Geometry Main 14 15a 15b 18 19 20a 20b 20c 20d 20e

The 7th GTSS


Nesin Mathematics Village, Şirince, İzmir
September 7-20, 2020

(Invitation process is started. Let us know
if you have a research-mini-course proposal!)

First Week


TIME              SPEAKER                  TITLE
Sep 7-13
Stephen Huggett Special relativity from a mathematician’s point of view
Sep 7-13
Silvio Dolfi Character Theory of Finite Groups
Jul 6-12
Keti Tenenblat* Quasi-Einstein Metrics
Jul 6-12
Agustin Moreno* 3-manifolds, loop and sphere theorems
Aug 17-23
Damien Gayet
Topics in Calibrated Geometries*
Sep 9-15
Craig Van Coevering
Special Metrics in Sasakian Geometry A
Sep 9-13
Misha Verbitsky Hyperkähler Manifolds
Sep 9-14
Kotaro Kawai Calibrated submanifolds in G2 manifolds
Sep 9-15
Mehmet Kılıç Metric Geometry
Sep 9-15
Özgür Kelekçi Kähler Geometry A
Sep 9-15
Buket Can Bahadır Introduction to Several Complex Variables A
Sep 9-15
İlker Savaş Yüce Hyperbolic Geometry
Sep 9-15
Özgür İnce Algebraic Curves

Second Week


TIME              SPEAKER                  TITLE
Sep 14-20
Stephen Huggett Twistor Geometry
Aug 24-30
Andrei Moroianu Locally Conformally Kähler (lcK) Manifolds*
Aug 24-30
Akito Futaki Einstein-Maxwell Kähler metrics*
Aug 24-30
Lorenzo Foscolo Gibbons-Hawking Ansatz of Hyperkähler Metrics
in Dimension 4
Aug 24-30
Siddhartha Gadgil Geometric group theory and Hyperbolic Geometry
Sep 16-18
Craig Van Coevering Special Metrics in Sasakian Geometry B
Sep 16-20
Lei Ni Complex geometric analysis
Lecture Notes , Seminar
Sep 16-20
Yanyan Niu Differential Harnack estimate on manifolds
Sep 16-22
Murat Savaş Hyperbolic Geometry
Sep 16-18
Özgür Kelekçi
Kähler Geometry B
Sep 16-22
Buket Can Bahadır
Introduction to Several Complex Variables B
Jan 13-18
Çağrı Hacıyusufoğlu     Minimal Surfaces    
Jan 20-26
Mohan Bhupal Riemann Surfaces and Fuchsian Groups

Scientific Commitee


Vicente Cortés University of Hamburg, Germany
İzzet Coşkun University of Illinois at Chicago, USA
Marisa Fernández Universidad del País Vasco, Bilbao, Spain
Ljudmila Kamenova Stony Brook University, USA
Lei Ni University of California at San Diego, USA
Tommaso Pacini University of Torino, Italy
Gregory Sankaran University of Bath, UK
Misha Verbitsky IMPA, Brasil

Register-TR       Poster       Participants       Arrival


The 2nd GTSS will be held at the Nesin Mathematical Village in Şirince, İzmir.
There will be about 15 mini-courses of introductory nature, related to the Geometry-Topology research subjects.
In the middle of the week there is an excursion to the Ancient City of Ephesus and/or Kuşadası Beach.

Wifi info: Passwords are TermoS1! at the Library (Kutuphanegenel) networks, zeytinlik for istasyon and kurugolet for kisbahcesi at the registration lobby.


Graduate students, recent Ph.D.s and under-represented minorities are especially encouraged to the summer school.
Partial financial support is available. Daily expenses including bed, breakfast, lunch, dinner is around 20€.

