Seminar on Geometry

Spring/Fall 2023, Boğaziçi, İstanbul

Time / Location: Fridays 4:00 / TB-240

Schedule of talks

 

TIME              SPEAKER                  TITLE
Jan 16-21

The 10th GTSS Geometry-Topology Winter School
Nesin Mathematics Village
Jan 27
Fri, 4:00
No Seminar
Feb 3
Fri, 4:00
Zoom link. Pass: geometry in Turkish.
Meeting ID: 991 1027 7750
Spectrum of the Riemannian Laplacian on the round n-dimensional sphere
Feb 10
Fri, 4:00
Spectrum of the Riemannian Laplacian on the round n-dimensional sphere 2
Feb 17
Fri, 4:00

Minimal Surfaces and the Bernstein Problem 1
Index of Spheres as totally geodesic minimal submanifolds
Feb 24
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 2
Jacobi Fields on Spheres
Mar
4-5
Conference SCGAS
Irvine, CA
Mar 10
Fri, 4:00
No Seminar
Mar 17
Fri, 4:00

Minimal Surfaces and the Bernstein Problem 3
Negative definite index form
Mar 24
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 4
Killing fields on the sphere
Mar 31
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 5
Using Killing fields on the sphere to find nullity
Apr 7
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 6
An extrinsic rigidity theorem
Apr 13
Thu, 4:30
Jan Kotrbaty
Frankfurt
An algebraic approach to inequalities in convex geometry
Oberseminar Differentialgeometrie, MPIM Lecture Hall
Apr 14
Fri, 3:30
Craig van Coevering
Boğaziçi
Extremal Kähler metrics and the moment map
Online AG Seminar
Apr 20
Thu, 4:30
Tommaso Cremaschi
Luxembourg
Geometry of some infinite-type hyperbolic 3-manifolds
Oberseminar Differentialgeometrie, MPIM Lecture Hall
Apr 21
Fri, 4:00
Holiday
Ramazan Bayramı
Apr 25
Tue, 4:30
Thomas Schick
Göttingen
Rigidity of scalar curvature and low regularity
Oberseminar Topologie, Endenicher Allee 60, Raum 1.008
Apr 28
Fri, 3:00
Minimal Surfaces and the Bernstein Problem 7
Rigidity theorem for higher codimension
May 4
Thu, 10:30
Justin Sawon
North Carolina/MPIM
Lagrangian fibrations in six dimensions
Seminar Algebraic Geometry (SAG) Vivatsgasse 7, Hörsaal MPIM

4:30
Shi Wang
MSU/MPIM
Eisenstein series and cusp counting in hyperbolic manifolds
Oberseminar Differentialgeometrie, MPIM Lecture Hall
May 5
Fri, 3:00
Minimal Surfaces and the Bernstein Problem 8
Rigidity theorem for higher codimension 2
May
8-12
Workshop Noncommutative Geometry and Operator Algebras
Lecture hall HIM, Poppelsdorfer Allee 45, Bonn
May 11
Thu, 4:30
Thang Nguyen
Uni. of Michigan
Local rigidity of boundary actions
Oberseminar Differentialgeometrie, MPIM Lecture Hall
May 12
Fri, 3:00
Minimal Surfaces and the Bernstein Problem 9
Sphere rigidity theorem
May
17-19
Conference A Complex Differential Geometry Meeting at UniTo
Università degli Studi di Torino
May 24
Wed, 2:00
Dies Academicus
May 26
Fri, 4:00
No Seminar
Jun 2
Fri, 4:00
Holiday
Pfingstferien
Jun 9
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 10
TBA
Jun 16
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 11
Index and nullity of a minimal surface
Jun 23
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 12
TBA
Jun 30
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 13
Minimal surfaces in the 6-sphere. First and second normal bundles
Jul 7
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 14
Moving frames in the 6-sphere
Jul 14
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 15
TBA
Jul 17-22
Youtube The 11th GTSS Geometry-Topology Summer School
IMBM - Week 1
Jul 24-29
Videos Summer School
IMBM - Week 2
Aug 4
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 16
Holomorphic curvature and torsion
Aug
7-11
Conference Analytic Methods in Complex Geometry
Münster
Aug 18
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 18
Holomorphic interpretation of the Torsion
Aug 25
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 19
Holomorphic Frenet equations
Sep 1
Fri, 4:00
Minimal Surfaces and the Bernstein Problem 20
Holomorphic interpretation of the Torsion
Sep 8
Fri, 4:00
No Seminar
Sep 11-16

The 12th GTSS Geometry-Topology Summer School
Nesin Mathematics Village - Week 1
Sep 18-23

