{"id":5548,"date":"2013-02-07T14:34:53","date_gmt":"2013-02-07T19:34:53","guid":{"rendered":"http:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=5548"},"modified":"2013-02-07T14:36:54","modified_gmt":"2013-02-07T19:36:54","slug":"existence-of-khler-einstein-metrics","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=5548","title":{"rendered":"Existence of K&auml;hler-Einstein Metrics"},"content":{"rendered":"<p>An important recent development in geometry has been the announcement of two claimed proofs of a long-standing conjecture about the existence of K&auml;hler-Einstein metrics.  Simon Donaldson is talking about this at MIT this week (see <a href=\"http:\/\/events.mit.edu\/scripts\/event_ext.pl?event=14992736&#038;location=http:\/\/www-math.mit.edu\/news\/&#038;groupid=2861\">here<\/a> and <a href=\"http:\/\/events.mit.edu\/scripts\/event_ext.pl?event=14992737&#038;location=http:\/\/www-math.mit.edu\/news\/&#038;groupid=2861\">here<\/a>), and the last in a series of his papers with Xiuxiong Chen and Song Sun giving details of their proof appeared on the arXiv earlier this week, see <a href=\"http:\/\/arxiv.org\/abs\/1302.0282\">here<\/a>.   For the earlier papers in the series, see <a href=\"http:\/\/arxiv.org\/abs\/1212.4714\">here<\/a> and <a href=\"http:\/\/arxiv.org\/abs\/1211.4566\">here<\/a>, as well as the original announcement of the proof in outline <a href=\"http:\/\/arxiv.org\/abs\/1210.7494\">here<\/a>. Gang Tian also has a preprint with a proof, see <a href=\"http:\/\/arxiv.org\/abs\/1211.4669\">here<\/a>.   As usual in mathematics, one might want to wait for these preprints to be refereed by experts before being sure that a proof is in hand.<\/p>\n<p>Given any manifold, there&#8217;s an infinity of ways of putting a metric on it.  A major theme in modern geometry and topology has been the pursuit of the idea that in many cases there may be a unique &#8220;best&#8221; choice for such a metric.  The proof of the Poincar&eacute; Conjecture involved just this sort of idea, showing that starting with any metric on a simply-connected three-manifold one could deform it in a specific way to end up with certain special possibilities that could be completely analyzed.   <\/p>\n<p>For K&auml;hler manifolds, the big open question of this kind has been that of whether one can find a unique metric that is both K&auml;hler and Einstein (thus &#8220;K&auml;hler-Einstein&#8221;).  For negative first Chern class this was shown by Aubin and Yau, and for zero first Chern class by Yau in his proof of the Calabi conjecture (these are the &#8220;Calabi-Yau&#8221; manifolds).   For positive Chern class there are counter-examples, but the conjecture has long been that K&auml;hler manifolds satisfying an appropriate notion of &#8220;stability&#8221; will have such a unique K&auml;hler-Einstein metric, and it is this conjecture that apparently has now been proven.<\/p>\n<p>The details of this are far beyond my expertise, so I refer you to the papers quoted above, as well as some expository articles about the problem by <a href=\"http:\/\/www2.imperial.ac.uk\/~skdona\/CLAY.PDF\">Donaldson<\/a> and <a href=\"http:\/\/smp.uq.edu.au\/sites\/smp.uq.edu.au\/files\/proc-for-cheeger.pdf\">Tian<\/a>, as well as a series of blog posts (<a href=\"http:\/\/terrytao.wordpress.com\/2007\/05\/15\/distinguished-lecture-series-i-shing-tung-yau-what-is-a-geometric-structure\/\">here<\/a>, <a href=\"http:\/\/terrytao.wordpress.com\/2007\/05\/17\/distinguished-lecture-series-ii-shing-tung-yau-the-basic-tools-to-construct-geometric-structures\/\">here<\/a>, and <a href=\"http:\/\/terrytao.wordpress.com\/2007\/05\/18\/distinguished-lecture-series-iii-shing-tung-yau-application-of-the-geometric-structures-to-solve-problems-in-algebraic-geometry-and-topology\/\">here<\/a>) by Terry Tao based on lectures by Yau.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>An important recent development in geometry has been the announcement of two claimed proofs of a long-standing conjecture about the existence of K&auml;hler-Einstein metrics. Simon Donaldson is talking about this at MIT this week (see here and here), and the &hellip; <a href=\"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/?p=5548\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[1],"tags":[],"class_list":["post-5548","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/5548","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=5548"}],"version-history":[{"count":7,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/5548\/revisions"}],"predecessor-version":[{"id":5554,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/5548\/revisions\/5554"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=5548"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=5548"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~woit\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=5548"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}