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BEGIN:VEVENT
SUMMARY:Allison Moore (Virginia Commonwealth University)
DTSTART;VALUE=DATE-TIME:20200908T180000Z
DTEND;VALUE=DATE-TIME:20200908T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/1
DESCRIPTION:Title: Triple linking and Heegaard Floer homology.\nby Allison
Moore (Virginia Commonwealth University) as part of Brandeis Topology Sem
inar\n\n\nAbstract\nWe will describe several appearances of Milnor’s inv
ariants in the link Floer complex. This will include a formula that expres
ses the Milnor triple linking number in terms of the h-function. We will a
lso show that the triple linking number is involved in a structural proper
ty of the d-invariants of surgery on certain algebraically split links. We
will apply the above properties toward new detection results for the Borr
omean and Whitehead links. This is joint work with Gorsky\, Lidman and Liu
.\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Abdul Zalloum (Queen's University)
DTSTART;VALUE=DATE-TIME:20200915T180000Z
DTEND;VALUE=DATE-TIME:20200915T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/2
DESCRIPTION:Title: Regularity of Morse geodesics and growth of stable subg
roups\nby Abdul Zalloum (Queen's University) as part of Brandeis Topology
Seminar\n\n\nAbstract\nThe study of groups with "hyperbolic-like direction
s" has been a central theme in geometric group theory. Two notions are usu
ally used to quantify what is meant by "hyperbolic-like directions''\, the
notion of a contracting geodesic and that of a Morse geodesic. Since the
property that every geodesic ray in metric space X is contracting or Morse
characterizes hyperbolic spaces\, being a contracting/Morse geodesic is c
onsidered a hyperbolic-like property. In more general spaces\, the Morse p
roperty is strictly weaker than the contracting property. However\, if on
e adds an additional “local-to-global” condition on X\, then Morse geo
desics behave much like geodesics in hyperbolic spaces. Generalizing work
of Cannon\, I will first discuss a joint result with Eike proving that fo
r any finitely generated group\, the language of contracting geodesics wit
h a fixed parameter is a regular language. I will then talk about recent w
ork with Cordes\, Russell and Spriano where we show that in local-to-globa
l spaces\, Morse geodesics also form a regular language\, and we give a ch
aracterization of stable subgroups in terms of regular languages.\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ivan Levcovitz (Technion)
DTSTART;VALUE=DATE-TIME:20200922T180000Z
DTEND;VALUE=DATE-TIME:20200922T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/3
DESCRIPTION:Title: Characterizing divergence in right-angled Coxeter group
s\nby Ivan Levcovitz (Technion) as part of Brandeis Topology Seminar\n\n\n
Abstract\nA main goal in geometric group theory is to understand finitely
generated groups up to quasi-isometry (a coarse geometric equivalence rela
tion on Cayley graphs). Right-angled Coxeter groups (RACGs) are a well-stu
died\, wide class of groups whose coarse geometry is not well understood.
One of the few available quasi-isometry invariants known to distinguish no
n-relatively hyperbolic RACGs is the divergence function\, which roughly m
easures the maximum rate that a pair of geodesic rays in a Cayley graph ca
n diverge from one another. In this talk I will discuss a recent result th
at completely classifies divergence functions in RACGs\, gives a simple me
thod of computing them and links divergence to other known quasi-isometry
invariants.\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ahmad Issa (University of British Columbia)
DTSTART;VALUE=DATE-TIME:20200929T180000Z
DTEND;VALUE=DATE-TIME:20200929T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/4
DESCRIPTION:by Ahmad Issa (University of British Columbia) as part of Bran
deis Topology Seminar\n\nAbstract: TBA\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Elia Fioravante (Max Planck Institute\, Bonn)
DTSTART;VALUE=DATE-TIME:20201006T180000Z
DTEND;VALUE=DATE-TIME:20201006T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/5
DESCRIPTION:Title: Cubulations determined by their length function\nby Eli
a Fioravante (Max Planck Institute\, Bonn) as part of Brandeis Topology Se
minar\n\n\nAbstract\nThe theory of group actions on CAT(0) cube complexes
has exerted a strong influence on geometric group theory and low-dimension
al topology in the last two decades. Indeed\, knowing that a group G acts
properly and cocompactly on a CAT(0) cube complex reveals a lot of its alg
ebraic structure. However\, in general\, "cubulations" are non-canonical a
nd the group G can act on cube complexes in many different ways. It is thu
s natural to attempt to classify all such actions for a fixed group G\, id
eally obtaining a good notion of "space of all cubulations of G". As a fir
st step\, we show that G-actions on CAT(0) cube complexes are often comple
tely determined by their length function. This yields a simple topology on
this space and a natural compactification resembling Thurston's compactif
ication of Teichmüller space. Based on joint works with J. Beyrer and M.
