{"id":3265,"date":"2013-06-28T02:44:38","date_gmt":"2013-06-28T02:44:38","guid":{"rendered":"http:\/\/math.columbia.edu\/~dejong\/wordpress\/?p=3265"},"modified":"2013-06-28T02:53:28","modified_gmt":"2013-06-28T02:53:28","slug":"update-22","status":"publish","type":"post","link":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/?p=3265","title":{"rendered":"Update"},"content":{"rendered":"<p>Since the last <a href=\"http:\/\/math.columbia.edu\/~dejong\/wordpress\/?p=2562\">update<\/a> we have added the following material:<\/p>\n<ol>\n<li>universal property of blowing up (schemes) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0806\">Tag 0806<\/a><\/li>\n<li>admissible blowups (schemes) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/080J\">Tag 080J<\/a><\/li>\n<li>strict transform (schemes) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/080C\">Tag 080C<\/a><\/li>\n<li>a section on fitting ideals (algebra) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/07Z6\">Tag 07Z6<\/a><\/li>\n<li>flattening by blowing up (schemes) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/080X\">Tag 080X<\/a><\/li>\n<li>proper modifications can be dominated by blowups (schemes) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/081T\">Tag 081T<\/a><\/li>\n<li>relative spectrum (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/03WD\">Tag 03WD<\/a><\/li>\n<li>scheme theoretic closure (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0831\">Tag 0831<\/a><\/li>\n<li>effective Cartier divisors (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/083A\">Tag 083A<\/a><\/li>\n<li>relative Proj (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0848\">Tag 0848<\/a><\/li>\n<li>blowing up (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/085P\">Tag 085P<\/a><\/li>\n<li>strict transforms (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0861\">Tag 0861<\/a><\/li>\n<li>admissible blowups (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/086A\">Tag 086A<\/a><\/li>\n<li>generalities on limits (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/07SB\">Tag 07SB<\/a><\/li>\n<li>flattening by blowups (spaces) <a href=\"http:\/\/stacks.math.columbia.edu\/tag\/087A\">Tag 087A<\/a><\/li>\n<li>David Rydh&#8217;s result that a decent space has a dense\u00a0open subscheme\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/086U\">Tag 086U<\/a><\/li>\n<li>QCoh is Grothendieck (spaces and stacks)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/077V\">Tag 077V<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0781\">Tag 0781<\/a><\/li>\n<li>proper modifications can be dominated by blowups (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/087G\">Tag 087G<\/a><\/li>\n<li>multiple versions of Chow&#8217;s lemma (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/089J\">Tag 089J<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/088U\">Tag 088U<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/089L\">Tag 089L<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/089M\">Tag 089M<\/a><\/li>\n<li>David Rydh&#8217;s result that a locally separated\u00a0algebraic space is decent\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/088J\">Tag 088J<\/a><\/li>\n<li>Grothendieck existence theorem (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/087V\">Tag 087V<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0886\">Tag 0886<\/a><\/li>\n<li>Grothendieck algebraization theorem (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/089A\">Tag 089A<\/a><\/li>\n<li>proper pushforward preserves coherence (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08AP\">Tag 08AP<\/a><\/li>\n<li>theorem on formal functions (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08AU\">Tag 08AU<\/a><\/li>\n<li>Grothendieck existence theorem (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08BE\">Tag 08BE<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08BF\">Tag 08BF<\/a><\/li>\n<li>a little bit about m-regularity\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08A2\">Tag 08A2<\/a><\/li>\n<li>connected spaces are nonempty (thanks to Burt)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/004S\">Tag 004S<\/a><\/li>\n<li>decent group space over field is separated\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08BH\">Tag 08BH<\/a><\/li>\n<li>derived Mayer-Vietoris (ringed spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08BR\">Tag 08BR<\/a><\/li>\n<li>derived categories of modules (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08CV\">Tag 08CV<\/a><\/li>\n<li>D(QCoh(O_X) = D_{QCoh}(O_X) for X quasi-compact with\u00a0affine diagonal (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08DB\">Tag 08DB<\/a><\/li>\n<li>Lipman and Neeman&#8217;s result on approximation by perfect\u00a0complexes (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08ES\">Tag 08ES<\/a><\/li>\n<li>derived categories of modules (spaces),\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08EZ\">Tag 08EZ<\/a><\/li>\n<li>Induction principle for quasi-compact and quasi-separated\u00a0algebraic spaces using distinguished squares (this is really fun!)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08GL\">Tag 08GL<\/a><\/li>\n<li>derived Mayer-Vietoris using distinguished squares\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08GS\">Tag 08GS<\/a><\/li>\n<li>D(QCoh(O_X) = D_{QCoh}(O_X) for X quasi-compact with\u00a0affine diagonal (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08H1\">Tag 08H1<\/a><\/li>\n<li>approximation by perfect complexes (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08HP\">Tag 08HP<\/a><\/li>\n<li>bunch of improvements to the bibliography\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/bibliography\">bibliography<\/a><\/li>\n<li>being projective is not local on the base\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08J0\">Tag 08J0<\/a><\/li>\n<li>descent data for schemes need not be effective, even for\u00a0a projective morphism\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08KE\">Tag 08KE<\/a><\/li>\n<li>base change for