. I will also
discuss the construction of Leininger and Reid of filling links and spines
in 3-manifolds of rank 2\, and formulate some open problems. (Joint work
with Michael Freedman)\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Baldwin
DTSTART:20210405T190000Z
DTEND:20210405T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/14
DESCRIPTION:Title: Instanton L-spaces and splicing\nby John Baldwin as part of MIT
Geometry and Topology Seminar\n\n\nAbstract\nWe prove that the 3-manifold
obtained by gluing the complements of two nontrivial knots in homology 3-s
phere instanton L-spaces\, by a map which identifies meridians with Seifer
t longitudes\, cannot be an instanton L-space. This recovers the recent th
eorem of Lidman-Pinzon-Caicedo-Zentner that the fundamental group of every
closed\, oriented\, toroidal 3-manifold admits a nontrivial SU(2)-represe
ntation\, and consequently Zentner's earlier result that the fundamental g
roup of every closed\, oriented 3-manifold besides the 3-sphere admits a n
ontrivial SL(2\, C)-representation. This is joint work with Steven Sivek.\
n
LOCATION:https://stable.researchseminars.org/talk/mitgt/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anubhav Mukherjee
DTSTART:20210412T190000Z
DTEND:20210412T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/15
DESCRIPTION:Title: Obstructions to embeddings in 4-manifolds using Bauer--Furuta type i
nvariant\nby Anubhav Mukherjee as part of MIT Geometry and Topology Se
minar\n\n\nAbstract\nIn this talk I will discuss some new properties of an
invariant for 4-manifold with boundary which was originally defined by No
buo Iida. As one of the applications of this new invariant I will demonstr
ate how one can obstruct a knot from being h-slice (i.e bound a homologica
lly trivial disk) in 4-manifolds. Also\, this invariant can be useful to d
etect exotic smooth structures of 4-manifolds. This a joint work with Nobu
o Iida and Masaki Taniguchi.\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Kindred
DTSTART:20210426T190000Z
DTEND:20210426T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/16
DESCRIPTION:Title: Replumbing definite surfaces: the geometric content of the flyping t
heorem\nby Thomas Kindred as part of MIT Geometry and Topology Seminar
\n\n\nAbstract\nIn 1898\, P.G. Tait asserted several properties of alterna
ting link diagrams\, which remained unproven until the discovery of the Jo
nes polynomial in 1985. By 1993\, the Jones polynomial had led to proofs o
f all of Tait's conjectures\, but the geometric content of these new resul
ts remained mysterious.\n\nIn 2017\, Howie and Greene independently gave t
he first geometric characterizations of alternating links\; as a corollary
\, Greene obtained the first purely geometric proof of part of Tait's conj
ectures. Recently\, I used these characterizations and "replumbing" moves\
, among other techniques\, to give the first entirely geometric proof of T
ait's flyping conjecture\, first proven in 1993 by Menasco and Thistlethwa
ite.\n\nI will describe these recent developments\, focusing in particular
on the fundamentals of plumbing (also called Murasugi sum) and definite s
urfaces (which characterize alternating links a la Greene). As an aside\,
I will use these two techniques to give a simple proof of the classical re
sult of Murasugi and Crowell that the genus of an alternating knot equals
half the degree of its Alexander polynomial. The talk will be broadly acce
ssible. Expect lots of pictures!\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dave Gabai
DTSTART:20210503T190000Z
DTEND:20210503T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/17
DESCRIPTION:Title: Knotted 3-balls in the 4-sphere\nby Dave Gabai as part of MIT Ge
ometry and Topology Seminar\n\n\nAbstract\nWe give examples of codimension
-1 knotting in the 4-sphere\, i.e. there are 3-balls B_1 with boundary the
standard 2-sphere\, which are not isotopic rel boundary to the standard 3
-ball B_0. In fact isotopy classes of such balls form a group which is inf
initely generated. The existence of knotted balls implies that there exist
s inequivalent fiberings of the unknot in the 4-sphere\, in contrast to th
e situation in dimension-3. Also\, that there exists diffeomorphisms of S^
1 x B^3 homotopic rel boundary to the identity\, but not isotopic rel boun
dary to the identity. (Joint work with Ryan Budney)\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:William Olsen
DTSTART:20210510T190000Z
DTEND:20210510T200000Z
DTSTAMP:20260404T094556Z
UID:mitgt/18
DESCRIPTION:Title: Trisections and Ozsvath-Szabo cobordism maps\nby William Olsen a
s part of MIT Geometry and Topology Seminar\n\n\nAbstract\nGiven a smooth\
, oriented four-manifold X with connected boundary\, we'll demonstrate how
to use the data of a trisection (in particular\, its diagrammatic and fib
ration structures) to compute the induced cobordism maps in Heegaard Floer
homology.\n
LOCATION:https://stable.researchseminars.org/talk/mitgt/18/
END:VEVENT
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