Hagen.\n\nhttps://brandeis.zoom.us/j/99772088777\n\nPassword hint: negativ
ely curved (in algebra and geometry)\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:David Duncan (James Madison University)
DTSTART;VALUE=DATE-TIME:20201013T180000Z
DTEND;VALUE=DATE-TIME:20201013T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/6
DESCRIPTION:Title: Bundle splittings on boundary-punctured disks\nby David
Duncan (James Madison University) as part of Brandeis Topology Seminar\n\
n\nAbstract\nOver a Riemann surface\, a bundle pair is a holomorphic bundl
e together with a totally real subbundle on the boundary. A result of Oh s
tates that\, over a disk\, a bundle pair splits as a sum of line bundle pa
irs. We discuss work-in-progress that seeks to extend Oh's result to bound
ary-punctured disks. The strategy is to use the Yang--Mills gradient flow
for singular connections to identify the relevant bundle isomorphism.\nhtt
ps://brandeis.zoom.us/j/99772088777\n\nPassword hint: negatively curved (i
n algebra and geometry)\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jonathan Simone (UMass Amherst)
DTSTART;VALUE=DATE-TIME:20201020T180000Z
DTEND;VALUE=DATE-TIME:20201020T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/7
DESCRIPTION:Title: Using rational homology circles to construct rational h
omology balls\nby Jonathan Simone (UMass Amherst) as part of Brandeis Topo
logy Seminar\n\n\nAbstract\nMotivated by Akbulut-Larson's construction of
Brieskorn spheres bounding rational homology 4-balls\, we explore plumbed
3-manifolds that bound rational homology circles and use them to construct
infinite families of rational homology 3-spheres that bound rational homo
logy 4-balls. In particular\, we will classify torus bundles over the circ
le that bound rational homology circles and provide a simple method for co
nstructing more general plumbed 3-manifolds that bound rational homology c
ircles. We then use these rational homology circles to show that\, for exa
mple\, -1-surgery along any twisted positively-clasped Whitehead double of
any knot bounds a rational homology 4-ball.\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Amitesh Datta (Princeton University)
DTSTART;VALUE=DATE-TIME:20201027T180000Z
DTEND;VALUE=DATE-TIME:20201027T193000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/8
DESCRIPTION:Title: Is the braid group $B_4$ a group of $3\\times 3$-matric
es?\nby Amitesh Datta (Princeton University) as part of Brandeis Topology
Seminar\n\n\nAbstract\nThe Burau representation is a classical linear repr
esentation of the braid group that can be used to define the Alexander pol
ynomial invariant for knots and links. \n\nThe question of whether or not
the Burau representation of the braid group $B_4$ is faithful is an open p
roblem since the 1930s. The faithfulness of this representation is necessa
ry for the Jones polynomial of a knot to detect the unknot.\n\nIn this tal
k\, I will present my work on this problem\, which includes strong constra
ints on the kernel of this representation. The key techniques include a ne
w interpretation of the Burau matrix of a positive braid and a new decompo
sition of positive braids into subproducts.\n\nI will discuss all of the r
elevant background for the problem from scratch and illustrate my techniqu
es through simple examples. I will also highlight the beautiful and elegan
t connections to bowling balls and quantum intersection numbers of simple
closed curves on punctured disks.\n
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chris Scaduto (University of Miami)
DTSTART;VALUE=DATE-TIME:20201103T190000Z
DTEND;VALUE=DATE-TIME:20201103T203000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/9
DESCRIPTION:Title: Equivariant singular instanton homology\nby Chris Scadu
to (University of Miami) as part of Brandeis Topology Seminar\n\nInteracti
ve livestream: https://brandeis.zoom.us/j/99772088777\nPassword hint: hint
negatively curved (in algebra and geometry)\n\nAbstract\nEvery knot is th
e boundary of a normally immersed disk in the 4-ball. The 4D clasp number
of a knot is the minimal number of double points over all such immersed di
sks. In this talk I will explain how certain equivariant cohomological con
structions in singular instanton Floer theory lead to new results for 4D c
lasp numbers and unknotting numbers of knots. This is joint work with Ali
Daemi.\n
URL:https://brandeis.zoom.us/j/99772088777
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ceren Kose (UT Austin)
DTSTART;VALUE=DATE-TIME:20201110T190000Z
DTEND;VALUE=DATE-TIME:20201110T203000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/10
DESCRIPTION:by Ceren Kose (UT Austin) as part of Brandeis Topology Seminar
\n\nInteractive livestream: https://brandeis.zoom.us/j/99772088777\nPasswo
rd hint: negatively curved (in algebra and geometry)\nAbstract: TBA\n
URL:https://brandeis.zoom.us/j/99772088777
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bülent Tosun (University of Alabama)
DTSTART;VALUE=DATE-TIME:20201117T190000Z
DTEND;VALUE=DATE-TIME:20201117T203000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/11
DESCRIPTION:by Bülent Tosun (University of Alabama) as part of Brandeis T
opology Seminar\n\nInteractive livestream: https://brandeis.zoom.us/j/9977
2088777\nPassword hint: negatively curved (in algebra and geometry)\nAbstr
act: TBA\n
URL:https://brandeis.zoom.us/j/99772088777
END:VEVENT
BEGIN:VEVENT
SUMMARY:Carolyn Abbott (Columbia University)
DTSTART;VALUE=DATE-TIME:20201201T190000Z
DTEND;VALUE=DATE-TIME:20201201T203000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/12
DESCRIPTION:by Carolyn Abbott (Columbia University) as part of Brandeis To
pology Seminar\n\nInteractive livestream: https://brandeis.zoom.us/j/99772
088777\nPassword hint: negatively curved (in algebra and geometry)\nAbstra
ct: TBA\n
URL:https://brandeis.zoom.us/j/99772088777
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yulan Qing (Fudan University)
DTSTART;VALUE=DATE-TIME:20201208T190000Z
DTEND;VALUE=DATE-TIME:20201208T203000Z
DTSTAMP;VALUE=DATE-TIME:20201029T113402Z
UID:BrandeisTopology/13
DESCRIPTION:Title: The Large Scale Geometry of Big Mapping Class Groups\nb
y Yulan Qing (Fudan University) as part of Brandeis Topology Seminar\n\nIn
teractive livestream: https://brandeis.zoom.us/j/99772088777\nPassword hin
t: negatively curved (in algebra and geometry)\nAbstract: TBA\n
URL:https://brandeis.zoom.us/j/99772088777
END:VEVENT
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