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BEGIN:VEVENT
SUMMARY:Olivier Glorieux (IHES)
DTSTART;VALUE=DATE-TIME:20200519T140000Z
DTEND;VALUE=DATE-TIME:20200519T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/1
DESCRIPTION:Title: Critical exponents in higher rank symmetric spaces\nby Olivier Glorie
ux (IHES) as part of Pangolin seminar\n\n\nAbstract\nThe aim of the talk i
s to present some recent results on critical exponents for discrete subgro
ups of higher rank semisimple Lie groups. We will survey classical results
in negative curvature\, the relationship with entropy and the Hausdorff d
imension of limit sets. Then we will introduce the geometric properties of
higher rank symmetric spaces and explain the main differences with strict
negative curvature. We will focus on two different results : the behaviou
r of the critical exponent under normal subgroup (j.w. S. Tapie) and the e
xtension of classical results to pseudo-riemannian geometry (j.w. D. Moncl
air).\n
LOCATION:https://researchseminars.org/talk/Geometry/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Roman Prosanov (Technische Universität Wien)
DTSTART;VALUE=DATE-TIME:20200602T140000Z
DTEND;VALUE=DATE-TIME:20200602T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/2
DESCRIPTION:Title: Rigidity of compact Fuchsian manifolds with convex boundary\nby Roman
Prosanov (Technische Universität Wien) as part of Pangolin seminar\n\n\n
Abstract\nBy a compact Fuchsian manifold with boundary we mean a hyperboli
c 3-manifold homeomorphic to $S_g \\times [0\; 1]$ such that the boundary
component $S_g \\times \\{ 0\\}$ is geodesic. Here $S_g$ is a closed orien
ted surface of genus $g>1$. Fuchsian manifolds are known as toy cases in t
he study of geometry of hyperbolic 3-manifolds with boundary. In my talk I
will sketch a proof that a compact Fuchsian manifold with convex boundary
is uniquely determined by the induced path metric on $S_g \\times \\{1\\}
$. We do not put further restrictions on the boundary except convexity. Th
is unifies two previously known results: in the case of smooth boundary su
ch a result follows from a work of Schlenker and in the case of polyhedral
boundary it was proven by Fillastre.\n
LOCATION:https://researchseminars.org/talk/Geometry/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gabriel Calsamiglia (Universidade Federal Fluminense)
DTSTART;VALUE=DATE-TIME:20200616T140000Z
DTEND;VALUE=DATE-TIME:20200616T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/3
DESCRIPTION:Title: Spaces of isoperiodic holomorphic and meromorphic differentials\nby G
abriel Calsamiglia (Universidade Federal Fluminense) as part of Pangolin s
eminar\n\n\nAbstract\nI will present some results on the topology of the s
paces of holomorphic and meromorphic one forms over complex curves for whi
ch integration along certain homology classes is constant.\n
LOCATION:https://researchseminars.org/talk/Geometry/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Andrea Seppi (Université Grenoble Alpes)
DTSTART;VALUE=DATE-TIME:20200714T140000Z
DTEND;VALUE=DATE-TIME:20200714T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/4
DESCRIPTION:Title: The Gauss map for nearly-Fuchsian manifolds\nby Andrea Seppi (Univers
ité Grenoble Alpes) as part of Pangolin seminar\n\n\nAbstract\nIn this ta
lk we will study the Gauss map for nearly-Fuchsian manifolds\, namely comp
lete hyperbolic n-manifolds homeomorphic to HxR\, where H is a closed hype
rsurface with principal curvatures smaller than one in absolute value. The
Gauss map of such a hypersurface is a Lagrangian equivariant embedding in
the space of oriented geodesics of hyperbolic space\, which is known to h
ave a natural para-Kähler structure. We will present two characterization
s of the Lagrangian equivariant embeddings obtained in this way\, the firs
t in terms of the vanishing of the Maslov class\, and the second in terms
of orbits of the group of Hamiltonian symplectomorphisms.\n\nThis is joint
work with Christian El Emam (Pavia).\n
LOCATION:https://researchseminars.org/talk/Geometry/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Dmitry Faifman (Tel-Aviv Universty)
