BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Barbara Fantechi (SISSA) DTSTART:20201016T190000Z DTEND:20201016T200000Z DTSTAMP:20260407T214608Z UID:agstanford/30 DESCRIPTION:Title: Infinitesimal deformations of semi-smooth varieties\nby Barbara Fa ntechi (SISSA) as part of Stanford algebraic geometry seminar\n\n\nAbstrac t\nThis is a report on joint work with Marco Franciosi and Rita Pardini. G eneralizing the standard definition for surfaces\, we call a variety $X$ ( over an alg closed field of char not 2) {\\em semi-smooth} if its singular ities are \\'etale locally either $uv=0$ or $u^2=v^2w$ (pinch point)\; equ ivalently\, if $X$ can be obtained by gluing a smooth variety (the normali zation of $X$) along an involution (with smooth quotient) on a smooth divi sor. They are the simplest singularities for non normal\, KSBA-stable surf aces.\nFor a semi-smooth variety $X$\, we calculate the tangent sheaf $T_X $ and the infinitesimal deformations sheaf ${\\mathcal T}^1_X:={\\mathcal E}xt^1(\\Omega_X\,\\mathcal O_X)$ which determine the infinitesimal deform ations and smoothability of $X$.\nAs an application\, we use Tziolas' form al smoothability criterion to show that every stable semi-smooth Godeaux s urface (classified by Franciosi\, Pardini and S\\"onke) corresponds to a s mooth point of the KSBA moduli space\, in the closure of the open locus of smooth surfaces.\n\nThe discussion for Barbara Fantechi’s talk is takin g place not in zoom-chat\, but at https://tinyurl.com/2020-10-16-bf (and will be deleted after ~3-7 days).\n LOCATION:https://researchseminars.org/talk/agstanford/30/ END:VEVENT END:VCALENDAR