BEGIN:VCALENDAR
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PRODID:researchseminars.org
CALSCALE:GREGORIAN
X-WR-CALNAME:researchseminars.org
BEGIN:VEVENT
SUMMARY:Peter Kronheimer (Harvard)
DTSTART:20200505T140000Z
DTEND:20200505T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/1
DESCRIPTION:Title: Genus versus double-points for immersed surfaces\nby Peter Kronhe
imer (Harvard) as part of Regensburg low-dimensional geometry and topology
seminar\n\n\nAbstract\nIf X is a simply-connected closed 4-manifold conta
ining an oriented embedded surface S of genus g\, is there always an immer
sed sphere S' which represents the same homology class and has only g tran
sverse double-points? Colloquially\, can we "trade handles for double poin
ts"? This is an open question\, though a "relative" version of the questio
n (concerning surfaces in the 4-ball bounding a given knot in the 3-sphere
) is known to have a negative answer. For closed surfaces in closed 4-mani
folds\, a particularly interesting class of examples comes from algebraic
geometry\, and includes the question of whether two smooth quintic surface
s can intersect in a singular rational curve. We will explore whether gaug
e theory might be a tool that can be used to explore these questions.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Danny Calegari (University of Chicago)
DTSTART:20200512T140000Z
DTEND:20200512T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/2
DESCRIPTION:Title: Taut foliations leafwise branch cover the 2-sphere\nby Danny Cale
gari (University of Chicago) as part of Regensburg low-dimensional geometr
y and topology seminar\n\n\nAbstract\nA co-oriented foliation of an orient
ed 3-manifold is taut if and only if there is a map from the 3-manifold to
the 2-sphere which is a branched cover when restricted to each leaf. I sh
all give two proofs of this theorem and explain its relation to theorems o
f Ghys and Donaldson.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Richard Webb (University of Manchester)
DTSTART:20200519T140000Z
DTEND:20200519T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/3
DESCRIPTION:Title: Quasimorphisms on diffeomorphism groups\nby Richard Webb (Univers
ity of Manchester) as part of Regensburg low-dimensional geometry and topo
logy seminar\n\n\nAbstract\nI will explain how to construct an unbounded q
uasimorphism on the group of isotopically-trivial diffeomorphisms of a sur
face of positive genus. As a corollary the commutator length and fragmenta
tion norm are both (stably) unbounded\, which solves a problem of Burago--
Ivanov--Polterovich. The proof uses a new hyperbolic graph on which these
groups act by isometries\, which is inspired by techniques from mapping cl
ass groups. This is joint work with Jonathan Bowden and Sebastian Hensel.\
n
LOCATION:https://stable.researchseminars.org/talk/rlgts/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zhenkun Li (MIT)
DTSTART:20200526T140000Z
DTEND:20200526T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/4
DESCRIPTION:Title: Instanton Floer homology and the depth of taut foliations\nby Zhe
nkun Li (MIT) as part of Regensburg low-dimensional geometry and topology
seminar\n\n\nAbstract\nSutured manifold hierarchy is a powerful tool intro
duced by Gabai to study the topology of 3-manifolds. The length of a sutur
ed manifold hierarchy gives us a measurement of how complicated the suture
d manifold is. Also\, using this tool\, Gabai proved the existence of fini
te depth taut foliations. However\, he didn’t discuss how finite the dep
th could be.\nSutured Instanton Floer homology was introduced by Kronheime
r and Mrowka and is defined on balanced sutured manifolds. In this talk\,
I will explain how sutured instanton Floer homology could offer us bounds
for the minimal length of a sutured hierarchy and the minimal depth of a f
oliation on a fixed balanced sutured manifold.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Boyu Zhang (Princeton)
DTSTART:20200609T140000Z
DTEND:20200609T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/5
DESCRIPTION:by Boyu Zhang (Princeton) as part of Regensburg low-dimensiona
