{"id":2881,"date":"2012-10-26T13:32:24","date_gmt":"2012-10-26T13:32:24","guid":{"rendered":"http:\/\/math.columbia.edu\/~dejong\/wordpress\/?p=2881"},"modified":"2012-10-26T13:32:24","modified_gmt":"2012-10-26T13:32:24","slug":"quothilbert-schemes","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/?p=2881","title":{"rendered":"Quot\/Hilbert schemes"},"content":{"rendered":"<p>It is standard practice to construct the Hilbert scheme as a special case of the Quot scheme. Often you can construct the Quot scheme out of a Hilbert scheme too.<\/p>\n<p>Namely, suppose you have X &#8212;> S a flat, proper morphism of finite presentation and suppose that F is a finitely presented O_X-module. Then you can consider<\/p>\n<blockquote><p>Y = Spec(O_X[F]) &#8212;> X<\/p><\/blockquote>\n<p>where O_X[F] = O_X &oplus; F is the O_X-algebra where F is a square zero ideal. We have a section &sigma; : X &#8212;> Y. Then we can consider the closed subscheme Q of Hilb_{Y\/S} parametrizing families of closed subschemes of Y which contain &sigma;. If I am not mistaken, then Q = Quot_{F\/X\/S}.<\/p>\n<p>This only works because we assumed X &#8212;> S is proper and flat!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>It is standard practice to construct the Hilbert scheme as a special case of the Quot scheme. Often you can construct the Quot scheme out of a Hilbert scheme too. Namely, suppose you have X &#8212;> S a flat, proper &hellip; <a href=\"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/?p=2881\">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":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2881","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2881","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2881"}],"version-history":[{"count":7,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2881\/revisions"}],"predecessor-version":[{"id":2888,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2881\/revisions\/2888"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2881"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2881"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2881"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}