DTSTART;VALUE=DATE-TIME:20200728T140000Z
DTEND;VALUE=DATE-TIME:20200728T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/6
DESCRIPTION:Title: Intrinsic volumes of submanifolds of normed spaces: How intrinsic are the
y?\nby Dmitry Faifman (Tel-Aviv Universty) as part of Pangolin seminar
\n\n\nAbstract\nThe intrinsic volumes\, or quermassintegrals\, are certain
geometric functionals on sufficiently nice subsets of Euclidean space\, g
iven by the coefficients of the volume of an epsilon-tube of the set\, whi
ch is a polynomial in epsilon. H. Weyl discovered that their value on a Ri
emannian submanifold of Euclidean space is\, remarkably\, an intrinsic inv
ariant of the metric. We will consider the setting of a normed space\, whe
re the Holmes-Thompson intrinsic volumes are available\, and attempt to ex
tend Weyl's result to Finsler submanifolds. \nBased on a joint work with T
. Wannerer.\n
LOCATION:https://researchseminars.org/talk/Geometry/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Graham Smith (Universidade Federal do Rio de Janeiro)
DTSTART;VALUE=DATE-TIME:20200630T140000Z
DTEND;VALUE=DATE-TIME:20200630T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/8
DESCRIPTION:Title: On eternal forced mean curvature flows of tori in perturbations of the un
it sphere\nby Graham Smith (Universidade Federal do Rio de Janeiro) as
part of Pangolin seminar\n\n\nAbstract\nUsing a singular perturbation arg
ument based on the work of B. White\, we construct eternal mean curvature
flows of tori in perturbations of the standard unit 3-sphere. Besides bein
g of interest in the theory of mean curvature flows\, such objects have ap
plications in Morse homology theory. A large part of the proof involves th
e construction of certain types of functions of Morse-Smale type over the
moduli space of Clifford tori. This has interesting potential applications
to the theory of Radon transformations. This is joint work with Claudia S
alas Mangaño.\n
LOCATION:https://researchseminars.org/talk/Geometry/8/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gilles Carron (Université de Nantes)
DTSTART;VALUE=DATE-TIME:20200825T140000Z
DTEND;VALUE=DATE-TIME:20200825T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/9
DESCRIPTION:Title: The index theorem for manifolds with cusps\nby Gilles Carron (Univers
ité de Nantes) as part of Pangolin seminar\n\n\nAbstract\nI will speak on
the result obtained with W. Ballmann and J. Brüning about index theorem
on manifold with cusps :\n\n-Eigenvalues and holonomy. Int. Math. Res. Not
. 2003\, no. 12\, 657–665.\n\n-Regularity and index theory for Dirac-Sch
rödinger systems with Lipschitz coefficients.\n\nJ. Math. Pures Appl. (9)
89 (2008)\, no. 5\, 429–476.\n\n-Index theorems on manifolds with strai
ght ends. Compos. Math. 148 (2012)\, no. 6\, 1897–1968.\n\nI will start
with a review of the case of compact manifolds and manifolds with cylindri
cal ends (i.e. the work of Atiyah-Patodi-Singer) and then describe the mai
n technical difficulties we had to face.\n
LOCATION:https://researchseminars.org/talk/Geometry/9/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Martín Reiris (Universidad de la República\, Montevideo)
DTSTART;VALUE=DATE-TIME:20200908T133000Z
DTEND;VALUE=DATE-TIME:20200908T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/10
DESCRIPTION:Title: On the existence of Killing fields in smooth spacetimes with a compact C
auchy horizon\nby Martín Reiris (Universidad de la República\, Monte
video) as part of Pangolin seminar\n\n\nAbstract\nWe prove that the surfac
e gravity of a compact non-degenerate Cauchy horizon in a smooth vacuum sp
acetime\, can be normalized to a non-zero constant. This result\, combined
with a recent result by Oliver Petersen and István Rácz\, end up provin
g the Isenberg-Moncrief\nconjecture on the existence of Killing fields\, i
n the smooth differentiability class. The well known corollary of this\, i
n accordance with the strong cosmic censorship conjecture\, is that the pr
esence of compact Cauchy horizons is a non-generic phenomenon.\nThough we
work in 3+1\, the result is valid line by line in any n+1-dimensions.\n
