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BEGIN:VEVENT
SUMMARY:Otis Chodosh (Stanford)
DTSTART:20201020T134500Z
DTEND:20201020T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/1
DESCRIPTION:Title: Generic regularity of min-max minimal hypersurfaces in eight dimension
s\nby Otis Chodosh (Stanford) as part of B.O.W.L Geometry Seminar\n\nA
bstract: TBA\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Colleen Robles (Duke)
DTSTART:20201027T134500Z
DTEND:20201027T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/2
DESCRIPTION:Title: Completions of period mappings\nby Colleen Robles (Duke) as part o
f B.O.W.L Geometry Seminar\n\n\nAbstract\nIt’s a long standing problem i
n Hodge theory to complete the image of a period map. The latter arise in
the study of algebraic moduli\, and are proper holomorphic maps into loca
lly homogeneous spaces that are subject to a differential constraint. I
’ll give a survey of the problem and then describe recent progress\, wit
h an emphasis on the role of complex geometry and Lie theory. Joint with
Mark Green and Phillip Griffiths.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Marco Guaraco (Imperial)
DTSTART:20201103T134500Z
DTEND:20201103T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/3
DESCRIPTION:Title: Multiplicity one of generic stable Allen-Cahn minimal hypersurfaces\nby Marco Guaraco (Imperial) as part of B.O.W.L Geometry Seminar\n\n\nAb
stract\nAllen-Cahn (AC) minimal hypersurfaces are limits of nodal sets of
solutions to the AC equation. An important problem is to understand the lo
cal picture of this convergence. For instance\, can we avoid the situation
in which the nodal set looks like a multigraph over the limit hypersurfac
e? General examples of this phenomenon\, known as “multiplicity” or "i
nterface foliation”\, exist when the limit hypersurface is unstable. To
gether with A. Neves and F. Marques we proved that\, generically and in al
l dimensions\, these are the only possible examples of interface foliation
\, i.e. generic stable AC minimal hypersurfaces can only occur with multip
licity one. We will discuss this and other topics.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tristan Ozuch-Meersseman (MIT)
DTSTART:20201110T134500Z
DTEND:20201110T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/4
DESCRIPTION:Title: Higher order obstructions to the desingularization of Einstein metrics
\nby Tristan Ozuch-Meersseman (MIT) as part of B.O.W.L Geometry Semina
r\n\n\nAbstract\nWe exhibit new obstructions to the desingularization of E
instein metrics in dimension 4. These obstructions are specific to the com
pact situation and raise the question of whether or not a sequence of Eins
tein metrics degenerating while bubbling out gravitational instantons has
to be Kähler-Einstein. We then test these obstructions to discuss the pos
sibility of producing a Ricci-flat but not Kähler metric by the promising
desingularization configuration proposed by Page in 1981.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jean-Pierre Demailly (Institut Fourier)
DTSTART:20201117T134500Z
DTEND:20201117T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/5
DESCRIPTION:Title: Hermitian-Yang-Mills approach to the conjecture of Griffiths on the po
sitivity of ample vector bundles\nby Jean-Pierre Demailly (Institut Fo
urier) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nGiven a vector b
undle of arbitrary rank with ample determinant line\nbundle on a projectiv
e manifold\, we propose a new elliptic system of\ndifferential equations o
f Hermitian-Yang-Mills type for the curvature\ntensor. The system is desi
gned so that solutions provide Hermitian\nmetrics with positive curvature
in the sense of Griffiths – and even\nin the dual Nakano sense. As a con
sequence\, if an existence result\ncould be obtained for every ample vecto
r bundle\, the Griffiths\nconjecture on the equivalence between ampleness
and positivity of\nvector bundles would be settled. Another outcome of the