Please fill out the application form to attend to the summer school.
Airport: İzmir Adnan Menderes Airport - ADB is the closest one.
For pick up, faculty is advised to get out of the terminal building from the domestic gate and wait there.
Also let us know before hand, your whatsapp number and/or Google-Hangouts address in case of a problem.
Small amounts of Turkish Lira may be needed in the village
which you can withdraw from ATM machines at the airport or tell the driver along the way.
In case you are coming to the Village independently, from the Airport you may take the regional trains to Selçuk,
possibly with a break at Tepeköy. Then from Selçuk take a taxi which costs about 10€.
Taxi Drivers: +90 232 892 3125 (Gar Taxi), +90 553 243 0835 (Volkan), +90 532 603 1518 (Ata).
Visas: Check whether you need a visa beforehand.

Simply Easy Learning


Special relativity from a mathematician’s point of view

This will be a gentle introduction to special relativity, from the mathematician’s point of view. So we shall understand special relativity as a geometry, that is, as a mathematical space together with a group of transformations acting on that space.

1. Principles of special relativity

2. The Lorentz group

3. Effects in space and time

4. The metric, and causality

5. Aberration

6. The celestial sphere, and SL(2,C)

Prerequisites: Groups of transformations, elementary linear algebra, elementary geometry.

Level: Advanced undergraduate

Twistor Geometry

This will be a gentle introduction to twistor geometry. We will describe the Klein correspondence between Minkowski space and twistor space, and we will give an elementary account of the Penrose transform.

1. Compactification of Minkowski space

2. Definition of Twistor space

3. The Klein correspondence

4. Causal structure

5. Real points

6. Functions on Twistor space

7. A double fibration

Prerequisites: Special relativity, complex analysis, projective geometry

Level: Graduate

Character Theory of Finite Groups

Foundation of the theory of linear representations and characters of finite groups. Basic tools: induction and restriction, Clifford theory. Applications to group theory: theorems of Burnside and Frobenius. Character degrees and groups structure: theorems of Ito and Thompson.

Textbook: I.M. Isaacs, Character Theory of Finite Groups

Prerequisites: Some finite group theory and linear algebra.

Level: Advanced undergraduate

Einstein-Maxwell Kähler metrics(*)

Locally Conformally Kähler (lcK) Manifolds(*)

Special metrics in Sasakian geometry

This course will begin with an introduction to Sasakian geometry, a type of metric contact structure which is an odd dimensional analogue of a Kähler structure on a complex manifold. We will then consider the problem of finding a special Sasakian metrics, such as Einstein, and more generally constant scalar curvature and extremal metrics.

Textbook or/and course webpage:

1. Boyer, Charles P.; Galicki, Krzysztof. Sasakian geometry. Oxford Mathematical Monographs. Oxford University Press, Oxford, 2008. xii+613 pp.

2. Futaki, Akito; Ono, Hajime; Wang, Guofang Transverse Kähler geometry of Sasaki manifolds and toric Sasaki-Einstein manifolds. J. Differential Geom. 83 (2009), no. 3, 585–635.

3. Collins, Tristan C.; Székelyhidi, Gábor. K-semistability for irregular Sasakian manifolds. J. Differential Geom. 109 (2018), no. 1, 81–109.


A first year graduated course in differential geometry should be sufficient.

Calibrated submanifolds in G2 manifolds

In this lecture, we first give a survey of calibrated submanifolds in G2 manifolds. Then we present their deformation theories.

Textbook or/and course webpage:

1. K. Kawai, Deformations of homogeneous associative submanifolds in nearly parallel G2-manifolds, Asian J. Math. 21 (2017), 429-462.

2. K. Kawai, Second-order deformations of associative submanifolds in nearly parallel G2-manifolds, Q. J. Math. 69 (2018), 241-270.

3. J. D. Lotay, Associative Submanifolds of the 7-Sphere, Proc. Lond. Math. Soc. (3) 105 (2012), 1183-1214.

4. R. C. McLean, Deformations of Calibrated Submanifolds, Comm. Anal.Geom. 6 (1998), 705-747.


Linear Algebra, Riemannian Geometry

Kähler Geometry

Kähler geometry has been an important area of differential geometry and attracted significant interest from both mathematics and mathematical physics research community. In this lecture series our aim is to provide an introduction to different aspects of Kähler geometry. We will start with a review of Riemannian geometry. Then emphasis will be on complex and Hermitian geometry which form the basis for Kähler manifolds. We will study several aspects of Kähler manifolds such as the Calabi-Yau theorem, Weitzenböck techniques, Calabi–Yau manifolds.