l geometry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gordana Matic (Univ. of Georgia/MPIM Bonn)
DTSTART:20200616T140000Z
DTEND:20200616T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/6
DESCRIPTION:Title: Spectral order invariant and obstruction to Stein fillability\nby
Gordana Matic (Univ. of Georgia/MPIM Bonn) as part of Regensburg low-dime
nsional geometry and topology seminar\n\n\nAbstract\nIn this joint work wi
th Cagatay Kutluhan\, Jeremy Van Horn- Morris and Andy Wand\, we define an
invariant of contact structures in dimension three arising from introduc
ing a filtration on the boundary operator in Heegaard Floer homology. Thi
s invariant takes values in the set $\\Z_{\\geq0}\\cup\\{\\infty\\}$. It i
s zero for overtwisted contact structures\, $\\infty$ for Stein fillable c
ontact structures\, non-decreasing under Legendrian surgery\, and computab
le from any supporting open book decomposition. I will give the definition
and discuss computability of the invariant. As an application\, we give
an easily computable obstruction to Stein fillability on closed contact 3
-manifolds with non-vanishing Ozsváth-Szabó contact class.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Kathryn Mann (Cornell)
DTSTART:20200630T140000Z
DTEND:20200630T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/7
DESCRIPTION:Title: Large-scale geometry of big mapping class groups\nby Kathryn Mann
(Cornell) as part of Regensburg low-dimensional geometry and topology sem
inar\n\n\nAbstract\nMapping class groups of infinite type surfaces are not
finitely generated (nor even are they locally compact) groups\, but in ma
ny cases one can still meaningfully talk about their large scale geometry.
I will explain joint work with Kasra Rafi on the problem of which surface
s have mapping class groups with nontrivial coarse geometry\, and how this
relates to questions of actions on arc and curve complexes.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mikhail Khovanov (Columbia University)
DTSTART:20200707T140000Z
DTEND:20200707T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/8
DESCRIPTION:Title: From SL(2) to GL(N) foam evaluation\nby Mikhail Khovanov (Columbi
a University) as part of Regensburg low-dimensional geometry and topology
seminar\n\n\nAbstract\nFoams in 3-space are cobordisms between planar grap
hs that are heavily used in link homology theories. In this talk we'll exp
lain how foam theory can be built from the ground up starting with an eval
uation of closed foams\, for SL(2) foams\, then GL(2) foams\, and finally
GL(N) foams for any N. The talk is based on joint work with Louis-Hadrien
Robert and on L.-H. Robert and Emmanuel Wagner's work on foam evaluation.\
n
LOCATION:https://stable.researchseminars.org/talk/rlgts/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claudius Zibrowius (UBC Vancouver)
DTSTART:20200714T140000Z
DTEND:20200714T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/9
DESCRIPTION:Title: Thin links and Conway spheres\nby Claudius Zibrowius (UBC Vancouv
er) as part of Regensburg low-dimensional geometry and topology seminar\n\
n\nAbstract\nWhen does Dehn surgery along a knot give an L-space? More gen
erally\, when does splicing two knot complements give an L-space? Hanselma
n\, Rasmussen and Watson gave very compelling answers to these questions u
sing their technology of immersed curves for three-manifolds with torus bo
undary. Similar invariants have been developed for four-ended tangles. We
use those invariants to study various notions of thinness in both Heegaard
Floer and Khovanov homology from the perspective of tangle decompositions
along Conway spheres. Interestingly\, our results bear strong resemblance
to the aforementioned results about L-spaces. Also\, we observe strong si
milarities between Heegaard Floer and Khovanov homology that lead us to as
k: What is a thin link? This is joint work with Artem Kotelskiy and Liam W
atson.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lisa Piccirillo (MIT)
DTSTART:20200623T140000Z
DTEND:20200623T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/10