LOCATION:https://researchseminars.org/talk/Geometry/10/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thibault Leveufre (Université Paris-Sud)
DTSTART;VALUE=DATE-TIME:20200922T140000Z
DTEND;VALUE=DATE-TIME:20200922T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/11
DESCRIPTION:Title: Marked length spectrum\, geodesic stretch and pressure metric\nby Th
ibault Leveufre (Université Paris-Sud) as part of Pangolin seminar\n\n\nA
bstract\nThe marked length spectrum of a negatively-curved manifold is t
he data of all the lengths of closed geodesics\, marked by the free homoto
py of the manifold. The marked length spectrum conjecture (also known as t
he Burns-Katok conjecture\, 1985) asserts that two negatively-curved manif
olds with same marked length spectrum should be isometric. This conjecture
was proved on surfaces (Croke '90\, Otal '90) but remains open in higher
dimensions. I will present a proof of a local version of this conjecture\,
based on the notions of geodesic stretch and pressure metric (a gener
alization of the Weil-Petersson metric to the context of variable curvatur
e). Some elements of the theory of Pollicott-Ruelle resonances and anisotr
opic spaces will also be needed (I will recall everything). Joint work wit
h C. Guillarmou and G. Knieper.\n
LOCATION:https://researchseminars.org/talk/Geometry/11/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stéphane Sabourau (Université Parsi-Est Créteil)
DTSTART;VALUE=DATE-TIME:20201006T140000Z
DTEND;VALUE=DATE-TIME:20201006T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/12
DESCRIPTION:Title: Geometric semi-norms in homology\nby Stéphane Sabourau (Université
Parsi-Est Créteil) as part of Pangolin seminar\n\n\nAbstract\nThe simpli
cial volume of a simplicial complex is a topological invariant related to
the growth of the fundamental group\, which gives rise to a semi-norm in h
omology. In this talk\, we introduce the volume entropy semi-norm\, which
is also related to the growth of the fundamental group of simplicial compl
exes and shares functorial properties with the simplicial volume. Answerin
g a question of Gromov\, we prove that the volume entropy semi-norm is equ
ivalent to the simplicial volume semi-norm in every dimension. Joint work
with I. Babenko.\n
LOCATION:https://researchseminars.org/talk/Geometry/12/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Filippo Mazzoli (University of Virginia)
DTSTART;VALUE=DATE-TIME:20201103T140000Z
DTEND;VALUE=DATE-TIME:20201103T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/13
DESCRIPTION:Title: Constant Gaussian curvature surfaces in hyperbolic 3-manifolds\nby F
ilippo Mazzoli (University of Virginia) as part of Pangolin seminar\n\n\nA
bstract\nIn this talk I will describe how constant Gaussian curvature (CGC
) surfaces interpolate the structures of the pleated boundary of the conve
x core and of the boundary at infinity of a geometrically finite hyperboli
c end\, and I will present a series of consequences of this phenomenon: a
description of the renormalized volume of a quasi-Fuchsian manifold in ter
ms of its CGC-foliation\, a characterization of the immersion data of CGC-
surfaces of a hyperbolic end as an integral curve of a time-dependent Hami
ltonian vector field on the cotangent space to Teichmüller space\, and a
consequent generalization of McMullen’s Kleinian reciprocity theorem.\n
LOCATION:https://researchseminars.org/talk/Geometry/13/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Premoselli (Université Libre de Bruxelles)
DTSTART;VALUE=DATE-TIME:20201020T140000Z
DTEND;VALUE=DATE-TIME:20201020T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/14
DESCRIPTION:Title: Glueing constructions of Compact Einstein four-manifolds with negative s
ectional\nby Bruno Premoselli (Université Libre de Bruxelles) as part
of Pangolin seminar\n\n\nAbstract\nWe construct examples of closed Einste
in four-manifolds with negative sectional curvature. We describe two main
families of examples which are respectively obtained as ramified covers an
d smooth quotients of ``large’’ hyperbolic 4-manifolds with symmetries
. The first family of examples is sometimes referred to as Gromov-Thurston
