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X-WR-CALDESC:Events for Center for Complex Geometry
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TZID:Asia/Seoul
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TZOFFSETFROM:+0900
TZOFFSETTO:+0900
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DTSTART:20220101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230227T133000
DTEND;TZID=Asia/Seoul:20230227T142000
DTSTAMP:20260526T021340
CREATED:20230212T130036Z
LAST-MODIFIED:20230212T130036Z
UID:2059-1677504600-1677507600@ccg.ibs.re.kr
SUMMARY:Giancarlo Urzua\, N-resolutions
DESCRIPTION:     Speaker\n\n\nGiancarlo Urzua\nUC Chille\n\n\n\n\n\n\n(This is a part of Seminars on Algebraic Surfaces and Related Topics.) \nI will introduce N-resolutions\, which are the negative analog of the Kollár–Shepherd-Barron (1988) P-resolutions of a 2-dimensional cyclic quotient singularity. (We instead work with the corresponding M-resolutions of Benkhe-Christophersen (1994).) I will start by describing an algorithm to find all of them based on the explicit algorithm for P-resolutions in Park-Park-Shin-Urzúa (2018) (that geometrically recovers Christophersen-Stevens’ zero continued fractions correspondence (1991))\, which in turn is based on the explicit MMP described by Hacking-Tevelev-Urzúa (HTU 2017). I will also describe another way to find N-resolutions via antiflips (HTU 2017) starting with an M-resolution\, showing an action of the braid group on all its associated Wahl resolutions. This will bring us to Hacking exceptional collections (2013-2016) on surfaces that are Q-Gorenstein smoothings of particular singular surfaces\, where Karmazyn-Kuznetsov-Shinder (2022) have described their derived categories via derived categories of the Kalck-Karmazyn algebras (2017). This can be put together through Kawamata’s bundles (2018-2022)\, and I will describe our main theorem on semi-orthogonal decompositions defined by these M- and N-resolutions. I will end with applications to all simply-connected Dolgachev surfaces. I will mention open problems. This is on the joint recent work with Jenia Tevelev. This computer program finds all M- and N-resolutions.
URL:https://ccg.ibs.re.kr/event/2023-02-27-1330-1420/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230227T144000
DTEND;TZID=Asia/Seoul:20230227T153000
DTSTAMP:20260526T021340
CREATED:20230212T130439Z
LAST-MODIFIED:20230212T130439Z
UID:2063-1677508800-1677511800@ccg.ibs.re.kr
SUMMARY:Guolei Zhong\, Smooth Projective Surfaces with Pseudo-effective Tangent Bundles
DESCRIPTION:     Speaker\n\n\nGuolei Zhong\nIBS CCG\n\n\n\n\n\n\n(This is a part of Seminars on Algebraic Surfaces and Related Topics.) \nA vector bundle over a projective manifold is said to be pseudo-effective if the tautological line bundle of its Grothendieck projectivization is pseudo-effective. In this talk\, I will show that a smooth non-uniruled projective surface S has pseudo-effective tangent bundle if and only if S is minimal and has vanishing second Chern class. Moreover\, I will describe the non-rational ruled surface and its blow-up which has pseudo-effective tangent bundles. This is a joint work with Jia Jia and Yongnam Lee.
URL:https://ccg.ibs.re.kr/event/2023-02-27-1440-1530/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230227T155000
DTEND;TZID=Asia/Seoul:20230227T164000
DTSTAMP:20260526T021340
CREATED:20230212T130812Z
LAST-MODIFIED:20230212T130812Z
UID:2065-1677513000-1677516000@ccg.ibs.re.kr
SUMMARY:Yonghwa Cho\, Nodal Surfaces and Cubic Discriminants
DESCRIPTION:     Speaker\n\n\nYonghwa Cho\nIBS CCG\n\n\n\n\n\n\n(This is a part of Seminars on Algebraic Surfaces and Related Topics.) \nIn this talk\, I will explain how to associate a nodal surface in P3 with a cubic hypersurface\, generalizing the method by Togliatti who constructed quintics with 31 nodes via a discriminant of a nodal cubic 4-folds. For low degrees(≤5)\, these constructions help to understand the classification problem of nodal surfaces\, especially when the surface has the maximal number of nodes. For higher degrees the things get more complicated. I will explain our recent result on sextics proving that every nodal sextics with maximal number of nodes admit Togliatti type descriptions. This talk is based on joint works with Fabrizio Catanese\, Stephen Coughlan\, Davide Frapporti\, Michael Kiermaier\, and Sascha Kurz.
URL:https://ccg.ibs.re.kr/event/2023-02-27-1550-1640/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230227T170000
DTEND;TZID=Asia/Seoul:20230227T175000
DTSTAMP:20260526T021340
CREATED:20230212T131137Z
LAST-MODIFIED:20230212T131200Z
UID:2067-1677517200-1677520200@ccg.ibs.re.kr
SUMMARY:Hosung Kim\, Lagrangian Fibration Structure on the Cotangent Bundle of a Del Pezzo Surface of Degree 4
DESCRIPTION:     Speaker\n\n\nHosung Kim\nIBS CCG\n\n\n\n\n\n\n(This is a part of Seminars on Algebraic Surfaces and Related Topics.) \nThe cotangent bundle of a complex projective manifold carries a natural holomorphic symplectic 2-form. The existence of a natural Lagrangian fibration structure of these non-compact complex manifolds has not been studied very much. In this talk\, I will present a natural Lagrangian fibration structure on the map from the cotangent bundle of a del Pezzo surface of degree 4. This is a joint work with Prof. Yongnam Lee.
URL:https://ccg.ibs.re.kr/event/2023-02-27-1700-1750/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
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