approach is a\nnew concept of volume for vector bundles.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dario Beraldo (University College London)
DTSTART:20201124T134500Z
DTEND:20201124T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/6
DESCRIPTION:Title: On the geometry of Bun_G near infinity\nby Dario Beraldo (Universi
ty College London) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nLet
Bun_G be the moduli stack of G-bundles on a compact Riemann surface. After
reviewing (and motivating) the notion of "temperedness" appearing in the
geometric Langlands program\, I will discuss the proof of a conjecture of
Gaitsgory stating that the constant D-module on Bun_G is anti-tempered. No
prior familiarity with geometric Langlands will be assumed\; rather\, I'l
l emphasize some key ingredients that might be of broader interest: a Serr
e duality in an unusual context and various cohomology vanishing computati
ons.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jasmin Hörter (Karlsruhe)
DTSTART:20201201T134500Z
DTEND:20201201T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/7
DESCRIPTION:Title: Limits of epsilon-harmonic maps\nby Jasmin Hörter (Karlsruhe) as
part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIn 1981 Sacks and Uhlenbec
k introduced their famous alpha-approximation of the Dirichlet energy for
maps from surfaces and showed that critical points converge to a harmonic
map (away from finitely many points). Now one can ask whether every harmon
ic map is captured by this limiting process. Lamm\, Malchiodi and Micallef
answered this for maps from the two sphere into the two sphere and showed
that the Sacks-Uhlenbeck method produces only constant maps and rotations
if the energy lies below a certain threshold. We investigate the same que
stion for the epsilon-approximation of the Dirichlet energy.\nJoint work w
ith Tobias Lamm and Mario Micallef.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nikon Kurnosov (University College London)
DTSTART:20201208T134500Z
DTEND:20201208T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/8
DESCRIPTION:Title: Deformation theory and geometry of Bogomolov-Guan manifolds\nby Ni
kon Kurnosov (University College London) as part of B.O.W.L Geometry Semin
ar\n\n\nAbstract\nIn 1994\, Guan published a series of papers constructing
non-Kähler holomorphic symplectic manifolds\, challenging a conjecture b
y Todorov. These examples\, called now BG manifolds were given a more tran
sparent presentation by Bogomolov in 96 which emphasizes the analogy with
Kodaira-Thurston example of non-Kähler symplectic surfaces. We will discu
ss some important properties of BG manifolds: the deformation theory which
is quite similar to that of hyperkahler case\, algebraic reduction and su
bmanifolds.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Casey Kelleher (Princeton)
DTSTART:20201215T134500Z
DTEND:20201215T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/9
DESCRIPTION:Title: Gap Theorem Results in Yang--Mills Theory\nby Casey Kelleher (Prin
ceton) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nWe discuss resul
ts concerning the space of Yang--Mills connections on vector bundles over
compact 4-dimensional Riemannian manifolds. In particular\, we discuss a c
onformally invariant gap theorem for Yang-Mills connections obtained by ex
ploiting an associated Yamabe-type problem. We also discuss a bound for th
e index in terms of its energy which is conformally invariant\, which capt
ures the sharp growth rate. This is joint work with M. Gursky and J. Stree
ts.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fritz Hiesmayr (UCL)
DTSTART:20210119T134500Z
DTEND:20210119T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/10
DESCRIPTION:Title: A Bernstein-type theorem for two-valued minimal graphs in dimension f
our\nby Fritz Hiesmayr (UCL) as part of B.O.W.L Geometry Seminar\n\n\n
Abstract\nThe Bernstein theorem is a classical result for minimal graphs.
