{"id":2603,"date":"2023-05-09T11:57:49","date_gmt":"2023-05-09T08:57:49","guid":{"rendered":"https:\/\/mathematics.haifa.ac.il\/?p=2603"},"modified":"2023-06-06T15:22:35","modified_gmt":"2023-06-06T12:22:35","slug":"colloquium-tuesday-may-16-2023-speaker-assaf-hasson-bgu-title-how-hard-is-it-for-a-variety-to-forget-who-it-is","status":"publish","type":"post","link":"https:\/\/mathematics.haifa.ac.il\/?p=2603","title":{"rendered":"Colloquium: Tuesday May 16, 2023. Speaker: Assaf Hasson (BGU). Title: &#8220;How hard is it for a variety to forget who it is?&#8221;."},"content":{"rendered":"\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Our next Math&nbsp;colloquium&nbsp;this term&nbsp;will be&nbsp;<strong>in person<\/strong>&nbsp;on Tuesday the 16th of May, in room 614, Science &amp; Education building.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A zoom link for our meetings is:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/us02web.zoom.us\/j\/83337601824\">https:\/\/us02web.zoom.us\/j\/83337601824<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Speaker :&nbsp;<strong>Assaf Hasson (BGU)<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Date :&nbsp;<strong>Tuesday, 16th of May, 2023.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Time :&nbsp;<strong>14:00<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Title:<\/strong>&nbsp;How hard is it for a variety to forget who it is?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Abstract:&nbsp;<\/strong>Consider an algebraic variety V over an algebraically closed field K (or, more generally, a finite Boolean combination of affine varieties over K). Consider V with its full Zariski structure. I.e., for all n we equip V^n with all the Zariski closed subsets of V^n defined over K. With a little work, it follows from a celebrated theorem of Hrushovksi and Zilber that in this structure a copy, K&#8217;,&nbsp; of K is definable, that V can be identified with an algebraic variety over K&#8217;, and that the Zariski structure of Z over K&#8217; is the same as the one over K we started with. We address the following question: suppose we start with V as above, but equip it with only part of its Zariski structure (e.g., if V is a curve, retain only one 3-dimensional Zariski closed subset of V^4). Under what conditions no information is actually lost, i.e., we can still recover every definable subset of V^n (all n) as a constructible set over some definable algebraically closed field K&#8217;.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In the talk I will present the notion of very ample strongly minimal sets, and explain how &#8212; using the recent solution of Zilber&#8217;s &#8220;restricted trichotomy conjecture&#8221; for algebraically closed fields &#8212; allows us to give a complete (abstract) answer the above question.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">*Joint work with Ben Castle<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Our next Math&nbsp;colloquium&nbsp;this term&nbsp;will be&nbsp;in person&nbsp;on Tuesday the 16th of May, in room 614, Science &amp; Education building. A zoom link for our meetings is: https:\/\/us02web.zoom.us\/j\/83337601824 Speaker :&nbsp;Assaf Hasson (BGU) Date :&nbsp;Tuesday, 16th of May, 2023. Time :&nbsp;14:00 Title:&nbsp;How hard&#8230;<br \/><a class=\"read-more-button\" href=\"https:\/\/mathematics.haifa.ac.il\/?p=2603\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[],"class_list":["post-2603","post","type-post","status-publish","format-standard","hentry","category-colloquium"],"_links":{"self":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts\/2603","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2603"}],"version-history":[{"count":1,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts\/2603\/revisions"}],"predecessor-version":[{"id":2604,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=\/wp\/v2\/posts\/2603\/revisions\/2604"}],"wp:attachment":[{"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2603"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2603"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mathematics.haifa.ac.il\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2603"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}