manifolds. The Einstein metrics that we construct are the result of a glu
eing procedure. They are obtained as deformations of an approximate Einste
in metric which is an interpolation between a ``black-hole – type’’
Riemannian Einstein metric near the symmetry locus and the hyperbolic metr
ic. This construction yields the first example of compact Einstein manifo
lds with negative sectional curvature which are not locally homogeneous. T
his is a joint work with J. Fine (ULB\, Brussels).\n
LOCATION:https://researchseminars.org/talk/Geometry/14/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Duc-Manh Nguyen (Université de Bordeaux)
DTSTART;VALUE=DATE-TIME:20201117T140000Z
DTEND;VALUE=DATE-TIME:20201117T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/15
DESCRIPTION:Title: Variation of Hodge structure and enumerating triangulations and quadrang
ulations of surfaces\nby Duc-Manh Nguyen (Université de Bordeaux) as
part of Pangolin seminar\n\n\nAbstract\nSince the work of Eskin-Okounkov (
in 2001)\, it has been known that in any stratum of translation surfaces t
he number of square-tiled surafces constructed from at most n squares gro
ws like $c\\pi^{2g}n^d$\, where $d$ is the (complex) dimension of the stra
tum\, $g$ is the genus of the surfaces\, and $c$ is a rational number. Sim
ilar phenomenon also occurs in strata of quadratic differentials. Counting
square-tiled surfaces in a given stratum is more or less the same as coun
ting quadrangulations of a topological surface\, with some prescribed cond
itions on the singularities and the holonomy of the associated flat metric
. More recently\, Engel showed that the asymptotics of the numbers of quad
rangulations and triangulations\, satisfying some prescribed conditions at
the singularities\, with at most $n$ tiles are of the form $\\alpha n^d$\
, where $\\alpha$ is a constant in $Q[\\pi]$ or $Q[\\sqrt{3}\\pi]$.\nIn th
is talk\, we will explain how the asymptotics above can be related to the
computation of the volume of some moduli spaces\, and how one can show tha
t in some situations the constant $\\alpha$ belongs actually to either $Q\
\cdot\\pi^d$\, or $Q\\cdot(\\sqrt{3}\\pi)^d$ by using tools from complex a
lgebraic geometry. This is joint work with Vincent Koziarz.\n
LOCATION:https://researchseminars.org/talk/Geometry/15/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jérémy Toulisse (Université de Nice-Sophia Antipolis)
DTSTART;VALUE=DATE-TIME:20201201T140000Z
DTEND;VALUE=DATE-TIME:20201201T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/16
DESCRIPTION:Title: Plateau problem in the pseudo-hyperbolic space\nby Jérémy Toulisse
(Université de Nice-Sophia Antipolis) as part of Pangolin seminar\n\n\nA
bstract\nThe pseudo-hyperbolic space H^{2\,n} is the pseudo-Riemannian ana
logue of the classical hyperbolic space. In this talk\, I will explain how
to solve an asymptotic Plateau problem in this space: given a topological
circle in the boundary at infinity of H^{2\,n}\, we construct a unique co
mplete maximal surface bounded by this circle. This construction relies on
Gromov’s theory of pseudo-holomorphic curves. This is a joint work with
François Labourie and Mike Wolf.\n
LOCATION:https://researchseminars.org/talk/Geometry/16/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ben Lowe (Princeton University)
DTSTART;VALUE=DATE-TIME:20201215T140000Z
DTEND;VALUE=DATE-TIME:20201215T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/17
DESCRIPTION:Title: Minimal Surfaces in Negatively Curved 3-Manifolds and Dynamics\nby B
en Lowe (Princeton University) as part of Pangolin seminar\n\n\nAbstract\n
The Grassmann bundle of tangent 2-planes over a closed hyperbolic 3-manifo
ld M has a natural foliation by (lifts by their tangent planes of) immerse
d totally geodesic planes in M. I am going to talk about work I’ve done
on constructing foliations whose leaves are (lifts of) minimal surfaces in
a metric on M of negative sectional curvature\, which are deformations of
the totally geodesic foliation described above. These foliations make it
possible to use homogeneous dynamics to study how closed minimal surfaces
in variable negative curvature are distributed in the ambient 3-manifold.