It states that\na globally defined solution of the minimal surface equatio
n on $\\mathbb{R}^n$ must be linear\,\nprovided the dimension is small eno
ugh. We present an analogous theorem for\ntwo-valued minimal graphs\, vali
d in dimension four. By definition two-valued\nfunctions take values in th
e unordered pairs of real numbers\; they arise as the\nlocal model of bran
ch point singularities. The plan is to juxtapose this with the\nclassical
single-valued theory\, and explain where some of the difficulties emerge\n
in the two-valued setting.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Theodora Bourni (Tennessee)
DTSTART:20210126T134500Z
DTEND:20210126T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/11
DESCRIPTION:Title: Ancient solutions to mean curvature flow\nby Theodora Bourni (Ten
nessee) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nMean curvature
flow (MCF) is the gradient flow of the area functional\; it moves the surf
ace in the direction of steepest decrease of area. An important motivatio
n for the study of MCF comes from its potential geometric applications\, s
uch as classification theorems and geometric inequalities. MCF develops
“singularities” (curvature blow-up)\, which obstruct the flow from exi
sting for all times and therefore understanding these high curvature regio
ns is of great interest. This is done by studying ancient solutions\, sol
utions that have existed for all times in the past\, and which model singu
larities. In this talk we will discuss their importance and ways of constr
ucting and classifying such solutions. In particular\, we will focus on
“collapsed” solutions and construct\, in all dimensions $n\\geq 2$\, a
large family of new examples\, including both symmetric and asymmetric ex
amples\, as well as many eternal examples that do not evolve by translatio
n. Moreover\, we will show that collapsed solutions decompose “backward
s in time” into a canonical configuration of Grim hyperplanes which sati
sfies certain necessary conditions. This is joint work with Mat Langford a
nd Giuseppe Tinaglia.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chao Li (Princeton)
DTSTART:20210202T134500Z
DTEND:20210202T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/12
DESCRIPTION:Title: Scalar curvature on aspherical manifolds\nby Chao Li (Princeton)
as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIt has been a classical
question which manifolds admit Riemannian metrics with positive scalar cu
rvature. I will first review some history of this question\, and present s
ome recent progress\, ruling out positive scalar curvature on closed asphe
rical manifolds of dimensions 4 and 5 (as conjectured by Schoen-Yau and by
Gromov). I will also discuss some related questions including the Urysohn
width inequalities on manifolds with scalar curvature lower bounds. This
talk is based on joint work with Otis Chodosh.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Claude LeBrun (Stony Brook)
DTSTART:20210216T134500Z
DTEND:20210216T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/14
DESCRIPTION:Title: Anti-self-dual 4-manifolds\, quasi-Fuchsian groups\, and almost Kähl
er geometry\nby Claude LeBrun (Stony Brook) as part of B.O.W.L Geometr
y Seminar\n\n\nAbstract\nIt is known that the almost-Kähler anti-self-dua
l metrics on a given 4-manifold sweep out an open subset in the moduli spa
ce of anti-self-dual metrics. However\, we show by example that this subse
t is not generally closed\, and does not always sweep out entire connected
components in the moduli space. The construction hinges on an unexpected
link between harmonic functions on certain hyperbolic 3-manifolds and self
-dual harmonic 2-forms on associated 4-manifolds.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Eleonora Di Nezza (École Polytechnique)
DTSTART:20210223T134500Z
DTEND:20210223T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/15
DESCRIPTION:Title: Families of Kähler-Einstein metrics\nby Eleonora Di Nezza (Écol
e Polytechnique) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIn a l
ot of geometric situation we need to work with families of varieties. In t
his talk we focus on families of singular Kähler-Einstein metric. In part
icular we study the case of a family of Kähler varieties and we develop t
he first steps of pluripotential theory in family\, which will allow us to
have a control on the $C^0$ estimate when the complex structure varies. T
his type of result will be applied in different geometric contexts. This i