DESCRIPTION:Title: The trace embedding lemma and PL surfaces\nby Lisa Piccirillo (M
IT) as part of Regensburg low-dimensional geometry and topology seminar\n\
n\nAbstract\n4-manifold topologists have long been interested in understan
ding smooth (resp. topological) embedded surfaces in smooth (resp. topolog
ical) 4-manifolds\, and as such have developed rich suites of tools for ob
structing the existence of smooth (resp. topological) surfaces. Understand
ing PL surfaces in smooth 4-manifolds has historically garnered less inter
est\, but several problems about PL surfaces have recently arisen in moder
n lines of questioning. Presently there are far fewer tools available to o
bstruct PL surfaces. In this talk\, I’ll discuss how to use a classical
observation\, called the trace embedding lemma\, to repurpose smooth surfa
ce obstructions as PL surface obstructions. I’ll discuss applications of
these retooled obstructions to problems about spinelessness\, exotica\, a
nd geometrically simply connectedness. This is joint work with Kyle Hayden
.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marc Lackenby (University of Oxford)
DTSTART:20200721T140000Z
DTEND:20200721T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/11
DESCRIPTION:Title: Knot genus in a fixed 3-manifold\nby Marc Lackenby (University o
f Oxford) as part of Regensburg low-dimensional geometry and topology semi
nar\n\n\nAbstract\nThe genus of a knot is the minimal genus of any of its
Seifert surfaces. This is a fundamental measure of a knot's complexity. It
generalises naturally to homologically trivial knots in an arbitrary 3-ma
nifold. Agol\, Hass and Thurston showed that the problem of determining th
e genus of a knot in a 3-manifold is hard. More specifically\, the problem
of showing that the genus is at most some integer g is NP-complete. Hence
\, the problem of showing that the genus is exactly some integer g is not
in NP\, assuming a standard conjecture in complexity theory. On the other
hand\, I proved that the problem of determining the genus of a knot in the
3-sphere is in NP. In my talk\, I will discuss the problem of determining
knot genus in a fixed 3-manifold. I will outline why this problem is also
in NP\, which is joint work with Mehdi Yazdi. The proof involves the comp
utation of the Thurston norm ball for knot exteriors.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marco Marengon (MPIM Bonn)
DTSTART:20201103T150000Z
DTEND:20201103T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/12
DESCRIPTION:Title: Non-orientable knot cobordisms and torsion order in Floer homologies
\nby Marco Marengon (MPIM Bonn) as part of Regensburg low-dimensional
geometry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Louis-Hadrien Robert (Université du Luxembourg)
DTSTART:20201117T150000Z
DTEND:20201117T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/13
DESCRIPTION:Title: Categorification of 1 and of the Alexander polynomial\nby Louis-
Hadrien Robert (Université du Luxembourg) as part of Regensburg low-dimen
sional geometry and topology seminar\n\n\nAbstract\nI'll give a combinator
ial and down-to-earth definition of the symmetric gl(1) homology. It is a
(non-trivial) link homology which categorifies the trivial link invariant
(equal to 1 on every link). Then I'll explain how to use this construction
to obtain colored categorification of the Alexander polynomial. (joint wi
th E. Wagner)\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sarah Rasmussen (University of Cambridge)
DTSTART:20201124T150000Z
DTEND:20201124T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/14
DESCRIPTION:Title: Taut foliations from left orders in Heegaard genus 2\nby Sarah R
asmussen (University of Cambridge) as part of Regensburg low-dimensional g
eometry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tao Li (Boston College)
DTSTART:20201201T150000Z
DTEND:20201201T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/15
DESCRIPTION:by Tao Li (Boston College) as part of Regensburg low-dimension
al geometry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ciprian Manolescu (Stanford University)
DTSTART:20201208T150000Z