Textbook or/and course webpage:

A. Moroianu, “Lectures on Kähler Geometry”


Basic Differential Geometry (not a must but preferable)

Complex geometric analysis

I shall give a quick course on the complex/Kaehler geometry with emphasis of PDE methods.

Textbook or/and course webpage:

I shall distribute some notes. The students can start with books such as

Complex Manifolds, by J. Morrow and K. Kodaira, AMS.

Principles of of Algebraic Geometry, by Griffiths-Harris, John Wiley and Sons.

Differential Analysis on Complex Manifolds, by Wells. Springer.

Complex differential manifolds, by Zheng, AMS/IP.

Complex geometry, by Huybrechts, Springer.


Linear Algebra, Partial Differential Equations/Complex Analysis (not a must but preferable)

Differential Harnack estimate on manifolds

In this lecture series we present “Li-Yau-Hamilton“ type differential Harnack estimate on Riemannian manifolds and Kähler manifolds.

Textbook or/and course webpage:

1. Bennett Chow, Peng Lu and Lei Ni, Hamilton’s Ricci flow, Graduate Studies in Mathematics, 77. American Mathematical Society, Providence, RI; Science Press Beijing, New York, 2006.

2. B.Wilking, A Lie algebraic approach to Ricci flow invariant curvature condition and Harnack inequalities, J. reine angew. Math. (Crelle), 679 (2013), 223–247.

3. L. Ni and Y. Y. Niu, Sharp differential estimates of Li-Yau-Hamilton type for positive (p, p)-forms on Kähler manifolds. Comm. Pure Appl. Math., 64 (2011), 920–974.


Riemannian manifold, Kähler manifold (not a must but preferable)

Spin-c structures on manifolds and geometric applications

These lecture series aim to give an elementary exposition on basic results about the first eigenvalue of the Dirac operator, on compact Riemannian Spin and Spin^c manifolds and their hypersurfaces. For this, we select some key ingredients which illustrate the basic objects and some of their properties as Clifford algebras, spin and spin^c groups, connections, covariant derivatives, Dirac and Twistor operators. We end by giving beautiful geometric applications: a Lawson type correspondence for constant mean curvature surfaces in some 3-dimensional Thurston geometries, extrinsic hyperspheres in manifolds with special holonomy, Alexandrov type theorems…

Textbook or/and course webpage:

1. Th. Friedrich, Dirac operator’s in Riemannian Geometry, Graduate studies in mathematics, Volume 25, American Mathematical Society, 2000

2. H.B. Lawson and M.L. Michelson, Spin Geometry, Princeton University press, Princeton, New Jersey, 1989.

3. J.P. Bourguignon, O. Hijazi, J.L. Milhorat, A. Moroianu and S. Moroianu, A Spinorial Approach to Riemannian and Conformal Geometry, Monographs in Mathematics, European Mathematical Society (June 2015) 462 pages.


Linear Algebra, Riemannian Geometry

Partial Differential Equations (Sobolev and Hölder Spaces)

Partial Differential Equations, Functional Analysis, Riemannian Geometry (not a must but preferable).

Level: Graduate, advanced undergraduate

Abstract: In this lecture series, our aim is to introduce Sobolev Spaces, and to present techniques and ideas from functional analysis to develop the theory. Since the solutions of partial differential equations are naturally found in Sobolev spaces, this theory proves to be a useful tool for several applications in partial differential equations, as well as giving us an opportunity for a different aproach to classical problems using the methods of functional analysis. We also would like to make an introduction to how these concepts can be aplied in the set up of Riemannian Manifolds., and give examples, such as Yamabe problem, where this aprooach played an important role.