s a joint work with V. Guedj and H. Guenancia.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gábor Székelyhidi (Notre Dame)
DTSTART:20210302T134500Z
DTEND:20210302T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/16
DESCRIPTION:Title: Uniqueness of certain cylindrical tangent cones\nby Gábor Széke
lyhidi (Notre Dame) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nLeo
n Simon showed that if an area minimizing hypersurface admits a cylindrica
l tangent cone of the form $C \\times \\mathbb{R}$\, then this tangent con
e is unique for a large class of minimal cones $C$. One of the hypotheses
in this result is that $C \\times \\mathbb{R}$ is integrable and this excl
udes the case when $C$ is the Simons cone over $S^3\\times S^3$. The main
result in this talk is that the uniqueness of the tangent cone holds in th
is case too. The new difficulty in this non-integrable situation is to dev
elop a version of the Lojasiewicz-Simon inequality that can be used in the
setting of tangent cones with non-isolated singularities.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Richard Bamler (Berkeley)
DTSTART:20210309T170000Z
DTEND:20210309T180000Z
DTSTAMP:20260404T094547Z
UID:BOWL/17
DESCRIPTION:Title: Compactness and partial regularity theory of Ricci flows in higher di
mensions\nby Richard Bamler (Berkeley) as part of B.O.W.L Geometry Sem
inar\n\n\nAbstract\nWe present a new compactness theory of Ricci flows. Th
is theory states that any sequence of Ricci flows that is pointed in an ap
propriate sense\, subsequentially converges to a synthetic flow. Under a n
atural non-collapsing condition\, this limiting flow is smooth on the comp
lement of a singular set of parabolic codimension at least 4. We furthermo
re obtain a stratification of the singular set with optimal dimensional bo
unds depending on the symmetries of the tangent flows. Our methods also im
ply the corresponding quantitative stratification result and the expected
$L^p$-curvature bounds.\n\nAs an application we obtain a description of t
he singularity formation at the first singular time and a long-time charac
terization of immortal flows\, which generalizes the thick-thin decomposit
ion in dimension 3. We also obtain a backwards pseudolocality theorem and
discuss several other applications.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Robin Neumayer (Northwestern)
DTSTART:20210316T134500Z
DTEND:20210316T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/18
DESCRIPTION:Title: $d_p$ Convergence and $\\varepsilon$-regularity theorems for entropy
and scalar curvature lower bounds\nby Robin Neumayer (Northwestern) as
part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIn this talk\, we conside
r Riemannian manifolds with almost non-negative scalar curvature and Perel
man entropy. We establish an $\\varepsilon$-regularity theorem showing tha
t such a space must be close to Euclidean space in a suitable sense. Inter
estingly\, such a result is false with respect to the Gromov-Hausdorff and
Intrinsic Flat distances\, and more generally the metric space structure
is not controlled under entropy and scalar lower bounds. Instead\, we intr
oduce the notion of the $d_p$ distance between (in particular) Riemannian
manifolds\, which measures the distance between $W^{1\,p}$ Sobolev spaces\
, and it is with respect to this distance that the epsilon regularity theo
rem holds. We will discuss various applications to manifolds with scalar c
urvature and entropy lower bounds\, including a compactness and limit stru
cture theorem for sequences\, a uniform $L^\\infty$ Sobolev embedding\, an
d a priori $L^p$ scalar curvature bounds for $p<1$. This is joint work wit
h Man-Chun Lee and Aaron Naber.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yi Lai (Berkeley)
DTSTART:20210323T134500Z
DTEND:20210323T144500Z
DTSTAMP:20260404T094547Z
UID:BOWL/19
DESCRIPTION:Title: A family of 3d steady gradient solitons that are flying wings\nby
Yi Lai (Berkeley) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nWe f
ind a family of 3d steady gradient Ricci solitons that are flying wings. T
his verifies a conjecture by Hamilton. For a 3d flying wing\, we show that
the scalar curvature does not vanish at infinity. The 3d flying wings are
collapsed. For dimension $n \\geq 4$\, we find a family of $\\mathbb{Z}_2
\\times O(n − 1)$-symmetric but non-rotationally symmetric n-dimensiona
l steady gradient solitons with positive curvature operator. We show that