Many of the ideas here come from recent work of Calegari-Marques-Neves\, w
hich I will also talk about. I was able to establish some preliminary fact
s about the dynamics of these foliations\, but much remains to be understo
od.\n
LOCATION:https://researchseminars.org/talk/Geometry/17/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jason Lotay (Oxford University)
DTSTART;VALUE=DATE-TIME:20210126T150000Z
DTEND;VALUE=DATE-TIME:20210126T160000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/18
DESCRIPTION:Title: Deformed G2 instantons\nby Jason Lotay (Oxford University) as part o
f Pangolin seminar\n\n\nAbstract\nDeformed G2-instantons are special conne
ctions occurring in G2 geometry in 7 dimensions. They arise as “mirrors
” to certain calibrated cycles\, providing an analogue to deformed Hermi
tian-Yang-Mills connections\, and are critical points of a Chern-Simons-ty
pe functional. I will describe an elementary construction of the first non
-trivial examples of deformed G2-instantons\, and their relation to 3-Sasa
kian geometry\, nearly parallel G2-structures\, isometric G2-structures\,
obstructions in deformation theory\, the topology of the moduli space\, an
d the Chern-Simons-type functional.\n
LOCATION:https://researchseminars.org/talk/Geometry/18/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Christian El Emam (Université du Luxembourg)
DTSTART;VALUE=DATE-TIME:20210209T140000Z
DTEND;VALUE=DATE-TIME:20210209T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/19
DESCRIPTION:Title: Families of equivariant immersions in $H^3$ with holomorphic holonomy\nby Christian El Emam (Université du Luxembourg) as part of Pangolin se
minar\n\n\nAbstract\nGiven an equivariant immersion of a surface in the hy
perbolic 3-space\, a typical problem consists in understanding whether a d
eformation of the immersion (parametrized over a complex manifold) produce
s a holomorphic deformation of its mondromy in PSL(2\,C). In this talk we
present a simple “trick” providing a sufficient condition for this pro
perty\, offering for instance an alternative proof of the holomorphicity o
f the complex landslide flow. This result is a consequence of the study of
immersions into the space of geodesics of the hyperbolic 3-space\, seen a
s a holomorphic Riemannian manifold\, whose key features will be discussed
in the talk.\n\nThis is joint work with Francesco Bonsante\n
LOCATION:https://researchseminars.org/talk/Geometry/19/
END:VEVENT
BEGIN:VEVENT
SUMMARY:María Asunción Jiménez (Universidade Federal Fluminense)
DTSTART;VALUE=DATE-TIME:20210223T140000Z
DTEND;VALUE=DATE-TIME:20210223T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/20
DESCRIPTION:Title: Elliptic Linear Weingarten graphs with isolated singularities\nby Ma
ría Asunción Jiménez (Universidade Federal Fluminense) as part of Pango
lin seminar\n\n\nAbstract\nWe study isolated singularities of graphs whose
mean and Gaussian curvature satisfy the elliptic linear relation $2\\alph
a H+\\beta K=1$\, $\\alpha^2+\\beta>0$. This family of surfaces includes c
onvex and non-convex singular surfaces and also cusp-type surfaces. We det
ermine in which cases the singularity is removable\, and classify non-exte
ndable totally isolated singularities in term of regular real analytic str
ictly convex curves in $\\S^2$. This is a joint work with João P. dos San
tos.\n
LOCATION:https://researchseminars.org/talk/Geometry/20/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Barbara Schapira (Université de Rennes I)
DTSTART;VALUE=DATE-TIME:20210309T140000Z
DTEND;VALUE=DATE-TIME:20210309T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/21
DESCRIPTION:Title: Amenability of covers through critical exponents\nby Barbara Schapir
a (Université de Rennes I) as part of Pangolin seminar\n\n\nAbstract\nLet
M be a negatively curved manifold. If M is “strongly positively recurre
nt”\, i.e. there is a critical gap between its entropy at infinity and i
ts entropy\, we show that a cover M' of M is amenable if and only if the c
ritical exponents of M' and M coincide. The proof uses a construction of P
atterson-Sullivan measures twisted by a representation. This is a joint wo
rk with R. Dougall\, R. Coulon and S.Tapie.\n