Textbook or/and course webpage:

Evans, Lawrence C. - Partial differential equations. Second edition. Graduate Studies in Mathematics, 19. American Mathematical Society, Providence, RI, 2010.

Metric Geometry

Prerequisites: Temel Analiz bilgisi ve metrik uzaylara aşinalık.

Level: Graduate, advanced undergraduate

Abstract: Bu derste, uzunluk uzayları ve jeodezik uzaylar tanıtılacaktır. Ascoli Teorem'i ifade ve ispat edilecek ve bunun sonucu olarak bir ''proper'' metrik uzayda, sonlu uzunluğa sahip bir yolla birleştirilebilen iki nokta arasında, minimal uzunluğa sahip bir yolun var olduğu gösterilecektir. Daha sonra metrik uzaylarda bazı konvekslik kavramları incelenecektir. Language: TR

Textbook: Metric Spaces, Convexity and Nonpositive Curvature; Athanase Papadopoulos. A Course in Metric Geometry; Dmitri Burago, Yuri Burago, Sergei Ivanov.

Hyperbolic Geometry

In this lecture series we give an introduction to hyperbolic geometry with some discussion of other non-Euclidean systems. We generate useful volume and area formulas for tetrahedrons and triangles in low-dimensional hyperbolic space. Daily sections of the lecture are given below.

Description of the hyperbolic geometry models and the connection between them. Description of the general Mobius group. Characterization of the isometries of hyperbolic space. Geometry of hyperbolic triangles. Hyperbolic trigonometry. Hyperbolic area and the Gauss-Bonnet theorem.

Textbook or/and course webpage:

1. Anderson, James W. – Hyperbolic Geometry, Springer-Verlag, London, 2005.

2. Ratcliffe, John G., Foundations of Hyperbolic Manifolds, Graduate texts in Mathematics, 149, Springer, New York, 2006.


Linear Algebra

Generalization of Einstein metrics

In this lecture series we review some generalizations of Einstein metrics. These are Ricci solitons, static spaces and warped-product Eınstein metrics. As a tool to approach these strucures, we start with some study on the so-called Codazzi tensors and then talk about harmonic curvature and harmonic Weyl curvature. After these, we apply the Codazzi tensor approach to study each of the above generalizations of Einstein metrics.

Textbook or/and course webpage:

1. A.L. Besse - Einstein manifolds, Chapter 16, Ergebnisse der Mathematik, 3 Folge, Band 10, Springer-Verlag, 1987.

2. G. Catino, C. Mantegazza, L. Mazzieri, A note on Codazzi tensors, Math. Ann. 362 (2015), No. 1-2, 629-638.

3. J. Kim. On a classification of 4-d gradient Ricci solitons with harmonic Weyl curvature, J. Geom. Anal. 27, (2017), no. 2, 986-1012.


Riemannian Geometry

Hyperkähler Manifolds

Hyperkähler manifolds are manifolds with 3 complex structures satisfying quaternionic relations, and a torsion-free orthogonal connection preserving these complex structures. A number of objects arising in hyperkähler geometry are equipped with hyperkähler structure, such as moduli of vector bundles, deformation spaces, subvarieties and so on. This allows one to speak of “hyperkähler geometry”, similar to the usual complex algebraic geometry. I would explain basic properties of hyperkähler manifolds, give some examples and prove results about subvarieties.

Textbook or/and course webpage:

Besse, “Einstein manifolds”


Differential geometry, topology

Kalafat: We show that a compact complex surface which admits a conformally Kahler metric g of positive orthogonal holomorphic bisectional curvature is biholomorphic to the complex projective plane. In addition, if g is a Hermitian metric which is Einstein, then the biholomorphism can be chosen to be an isometry via which g becomes a multiple of the Fubini-Study metric. This is a joint work with C.Koca.


Kalafat, Mustafa; Koca, Caner -
Conformally Kähler surfaces and orthogonal holomorphic bisectional curvature. Geom. Dedicata 174 (2015), 401–408.

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