these solitons are non-collapsed.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ilaria Mondello (Paris-Est Créteil)
DTSTART:20210330T124500Z
DTEND:20210330T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/20
DESCRIPTION:Title: Limits of manifolds with a Kato bound on the Ricci curvature\nby
Ilaria Mondello (Paris-Est Créteil) as part of B.O.W.L Geometry Seminar\n
\n\nAbstract\nStarting from Gromov pre-compactness theorem\, a vast theory
about the structure of limits of manifolds with a lower bound on the Ricc
i curvature has been developed thanks to the work of J. Cheeger\, T.H. Col
ding\, M. Anderson\, G. Tian\, A. Naber\, W. Jiang. Nevertheless\, in some
situations\, for instance in the study of geometric flows\, there is no l
ower bound on the Ricci curvature. It is then important to understand what
happens when having a weaker condition. \n\nIn this talk\, we present new
results about limits of manifolds with a Kato bound on the negative part
of the Ricci tensor. Such bound is weaker than the previous $L^p$ bounds c
onsidered in the literature (P. Petesern\, G. Wei\, G. Tian\, Z. Zhang\, C
. Rose\, L. Chen\, C. Ketterer…). In the non-collapsing case\, we recove
r part of the regularity theory that was known in the setting of Ricci low
er bounds: in particular\, we obtain that all tangent cones are metric con
es\, a stratification result and volume convergence to the Hausdorff measu
re. After presenting the setting and main theorem\, we will focus on provi
ng that tangent cones are metric cones\, and in particular on the study of
the appropriate monotone quantities that leads to this result.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rober Haslhofer (Toronto)
DTSTART:20210504T124500Z
DTEND:20210504T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/21
DESCRIPTION:Title: Mean curvature flow through neck-singularities\nby Rober Haslhofe
r (Toronto) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIn this tal
k\, I will explain our recent work showing that mean curvature flow throug
h neck-singularities is unique. The key is a classification result for anc
ient asymptotically cylindrical flows that describes all possible blowup l
imits near a neck-singularity. In particular\, this confirms Ilmanen’s m
ean-convex neighborhood conjecture\, and more precisely gives a canonical
neighborhood theorem for neck-singularities. Furthermore\, assuming the mu
ltiplicity-one conjecture\, we conclude that for embedded two-spheres mean
curvature flow through singularities is well-posed. The two-dimensional c
ase is joint work with Choi and Hershkovits\, and the higher-dimensional c
ase is joint with Choi\, Hershkovits and White.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gilles Carron (Nantes)
DTSTART:20210511T124500Z
DTEND:20210511T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/22
DESCRIPTION:Title: Rigidity of the Euclidean heat kernel\nby Gilles Carron (Nantes)
as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIt is a joint work with
David Tewodrose (Bruxelles) https://arxiv.org/abs/1912.10759. I will expl
ain that a metric measure space with Euclidean heat kernel is Euclidean.
An almost rigidity result comes then for free\, and this can be used to g
ive another proof of Colding’s almost rigidity for complete manifold wit
h non negative Ricci curvature and almost Euclidean growth.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Yevgeny Liokumovich (Toronto)
DTSTART:20210518T124500Z
DTEND:20210518T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/23
DESCRIPTION:Title: Foliations of 3-manifolds of positive scalar curvature by surfaces of
controlled size\nby Yevgeny Liokumovich (Toronto) as part of B.O.W.L
Geometry Seminar\n\n\nAbstract\nLet M be a compact 3-manifold with scalar
curvature at least 1. We show that there exists a Morse function f on M\,
such that every connected component of every fiber of f has genus\, area a
nd diameter bounded by a universal constant. The proof uses Min-Max theory
and Mean Curvature Flow. This is a joint work with Davi Maximo. Time perm
itting\, I will discuss a related problem for macroscopic scalar curvature
in metric spaces (joint with Boris Lishak\, Alexander Nabutovsky and Regi
na Rotman).\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Costante Bellettini (UCL)
DTSTART:20210525T124500Z
DTEND:20210525T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/24
DESCRIPTION:Title: Existence of hypersurfaces with prescribed mean-curvature\nby Cos
tante Bellettini (UCL) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\n