LOCATION:https://researchseminars.org/talk/Geometry/21/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Louis Merlin (Aachen University)
DTSTART;VALUE=DATE-TIME:20210323T140000Z
DTEND;VALUE=DATE-TIME:20210323T150000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/22
DESCRIPTION:Title: On the relations between the universal Teichmuller space and Anti de Sit
ter geometry\nby Louis Merlin (Aachen University) as part of Pangolin
seminar\n\n\nAbstract\nAnti de Sitter (AdS) space is the Lorentzian cousin
of the hyperbolic 3-space: it is a symmetric space with constant curvatur
e -1. In this talk\, we will consider surface group representations in the
isometry group of AdS space\, called quasi-Fuchsian representations. Ther
e is 2 classical objects associated to those representations and one of th
e goal is to understand their interplay: the limit set which is a quasi-ci
rcle in the boundary at infinity of AdS space and a convex set inside AdS
which is preserved by the group action and bounded by two pleated surfaces
. I will conclude the talk by a report on a work in common with Jean-marc
Schlenker where we extend the "Teichmüller" situation to the "universal T
eichmüller".\n
LOCATION:https://researchseminars.org/talk/Geometry/22/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Leon Carvajales (Université de Paris-Sorbonne Université)
DTSTART;VALUE=DATE-TIME:20210406T133000Z
DTEND;VALUE=DATE-TIME:20210406T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/23
DESCRIPTION:Title: Growth of quadratic forms under Anosov subgroups\nby Leon Carvajales
(Université de Paris-Sorbonne Université) as part of Pangolin seminar\n
\n\nAbstract\nFor positive integers p and q we define a counting problem i
n the (pseudo-Riemannian symmetric) space of quadratic forms of signature
(p\,q) on R^{p+q}. This is done by associating to each quadratic form a ge
odesic copy of the Riemannian symmetric space of PSO(p\,q) inside the Riem
annian symmetric space of PSL_{p+q}(R)\, and by looking at the orbit of th
is geodesic copy under the action of a discrete subgroup of PSL_{p+q}(R).
We then present some contributions to the study of this counting problem f
or Borel-Anosov subgroups of PSL_{p+q}(R).\n
LOCATION:https://researchseminars.org/talk/Geometry/23/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jean-Marc Schlenker (Université du Luxembourg)
DTSTART;VALUE=DATE-TIME:20210420T133000Z
DTEND;VALUE=DATE-TIME:20210420T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/24
DESCRIPTION:Title: The Weyl problem for unbounded convex surfaces in H^3\nby Jean-Marc
Schlenker (Université du Luxembourg) as part of Pangolin seminar\n\n\nAbs
tract\nThe classical Weyl problem in Euclidean space\, solved in the 1950s
\, askswhether any smooth metric of positive curvature on the sphere can b
e realized as the induced metric on the boundary of a unique convex subset
in $\\R^3$. It was extended by Alexandrov to the hyperbolic space\, where
a dual problem can also be considered: prescribing the third fundamental
form of a convex surface.\n\nWe will describe extensions of the Weyl probl
em and its dual to unbounded convex surfaces in $H^3$. Two types of genera
lizations can be stated\, one concerning unbounded convex surfaces\, the o
ther unbounded locally convex surfaces. Both questions have as special cas
es a number of known result or conjectures concerning 3-dimensional hyperb
olic geometry\, circle packings\, etc. We will present a rather general ex
istence result concerning convex subsets.\n
LOCATION:https://researchseminars.org/talk/Geometry/24/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matilde Martínez García (Universidad de la República\, Montevid
eo)
DTSTART;VALUE=DATE-TIME:20210504T133000Z
DTEND;VALUE=DATE-TIME:20210504T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/25
DESCRIPTION:Title: On tilings\, amenable equivalence relations and foliated spaces\nby
Matilde Martínez García (Universidad de la República\, Montevideo) as p
art of Pangolin seminar\n\n\nAbstract\nI will describe a family of foliate
d spaces constructed from tylings on Lie groups. They provide a negative a
nswer to the following question by G.Hector: are leaves of a compact folia
