<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">皆様，<br class=""><br class="">下記の要領で東工大幾何セミナーをZoom上で開催しますのでお知らせいたします．<br class=""><br class="">********************************************<br class=""><br class="">講演者：Nicholas Lindsay 氏（ShanghaiTech University）<br class=""><br class="">日時：7月17日（金）16:30〜18:00<br class=""><br class="">タイトル：Hamiltonian group actions and non-Kahler symplectic structures.<br class=""><br class="">要約：There are many examples of symplectic manifolds which cannot have a Kahler structure. However, in the presence of a Hamiltonian torus action, such examples are more scarce. For example Delzant proved that if there is a Hamiltonian action of a half dimensional torus then the symplectic manifold is necessarily Kahler. Also, Karshon proved that the existence of a Hamiltonian circle action on a closed symplectic 4-manifold, implies the manifold is Kahler. For a long time, it was unknown whether a closed symplectic manifold with a Hamiltonian torus action with finite fixed point set has an invariant Kahler metric. Then, Tolman constructed a closed symplectic 6-manifold with a Hamiltonian T^2-action with 6 fixed points not having a T^2-invariant Kahler metric.<br class=""> <br class="">Recently, Goertsches, Konstantis and Zoller shows that Tolmans manifold is diffeomorphic to a projective bundle over CP^2, hence has some Kahler metric. I will discuss a joint work with Dmitri Panov, in which we showed that the symplectic form constructed by Tolman has no compatible Kahler metric. The settles the problem of finding a compact symplectic manifold with a Hamiltonian circle action with finite fixed point set not having a compatible Kahler metric.<br class=""><br class="">********************************************<br class=""><br class="">Googleフォーム <a href="https://forms.gle/f1ZfmdE3EXy4Jd4y5" class="">https://forms.gle/f1ZfmdE3EXy4Jd4y5</a> にて参加登録を行います．<div class="">参加を希望される方は，7月16日（木）までに登録をお願いいたします．<br class="">セミナー当日に，登録いただいたメールアドレスにセミナーのZoom URLを送付いたします．<br class=""><br class="">今後のセミナーの予定については以下をご覧ください．<br class=""><a href="http://www.math.titech.ac.jp/page_05.html" class="">http://www.math.titech.ac.jp/page_05.html</a></div><div class=""><br class="">皆様のご参加をお待ちしております．<br class="">どうぞよろしくお願いいたします．<br class=""><br class="">橋本義規<br class="">東京工業大学理学院数学系</div><div class=""><br class=""></div><div class=""><br class=""><div class="">
<span class="im" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none; color: rgb(80, 0, 80);"><div dir="auto" style="overflow-wrap: break-word;" class=""><div dir="auto" style="color: rgb(0, 0, 0); overflow-wrap: break-word;" class=""><span style="color: rgb(153, 153, 153); font-family: arial, sans-serif; font-size: 12.7273px; background-color: rgb(255, 255, 255);" class="">Yoshinori Hashimoto</span></div><div dir="auto" style="overflow-wrap: break-word;" class=""><span style="background-color: rgb(255, 255, 255);" class=""><font color="#999999" face="arial, sans-serif" class=""><span style="font-size: 12.7273px;" class="">Department of Mathematics<br class="">Tokyo Institute of Technology<br class="">2-12-1 Ookayama, Meguro-ku,<br class="">Tokyo 152-8551<br class="">JAPAN</span></font></span></div></div></span><div style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div class="adm" style="margin: 5px 0px; color: rgb(34, 34, 34); font-family: Arial, Helvetica, sans-serif; font-size: small; font-variant-ligatures: normal; orphans: 2; widows: 2; background-color: rgb(255, 255, 255);"></div><div class="im" style="color: rgb(80, 0, 80); font-family: Arial, Helvetica, sans-serif; font-size: small; font-variant-ligatures: normal; orphans: 2; widows: 2; background-color: rgb(255, 255, 255);"></div></div>
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