DTEND:20201208T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/16
DESCRIPTION:Title: Relative genus bounds in indefinite four-manifolds\nby Ciprian M
anolescu (Stanford University) as part of Regensburg low-dimensional geome
try and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Masaki Taniguchi (Riken)
DTSTART:20201110T150000Z
DTEND:20201110T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/17
DESCRIPTION:Title: Filtered instanton Floer homology and the 3-dimensional homology cob
ordism group\nby Masaki Taniguchi (Riken) as part of Regensburg low-di
mensional geometry and topology seminar\n\n\nAbstract\nWe introduce a fami
ly of real-valued homology cobordism invariants $r_s(Y)$ of oriented homol
ogy 3-spheres. The invariants $r_s(Y)$ are based on a quantitative constru
ction of filtered instanton Floer homology. Using our invariants\, we give
several new constraints of the set of smooth boundings of homology 3-sphe
res. As one of the corollaries\, we give infinitely many homology 3-sphere
s which cannot bound any definite 4-manifold. As another corollary\, we sh
ow that if the 1-surgery of a knot has negative Froyshov invariant\, then
the $1/n$-surgeries ($n>0$) of the knot are linearly independent in the ho
mology cobordism group. This is joint work with Yuta Nozaki and Kouki Sato
.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Siddhi Krishna (Georgia Tech)
DTSTART:20201215T150000Z
DTEND:20201215T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/18
DESCRIPTION:Title: Taut foliations and Dehn surgery along positive braid knots\nby
Siddhi Krishna (Georgia Tech) as part of Regensburg low-dimensional geomet
ry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:tba
DTSTART:20201222T150000Z
DTEND:20201222T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/19
DESCRIPTION:by tba as part of Regensburg low-dimensional geometry and topo
logy seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Paul Feehan (Rutgers)
DTSTART:20210119T150000Z
DTEND:20210119T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/21
DESCRIPTION:Title: Morse-Bott theory on analytic spaces and applications to topology of
smooth 4-manifolds\nby Paul Feehan (Rutgers) as part of Regensburg lo
w-dimensional geometry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Daniel Ruberman (Brandeis)
DTSTART:20210126T150000Z
DTEND:20210126T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/22
DESCRIPTION:Title: The diffeomorphism group of a 4-manifold\nby Daniel Ruberman (Br
andeis) as part of Regensburg low-dimensional geometry and topology semina
r\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Luisa Paoluzzi (University of Aix-Marseille)
DTSTART:20210202T150000Z
DTEND:20210202T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/23
DESCRIPTION:Title: Cyclic branched covers of alternating knots\nby Luisa Paoluzzi (
University of Aix-Marseille) as part of Regensburg low-dimensional geometr
y and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Liam Watson (University of British Columbia)
DTSTART:20210209T150000Z
DTEND:20210209T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/24
DESCRIPTION:Title: Symmetry and mutation\nby Liam Watson (University of British Col
umbia) as part of Regensburg low-dimensional geometry and topology seminar
\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nick Salter (Columbia)
DTSTART:20210216T150000Z
DTEND:20210216T161500Z
DTSTAMP:20260404T111103Z
UID:rlgts/25
DESCRIPTION:Title: r-spin mapping class groups and applications\nby Nick Salter (Co
lumbia) as part of Regensburg low-dimensional geometry and topology semina
r\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Guillem Cazassus (Oxford)
DTSTART:20210427T140000Z
DTEND:20210427T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/26
DESCRIPTION:Title: The earring correspondence of the pillowcase\nby Guillem Cazassu
s (Oxford) as part of Regensburg low-dimensional geometry and topology sem
inar\n\n\nAbstract\nSingular instanton homology is a knot invariant introd
uced by Kronheimer and Mrowka. It is deeply tied to Khovanov homology\, an
d among other things\, permits to show that the latter detects the unknot.