Let N be a compact Riemannian manifold of dimension 3 or higher\, and g a
Lipschitz non-negative (or non-positive) function on N. We prove that ther
e exists a closed hypersurface M whose mean curvature attains the values p
rescribed by g (joint work with Neshan Wickramasekera\, Cambridge). Except
possibly for a small singular set (of codimension 7 or higher)\, the hype
rsurface M is C^2 immersed and two-sided (it admits a global unit normal)\
; the scalar mean curvature at x is g(x) with respect to a global choice o
f unit normal. More precisely\, the immersion is a quasi-embedding\, namel
y the only non-embedded points are caused by tangential self-intersections
: around such a non-embedded point\, the local structure is given by two d
isks\, lying on one side of each other\, and intersecting tangentially (as
in the case of two spherical caps touching at a point). A special case of
PMC (prescribed-mean-curvature) hypersurfaces is obtained when g is a con
stant\, in which the above result gives a CMC (constant-mean-curvature) hy
persurface for any prescribed value of the mean curvature. The constructio
n of M is carried out largely by means of PDE principles: (i) a minmax for
an Allen–Cahn (or Modica-Mortola) energy\, involving a parameter that\,
when sent to 0\, leads to an interface from which the desired PMC hypersu
rface is extracted\; (ii) quasi-linear elliptic PDE and geometric-measure-
theory arguments\, to obtain regularity conclusions for said interface\; (
iii) parabolic semi-linear PDE (together with specific features of the All
en-Cahn framework)\, to tackle cancellation phenomena that can happen when
sending to 0 the Allen-Cahn parameter.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hans-Joachim Hein (Münster)
DTSTART:20210601T124500Z
DTEND:20210601T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/25
DESCRIPTION:Title: Smooth asymptotics for collapsing Calabi-Yau metrics\nby Hans-Joa
chim Hein (Münster) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nI
will present recent joint work with Valentino Tosatti in which we obtain a
complete asymptotic expansion (locally uniformly away from the singular f
ibers) of Calabi-Yau metrics collapsing along a holomorphic fibration of a
fixed compact Calabi-Yau manifold. The result is weaker than a standard a
symptotic expansion in that the coefficient functions might still depend o
n the small parameter in some unknown way in the base variables. However\,
it is far stronger in that all terms including the remainder at each orde
r are proved to be uniformly bounded in C^k for all k. We also calculate t
he first nontrivial coefficient in terms of the Kodaira-Spencer forms of t
he fibration.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anna Siffert (Münster)
DTSTART:20210608T124500Z
DTEND:20210608T134500Z
DTSTAMP:20260404T094547Z
UID:BOWL/26
DESCRIPTION:Title: Construction of explicit p-harmonic functions\nby Anna Siffert (M
ünster) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nThe study of p
-harmonic functions on Riemannian manifolds has invoked the interest of ma
thematicians and physicists for nearly two centuries. Applications within
physics can for example be found in continuum mechanics\, elasticity theor
y\, as well as two-dimensional hydrodynamics problems involving Stokes flo
ws of incompressible Newtonian fluids. In my talk I will focus on the cons
truction of explicit p-harmonic functions on rank-one Lie groups of Iwasaw
a type. This joint wok with Sigmundur Gudmundsson and Marko Sobak.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Laura Fredrickson (Oregon)
DTSTART:20210615T150000Z
DTEND:20210615T160000Z
DTSTAMP:20260404T094547Z
UID:BOWL/27
DESCRIPTION:Title: ALG Gravitational Instantons and Hitchin Moduli Spaces\nby Laura
Fredrickson (Oregon) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nFo
ur-dimensional complete hyperkaehler manifolds can be classified into ALE\
, ALF\, ALG\, ALG*\, ALH\, ALH* families. It has been conjectured that ev
ery ALG or ALG* hyperkaehler metric can be realized as a 4d Hitchin moduli
space. I will describe ongoing work with Rafe Mazzeo\, Jan Swoboda\, and
Hartmut Weiss to prove a special case of the conjecture\, and some conseq
uences. The hyperkaehler metrics on Hitchin moduli spaces are of independ
ent interest\, as the physicists Gaiotto—Moore—Neitzke give an intrica
te conjectural description of their asymptotic geometry.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martin Taylor (Imperial)
DTSTART:20211005T130000Z
DTEND:20211005T140000Z