ted space always quasi-isometric to Cayley graphs? Their construction was
motivated by a profound conjecture of Giordano\, Putnam and Skau on the cl
assification\, up to orbit equivalence\, of actions of countable amenable
groups on the Cantor set. I will briefly explain how these examples relate
to the GPS conjecture. This is joint work with Fernando Alcalde Cuesta an
d Álvaro Lozano Rojo.\n
LOCATION:https://researchseminars.org/talk/Geometry/25/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Barbara Nelli (Università dell’Aquila)
DTSTART;VALUE=DATE-TIME:20210518T133000Z
DTEND;VALUE=DATE-TIME:20210518T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/26
DESCRIPTION:Title: The topology of constant mean curvature surfaces with convex boundary\nby Barbara Nelli (Università dell’Aquila) as part of Pangolin semina
r\n\n\nAbstract\nWe discuss old and new results about the shape of a const
ant mean curvature surfaces with strictly convex boundary\, contained in t
he halfspace determined by the surface containing the boundary.\n
LOCATION:https://researchseminars.org/talk/Geometry/26/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Maria del Mar Gonzalez\, (Universidad Autónoma de Madrid)
DTSTART;VALUE=DATE-TIME:20210601T133000Z
DTEND;VALUE=DATE-TIME:20210601T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/27
DESCRIPTION:Title: Singular metrics of constant non-local curvature\nby Maria del Mar G
onzalez\, (Universidad Autónoma de Madrid) as part of Pangolin seminar\n\
n\nAbstract\nWe will consider the problem of constructing singular metrics
of constant non-local curvature in conformal geometry\, using a gluing sc
heme. This non-local curvature is defined from the conformal fractional La
placian\, a Paneitz type operator of non-integer order. For the gluing pro
cess\, one needs a model solution which is given by the solution of a non-
local ODE with good conformal properties. It turns out that conformal geom
etry provides powerful tools for the analysis of such equations.\n
LOCATION:https://researchseminars.org/talk/Geometry/27/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Melanie Rupflin (Oxford University)
DTSTART;VALUE=DATE-TIME:20210615T133000Z
DTEND;VALUE=DATE-TIME:20210615T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/28
DESCRIPTION:Title: Lojasiewicz inequalities near simple bubble trees\nby Melanie Rupfli
n (Oxford University) as part of Pangolin seminar\n\n\nAbstract\nIn the st
udy of (almost-)critical points of an energy functional one is often confr
onted with the problem that a weakly-obtained limiting object does not hav
e the same topology. For example sequences of almost-harmonic maps from a
surface will in general not converge to a single harmonic map but rather t
o a whole bubble tree of harmonic maps\, which cannot be viewed as an obje
ct defined on the original domain.\n\nOne of the consequences of this phen
omenon is that one of the most powerful tools in the study of (almost-)cri
tical points and gradient flows of analytic functionals\, so called Lojasi
ewicz-Simon inequalities\, no longer apply.\n\nIn this talk we discuss a m
ethod that allows us to prove such Lojasiewicz inequalities for the harmon
ic map energy near simple trees and explain how these inequalities allow u
s to prove convergence of solutions of the corresponding gradient flow des
pite them forming a singularity at infinity.\n
LOCATION:https://researchseminars.org/talk/Geometry/28/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Renato Vianna (Universidade Federal do Rio de Janeiro)
DTSTART;VALUE=DATE-TIME:20210629T133000Z
DTEND;VALUE=DATE-TIME:20210629T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/29
DESCRIPTION:by Renato Vianna (Universidade Federal do Rio de Janeiro) as p
art of Pangolin seminar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Geometry/29/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Misha Belolipetsky (IMPA\, Rio de Janeiro)
DTSTART;VALUE=DATE-TIME:20210713T133000Z
DTEND;VALUE=DATE-TIME:20210713T143000Z
DTSTAMP;VALUE=DATE-TIME:20210612T234510Z
UID:Geometry/30
DESCRIPTION:by Misha Belolipetsky (IMPA\, Rio de Janeiro) as part of Pango
lin seminar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Geometry/30/
END:VEVENT
END:VCALENDAR