\n\nIn order to compute singular instanton homology\, Hedden\, Herald and
Kirk defined a symplectic (Atiyah-Floer) analogue\, called pillowcase homo
logy. This is a Lagrangian Floer homology in the traceless character varie
ty of the four-punctured sphere.\n\nWe study the Lagrangian correspondence
induced by the earring tangle\, an essential ingredient in Kronheimer-Mro
wka's construction. Our computation suggests that figure eight bubbling
— a subtle degeneration phenomenon predicted by Bottman and Wehrheim —
appears in the context of traceless character varieties. This is joint wo
rk with Chris Herald\, Paul Kirk and Artem Kotelskiy.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Zoltán Szabó (Princeton)
DTSTART:20210504T140000Z
DTEND:20210504T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/27
DESCRIPTION:Title: Knot Floer homology constructions and the Pong Algebra\nby Zolt
án Szabó (Princeton) as part of Regensburg low-dimensional geometry and
topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:John Baldwin (Boston College)
DTSTART:20210511T140000Z
DTEND:20210511T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/28
DESCRIPTION:Title: Instanton L-spaces and splicing\nby John Baldwin (Boston College
) as part of Regensburg low-dimensional geometry and topology seminar\n\nA
bstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cameron Gordon (UT Austin)
DTSTART:20210608T140000Z
DTEND:20210608T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/29
DESCRIPTION:Title: Toroidal 3-manifolds and the properties in the L-space Conjecture\nby Cameron Gordon (UT Austin) as part of Regensburg low-dimensional geo
metry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Steven Frankel (Washington University in St. Louis)
DTSTART:20210713T140000Z
DTEND:20210713T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/30
DESCRIPTION:by Steven Frankel (Washington University in St. Louis) as part
of Regensburg low-dimensional geometry and topology seminar\n\nAbstract:
TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Arunima Ray (MPIM Bonn)
DTSTART:20210601T140000Z
DTEND:20210601T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/31
DESCRIPTION:Title: A surface embedding theorem\nby Arunima Ray (MPIM Bonn) as part
of Regensburg low-dimensional geometry and topology seminar\n\nAbstract: T
BA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonathan Zung (Princeton)
DTSTART:20210706T140000Z
DTEND:20210706T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/32
DESCRIPTION:Title: Reeb flows transverse to foliations\nby Jonathan Zung (Princeton
) as part of Regensburg low-dimensional geometry and topology seminar\n\n\
nAbstract\nEliashberg and Thurston showed that (roughly) $C^2$ taut foliat
ions on 3-manifolds can be approximated by tight contact structures. I wil
l explain a new approach to this theorem which allows one to control the r
esulting Reeb flow and hence produce many hypertight contact structures. A
long the way\, I will explain how harmonic transverse measures may be used
to understand the holonomy of foliations.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Alexandra Kjuchukova (Notre Dame)
DTSTART:20210629T140000Z
DTEND:20210629T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/33
DESCRIPTION:Title: Covers of S^3 bounding covers of B^4\nby Alexandra Kjuchukova (N
otre Dame) as part of Regensburg low-dimensional geometry and topology sem
inar\n\n\nAbstract\nLet $G$ be a group\, $K$ a knot and $\\rho$ a surjecti
ve homomorphism $\\pi_1(S^3 \\backslash K) \\to G$. When does a branched c
over of $S^3$ determined by $\\rho$ extend over $B^4$\, with a smooth bran
ching locus $F$? Previously\, the answer was only known under quite strong
assumptions\, e.g. when K is slice and G a dihedral group. I will define
a new invariant which detects the existence of such an extension for all k
nots and all metabelian groups. I will give examples of computing the obst
ruction and constructing the desired surface $F$. Joint work with Kent Orr
.\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rostislav Akhmechet (University of Virginia)
DTSTART:20210518T140000Z
DTEND:20210518T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/34
DESCRIPTION:Title: Anchored foams and annular homology\nby Rostislav Akhmechet (Uni
versity of Virginia) as part of Regensburg low-dimensional geometry and to
pology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:no talk
DTSTART:20210525T140000Z
DTEND:20210525T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/35
DESCRIPTION:by no talk as part of Regensburg low-dimensional geometry and
topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Barthelmé (Queen's University)
DTSTART:20210615T140000Z
DTEND:20210615T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/36
DESCRIPTION:by Thomas Barthelmé (Queen's University) as part of Regensbur
g low-dimensional geometry and topology seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/36/
END:VEVENT
BEGIN:VEVENT
SUMMARY:tba
DTSTART:20210622T140000Z
DTEND:20210622T151500Z
DTSTAMP:20260404T111103Z
UID:rlgts/37
DESCRIPTION:by tba as part of Regensburg low-dimensional geometry and topo
logy seminar\n\nAbstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/rlgts/37/
END:VEVENT
END:VCALENDAR