# turkmath.org

Türkiye'deki Matematiksel Etkinlikler

 Seminer Dizisi 26 Temmuz 2021 - 23 Kasım 2021 Gökova Geometry Topology Institute - online Date: July 26-30, 2021 Speaker: Mahir Bilen Can (Tulane University) Title: Lie Groups and Algebraic Groups in Action Abstract: The purpose of our lectures is to give a short but self-contained overview of some well-known results about the geometry of algebraic group actions. We will focus mainly on the actions of connected reductive groups. Our main goals are 1) introducing some interesting examples of equivariant completions of homogeneous spaces, 2) explaining several combinatorial gadgets such as valuation cones, weight monoids, colors, etc. that are not only useful for classifying algebraic actions of low complexity but also essential for understanding these equivariant completions. Along the way, we will review some representation theory. In addition, we will analyze some concrete examples of combinatorial varieties such as toric and Schubert varieties. Lecture 1 Monday, July 26 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Lecture 2 Tuesday, July 27 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Lecture 3 Wednesday, July 28 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Lecture 4 Thursday, July 29 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Lecture 5 Friday, July 30 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) ----------------------------------- Date: August 23-26, 2021 Speakers: Joé Brendel (University of Neuchâtel) and Felix Schlenk (University of Neuchâtel) Title: Toric Symplectic Manifolds Abstract: Toric symplectic manifolds are symplectic manifolds with an effective Hamiltonian torus action of maximal dimension. Toric manifolds are distinguished by the property that they can be reconstructed from a combinatorial object called the moment polytope. Thus they are a great playground for symplectic topology and the study of Lagrangian submanifolds, since complicated invariants may be reduced to combinatorial properties of the corresponding moment polytope. In recent years, there has been much interest in a generalization called “almost toric” structures. In these four lectures, we will introduce these two classes of symplectic manifolds, and use their special structure to study Lagrangian tori and symplectic embedding problems. Lecture 1. Monday, August 23 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) The Delzant construction by Joé Brendel Lecture 2. Tuesday, August 24 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Versal deformations and the Chekanov torus by Joé Brendel Lecture 3. Wednesday, August 25 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Almost toric symplectic fibrations by Felix Schlenk Lecture 4. Thursday, August 26 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) Three applications (maximal embeddings of ellipsoids, exotic Lagrangian tori, and non-isotopic cube embeddings) by Felix Schlenk ----------------------------------- Date: September 27-28, 2021 Speakers: Selman Akbulut (GGTI) and Eylem Zeliha Yildiz (Duke University) Title: Shaking Knots Abstract: "Knot Shaking" is a technique introduced $44$ years ago as a tool to study exotic smoothings of $4$-manifolds with boundary. Let be $K$ be a knot, and  $K^{r}$ be the $4$-manifold obtained by attaching a $2$-handle to $B^{4}$ along $K$ with framing $r$. We say that $K$ is  $r$-shake slice if a generator of  $H_{2}(K^{r})=Z$ is represented by a smoothly imbedded $2$-sphere; this is equivalent to saying that the link consisting of $K$ and an even number of oppositely oriented parallel copies of $K$ (parallel with respect to $r$-framing) to bound disk with holes in $B^4$. Clearly slice knots are $r$-shake slice. It is known that when $r\neq 0$ not all $r$-shake slice knots are slice, and there are knots that are not $r$-shake slice. We address the important remaining case of $r=0$, and prove that $0$-shake slice knots are slice. Along the way, we discuss how shaking is related to the exotic smooth structures and corks. Lecture 1. Monday, September 27 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) by Eylem Zeliha Yildiz Lecture 2. Tuesday, September 28 at 6 AM (PT), 9 AM (EDT), 4 PM (TRT) by Selman Akbulut ----------------------------------- NOT: The lectures will take place online via Zoom. Geometri, Topoloji Etkinliğin Web Sayfası eylem.yildiz@duke.edu ggti 25.09.2021

## İLETİŞİM

Akademik biriminizin ya da çalışma grubunuzun ülkemizde gerçekleşen etkinliklerini, ilan etmek istediğiniz burs, ödül, akademik iş imkanlarını veya konuk ettiğiniz matematikçileri basit bir veri girişi ile kolayca turkmath.org sitesinde ücretsiz duyurabilirsiniz. Sisteme giriş yapmak için gerekli bilgileri almak ya da görüş ve önerilerinizi bildirmek için iletişime geçmekten çekinmeyiniz. Katkı verenler listesi için tıklayınız.

Özkan Değer ozkandeger@gmail.com

## DESTEK VERENLER

31. Journees Arithmetiques Konferansı Organizasyon Komitesi

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