DTSTAMP:20260404T094547Z
UID:BOWL/28
DESCRIPTION:Title: The nonlinear stability of the Schwarzschild family of black holes\nby Martin Taylor (Imperial) as part of B.O.W.L Geometry Seminar\n\n\nAb
stract\nI will present a theorem on the full finite codimension nonlinear
asymptotic stability of the Schwarzschild family of black holes. The proof
employs a double null gauge\, is expressed entirely in physical space\, a
nd utilises the analysis of Dafermos–Holzegel–Rodnianski on the linear
stability of the Schwarzschild family. This is joint work with M. Dafermo
s\, G. Holzegel and I. Rodnianski.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christoph Böhm (Münster)
DTSTART:20211019T130000Z
DTEND:20211019T140000Z
DTSTAMP:20260404T094547Z
UID:BOWL/29
DESCRIPTION:Title: Non-compact Einstein manifolds with symmetry\nby Christoph Böhm
(Münster) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nFor Einstein
manifolds with negative scalar curvature admitting an isometric action of
a Lie group G with compact\, smooth orbit space\, we show the following r
igidity result:\nThe nilradical N of G acts polarly and the N-orbits are l
ocally isometric to a nilsoliton.\nApplications will be discussed. This is
joint work with R. Lafuente.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thomas Koerber (Vienna)
DTSTART:20211102T140000Z
DTEND:20211102T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/30
DESCRIPTION:Title: Foliations of asymptotically flat 3-manifolds by stable constant mean
curvature spheres\nby Thomas Koerber (Vienna) as part of B.O.W.L Geom
etry Seminar\n\n\nAbstract\nStable constant mean curvature spheres encode
important information on the asymptotic geometry of initial data sets for
isolated gravitational systems. In this talk\, I will present a short new
proof (joint with M. Eichmair) based on Lyapunov-Schmidt reduction of the
existence of an asymptotic foliation of such an initial data set by stable
constant mean curvature spheres. In the case where the scalar curvature i
s non-negative\, our method also shows that the leaves of this foliation a
re the only large stable constant mean curvature spheres that enclose the
center of the initial data set.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/30/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christina Sormani (CUNY)
DTSTART:20211116T140000Z
DTEND:20211116T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/31
DESCRIPTION:Title: VF convergence and scalar curvature\nby Christina Sormani (CUNY)
as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nWe will present a colle
ction of conjectures formulated with Gromov and other members of our IAS E
merging Topics Working Group on the limits of sequences of Riemannian mani
folds with uniform lower bounds on their scalar curvature. We will survey
results in special cases and present key theorems concerning volume preser
ving intrinsic flat convergence that have been applied to prove these spec
ial cases. For a complete list of papers about intrinsic flat convergence
see https://sites.google.com/site/intrinsicflatconvergence/.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/31/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Panagiota Daskalopoulos (Columbia)
DTSTART:20211130T140000Z
DTEND:20211130T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/32
DESCRIPTION:Title: Type II smoothing in Mean curvature flow\nby Panagiota Daskalopou
los (Columbia) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nIn 1994
Velázquez constructed a smooth $O(4)\\times O(4)$ invariant Mean Curvatur
e Flow that forms a type-II singularity at the origin in space-time. Rece
ntly\, Stolarski showed that the mean curvature on this solution is unifor
mly bounded. Earlier\, Velázquez also provided formal asymptotic expansi
ons for a possible smooth continuation of the solution after the singulari
ty. \n \nJointly with S. Angenent and N. Sesum we establish the short time
existence of Velázquez' formal continuation\, and we verify that the mea
n curvature is also uniformly bounded on the continuation. Combined with t
he earlier results of Velázquez–Stolarski we therefore show that there
exists a solution $\\left\\{ M_t^7\\subset \\mathbb{R}^8 | -t_0 < t < t_0\
\right\\}$ that has an isolated singularity at the origin $0$ in $\\mathbb
{R}^8$\, and at $t=0$\; moreover\, the mean curvature is uniformly bounded
on this solution\, even though the second fundamental form is unbounded n