Summer School
Week 2
Sep 29
Fri, 3:30
No Seminar
Oct 7
Fri, 3:30
Minimal varieties in higher dimensional spheres 1
Introduction. Riemannian vector bundles.
Oct
13-16
Conference Symmetry and shape
Santiago de Compostela, Spain
Oct 21
Fri, 3:30
Minimal varieties in higher dimensional spheres 2
Laplace operator
Oct 28
Fri, 3:30
Minimal varieties in higher dimensional spheres 3
Geometry of immersed submanifolds
Nov 4
Fri, 3:30
Minimal varieties in higher dimensional spheres 4
Curvature of the normal bundle
Nov 8
Tue, 2:15
Oberseminar
Global Analysis and Operator Algebras
On special submanifolds of the Page space
Location: Endenicher Allee 60, Room 0.008
Nov 11
Fri, 3:30
Minimal varieties in higher dimensional spheres 5
Mean curvature and minimal varieties
Nov 18
Fri, 4:00
Minimal varieties in higher dimensional spheres 6
The case of Kähler manifolds
Nov 25
Fri, 4:00
Minimal varieties in higher dimensional spheres 7
The case of Kähler manifolds 2
Dec 2
Fri, 4:00
Minimal varieties in higher dimensional spheres 8
The case of Kähler manifolds 3
Dec 9
Fri, 4:00
Minimal varieties in higher dimensional spheres 9
An extension of the Synge Lemma
Dec 16
Fri, 4:00
Minimal varieties in higher dimensional spheres 10
Laplacian of the Shape Operator
Dec 23
Fri, 4:00
Minimal varieties in higher dimensional spheres 11
Mean curvature and minimal varieties
Dec 30
Fri, 4:00
Minimal varieties in higher dimensional spheres 12
Curvature of the normal bundle
Jan 6
Fri, 4:00
Minimal varieties in higher dimensional spheres 13
Projection of parallel vector fields as the Kernel of the Jacobi operator

Abstracts/Notlar


Spectrum of the Riemannian Laplacian on the round n-dimensional sphere


Using the spherical harmonic functions we understand the eigenvalues and eigenvectors of the Laplacian on the round 2-sphere also the general n-sphere. [1] contains explicit descriptions of the eigenvalues and eigenvectors of the standard basic manifolds including the n-sphere. Of historical interest is the treatment in what is arguably the first textbook on physics by Tait and Thomson. The latter (a.k.a. Lord Kelvin) used it to estimate the age of the sun. Inaccurately, but not due to errors in the mathematics, thermonuclear reactions hadn’t yet been discovered.[MO] We will be using the following resources.

References:

  1. Berger, Marcel; Gauduchon, Paul; Mazet, Edmond. - Le spectre d'une variété riemannienne.
    Lecture Notes in Mathematics, Vol. 194 Springer-Verlag, Berlin-New York 1971 vii+251 pp.

  2. Piotr Hajlasz – Functional Analysis notes.




Minimal Surfaces and the Bernstein Problem


In this learning seminar series, we will give an introduction to minimal submanifolds of the higher dimensional spheres. In particular we give estimates on the index of the Jacobi operator. Talk about applications on the Plateau's problem and Bernstein conjecture.

Ingredients of the individual seminars are as follows:

B-1: Index of Spheres as totally geodesic minimal submanifolds.

B-2: Jacobi fields on totally geodesic minimal spheres in higher dimensional spheres.

B-3: Negative definite index form.

B-4: Killing Fields on the sphere.

B-5: Using Killing Fields on the sphere to find nullity.

B-6: An extrinsic rigidity theorem.

B-7: Rigidity theorem for higher codimension.

B-8: Rigidity theorem for higher codimension 2.

B-9: Sphere rigidity theorem.

S-10: Laplacian of the Shape Operator.

S-11: Mean curvature and minimal varieties.

S-12: Curvature of the normal bundle.

S-13: Projection of parallel vector fields as the Kernel of the Jacobi operator.

We will be following the classical beautiful paper.

References:
  1. James Simons. - Minimal varieties in riemannian manifolds.
    Ann. of Math. (2), 88:62–105, 1968.




Seminars

Craig : An extremal Kähler metric is a canonical Kähler metric, introduced by E. Calabi, which is somewhat more general than a constant scalar curvature Kähler metric. The existence of such a metric is an ongoing research subject and expected to be equivalent to some form of geometric stability of the underlying polarized complex manifold (M,J,[ω]) –the Yau-Tian-Donaldson conjecture. Thus it is no surprise that there is a moment map, the scalar curvature (A. Fujiki, S. Donaldson), and the problem can be described as an infinite dimensional version of the familiar finite dimensional G.I.T.

I will describe how the moment map can be used to describe the local space of extremal metrics on a symplectic manifold. Essentially, the local picture can be reduced to finite dimensional G.I.T. In particular, we can construct a course moduli space of extremal Kähler metrics with a fixed polarization [ω]∈H2(M,ℝ) , which is an Hausdorff complex analytic space



Differential Geometry Seminar Archive


This page is maintained by  Mustafa Kalafat
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Activities are supported by University of Bonn and Boğaziçi University