Rf_*RHom(E, G) (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08IC\">Tag 08IC<\/a><\/li>\n<li>base change for Rf_*RHom(E, G) (spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08JM\">Tag 08JM<\/a><\/li>\n<li>the <i>Hom<\/i> functor\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08JS\">Tag 08JS<\/a><\/li>\n<li>the stack of coherent sheaves\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08WC\">Tag 08WC<\/a><\/li>\n<li>deformation theory: rings, modules, ringed spaces,\u00a0sheaves of modules on ringed spaces, ringed topoi,\u00a0sheaves of modules on ringed topoi\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08KX\">Tag 08KX<\/a><\/li>\n<li>subtopoi\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08LT\">Tag 08LT<\/a><\/li>\n<li>standard simplicial resolutions\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08N8\">Tag 08N8<\/a><\/li>\n<li>cotangent complex\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08P6\">Tag 08P6<\/a><\/li>\n<li>snake lemma now has a proof without picking elements\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/010H\">Tag 010H<\/a><\/li>\n<li>constructing polynomial resolutions\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08PX\">Tag 08PX<\/a><\/li>\n<li>(trivial) Kan fibrations\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08NK\">Tag 08NK<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08NT\">Tag 08NT<\/a><\/li>\n<li>Quillen&#8217;s spectral sequence\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08RF\">Tag 08RF<\/a><\/li>\n<li>cotangent complex and obstructions (algebra)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08SP\">Tag 08SP<\/a><\/li>\n<li>cotangent complex and obstructions (ringed spaces)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08UZ\">Tag 08UZ<\/a><\/li>\n<li>cotangent complex and obstructions (ringed topoi)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08V5\">Tag 08V5<\/a><\/li>\n<li>fixed an error in Artin&#8217;s axioms point out by David Rydh\u00a0<a href=\"https:\/\/github.com\/stacks\/stacks-project\/commit\/2ccbbe3087e4dc2b1df2193c81ede7486931424c\">2ccbbe3087e4dc2b1df2193c81ede7486931424c<\/a><\/li>\n<li>skeleton chapter on dualizing complexes (algebra)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08XH\">Tag 08XH<\/a><\/li>\n<li>descent for universally injective morphisms (thanks to Kiran Kedlaya)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08WE\">Tag 08WE<\/a><\/li>\n<\/ol>\n<p>This brings us up to May 1 of this year. At that point I started to work on a <a href=\"http:\/\/stacks.math.columbia.edu\/download\/proetale.pdf\">chapter on pro-\\&#8217;etale cohomology<\/a>, in order to advertise work by Bhargav Bhatt and Peter Scholze in some lectures in Stockholm (KTH). The authors graciously send me a copy of their (for the moment) unfinished manuscript. The chapter covers only a small part of their material, leading up to the definition of constructible complexes and the proper base change theorem. All mistakes are mine. I&#8217;ve tried to put most of the background material in other chapters. As is usual for the Stacks project, whenever you try to add something new you are forced to add a lot of background material to go along with it. Here is a list of some of the things we added.<\/p>\n<ol>\n<li>pro-\\&#8217;etale cohomology (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0966\">Tag 0966<\/a><\/li>\n<li>Gleason&#8217;s theorem on extremally disconnected spaces\u00a0(I strongly recommend the original paper)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08YH\">Tag 08YH<\/a><\/li>\n<li>Hochster&#8217;s spectral spaces\u00a0(I strongly recommend the original paper)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/08YF\">Tag 08YF<\/a><\/li>\n<li>Stone Cech compactification\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0908\">Tag 0908<\/a><\/li>\n<li>Olivier&#8217;s theorem on absolutely flat extensions of\u00a0strictly henselian rings\u00a0(I strongly recommend the original paper)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/092Z\">Tag 092Z<\/a><\/li>\n<li>weakly \\&#8217;etale morphisms (schemes)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/094N\">Tag 094N<\/a><\/li>\n<li>derived completion (algebra; I&#8217;ve tried to give\u00a0some references but I&#8217;d love to know more about the history\u00a0of this topic)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/091N\">Tag 091N<\/a><\/li>\n<li>constructible sheaves (etale)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/05BE\">Tag 05BE<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/095M\">Tag 095M<\/a><\/li>\n<li>derived completion (ringed topoi)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/0995\">Tag 0995<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/099L\">Tag 099L<\/a>\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/099P\">Tag 099P<\/a><\/li>\n<li>derived category D_c (etale)\u00a0<a href=\"http:\/\/stacks.math.columbia.edu\/tag\/095V\">Tag 095V<\/a><\/li>\n<\/ol>\n<p>Enjoy!<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Since the last update we have added the following material: universal property of blowing up (schemes) Tag 0806 admissible blowups (schemes) Tag 080J strict transform (schemes) Tag 080C a section on fitting ideals (algebra) Tag 07Z6 flattening by blowing up &hellip; <a href=\"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/?p=3265\">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-3265","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\/3265","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=3265"}],"version-history":[{"count":7,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3265\/revisions"}],"predecessor-version":[{"id":3272,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/3265\/revisions\/3272"}],"wp:attachment":[{"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3265"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3265"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.math.columbia.edu\/~dejong\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3265"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}