ear the singularity.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/32/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ilyas Khan (Oxford)
DTSTART:20211214T140000Z
DTEND:20211214T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/33
DESCRIPTION:Title: The structure of mean curvature flow translators with finite total cu
rvature\nby Ilyas Khan (Oxford) as part of B.O.W.L Geometry Seminar\n\
n\nAbstract\nIn the mean curvature flow\, translating solutions are an imp
ortant model for singularity formation. In this talk\, we will consider th
e class of 2-dimensional mean curvature flow translators embedded in $\\ma
thbb{R}^3$ which have finite total curvature and describe their asymptotic
structure\, which turns out to be highly rigid. I will outline the proof
of this asymptotic description\, in particular focusing on some novel and
unexpected features of the proof.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/33/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lucas Ambrozio (IMPA)
DTSTART:20220125T140000Z
DTEND:20220125T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/34
DESCRIPTION:Title: Analogues of Zoll surfaces in minimal surface theory\nby Lucas Am
brozio (IMPA) as part of B.O.W.L Geometry Seminar\n\n\nAbstract\nAbout 121
years ago\, Otto Zoll described a large family of rotationally symmetric
Riemannian two-dimensional spheres whose geodesics are all closed and have
the same period. Since then\, a very rich (but yet incomplete) theory dev
eloped in order to construct and understand geometries (in a broad sense)
with these special geodesic flows\, also in higher dimensions. \n\nAfter w
orking on certain systolic questions about minimal two-dimensional spheres
in three-dimensional Riemannian spheres with R. Montezuma (UFC)\, and mot
ivated by other interesting geometric reasons\, I became convinced that an
other sort of higher dimensional generalisation of Zoll surfaces\, within
the theory of minimal submanifolds\, deserved to be investigated on its ow
n. In this talk\, we will report on some of the results we proved about th
ese new objects\, including existence results\, together with F. Codá Mar
ques (Princeton) and A. Neves (UChicago).\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/34/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mikhail Karpukhin (Caltech)
DTSTART:20220322T140000Z
DTEND:20220322T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/35
DESCRIPTION:Title: Optimization of Laplace and Steklov eigenvalues with applications to
minimal surfaces\nby Mikhail Karpukhin (Caltech) as part of B.O.W.L Ge
ometry Seminar\n\n\nAbstract\nThe study of optimal upper bounds for Laplac
e eigenvalues on closed surfaces is a classical problem of spectral geomet
ry going back to J. Hersch\, P. Li and S.-T. Yau. Its most fascinating fea
ture is the connection to the theory of minimal surfaces in spheres. Optim
ization of Steklov eigenvalues is an analogous problem on surfaces with bo
undary. It was popularised by A. Fraser and R. Schoen\, who discovered its
connection to the theory of free boundary surfaces in Euclidean balls. De
spite many widely-known empiric parallels\, an explicit link between the t
wo problems was discovered only in the last two years. In the present talk
\, we will show how Laplace eigenvalues can be recovered as certain limits
of Steklov eigenvalues and discuss the applications of this construction
to the geometry of minimal surfaces. The talk is based on joint works with
D. Stern.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/35/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tristan Ozuch (MIT)
DTSTART:20220215T140000Z
DTEND:20220215T150000Z
DTSTAMP:20260404T094547Z
UID:BOWL/36
DESCRIPTION:Title: Weighted versions of scalar curvature\, mass and spin geometry for Ri
cci flows\nby Tristan Ozuch (MIT) as part of B.O.W.L Geometry Seminar\
n\n\nAbstract\nWith A. Deruelle\, we define a Perelman like functional for
ALE metrics which lets us study the (in)stability of Ricci-flat ALE metri
cs. With J. Baldauf\, we extend some classical objects and formulas from t
he study of scalar curvature\, spin geometry and general relativity to man
ifolds with densities. We surprisingly find that the extension of ADM mass
is the opposite of the above functional introduced with A. Deruelle. Thro
ugh a weighted Witten’s formula\, this functional also equals a weighted
spinorial Dirichlet energy on spin manifolds. Ricci flow is the gradient
flow of all of these quantities.\n
LOCATION:https://stable.researchseminars.org/talk/BOWL/36/
END:VEVENT
END:VCALENDAR