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X-WR-CALNAME:Center for Complex Geometry
X-ORIGINAL-URL:https://ccg.ibs.re.kr
X-WR-CALDESC:Events for Center for Complex Geometry
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BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20210101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230302T110000
DTEND;TZID=Asia/Seoul:20230302T120000
DTSTAMP:20260417T073115
CREATED:20230214T023938Z
LAST-MODIFIED:20230214T023938Z
UID:2081-1677754800-1677758400@ccg.ibs.re.kr
SUMMARY:Yunhyung Cho\, Monotone Lagrangian Tori in Fano Varieties
DESCRIPTION:     Speaker\n\n\nYunhyung Cho\nSungkyunkwan University\n\n\n\n\n\n\nThis is a survey talk of current progress of mirror symmetry of Fano varieties. For a given smooth Fano variety X\, it has been conjectured that there exists a Laurent polynomial called a (weak) Landau-Ginzburg mirror (or weak LG mirror shortly) which encodes a quantum cohomology ring structure of X. Tonkonog proved that one can find a weak LG mirror using a monotone Lagrangian torus in X. In this talk I will explain how to find a monotone Lagrangian torus using a Fano toric degeneration of X. If time permits\, I will also describe a monotone Lagrangian torus in a given flag variety.
URL:https://ccg.ibs.re.kr/event/2023-03-02/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230301
DTEND;VALUE=DATE:20240229
DTSTAMP:20260417T073115
CREATED:20230425T013322Z
LAST-MODIFIED:20230504T065225Z
UID:2258-1677628800-1709164799@ccg.ibs.re.kr
SUMMARY:Insong Choe (최인송\, Konkuk University)
DESCRIPTION:Insong Choe (최인송) \nVisitor (2023.3.1-2024.2.28) from Konkuk University \nOffice: B255
URL:https://ccg.ibs.re.kr/event/230301-240228/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230228T111000
DTEND;TZID=Asia/Seoul:20230228T120000
DTSTAMP:20260417T073115
CREATED:20230212T131702Z
LAST-MODIFIED:20230213T043948Z
UID:2071-1677582600-1677585600@ccg.ibs.re.kr
SUMMARY:JongHae Keum\, Mori Dream Surfaces of General Type with pg=0
DESCRIPTION:     Speaker\n\n\nJongHae Keum\nKIAS\n\n\n\n\n\n\n(This is a part of Seminars on Algebraic Surfaces and Related Topics.) \nThe Cox ring of a variety is the total coordinate ring\, i.e.\, the direct sum of all spaces of global sections of all divisors. When this ring is finitely generated\, the variety is called Mori dream (MD). A necessary condition for being MD is the finite generatedness of Pic(X)\, i.e.\, the vanishing of the irregularity. Smooth rational surfaces with big anticanonical divisor are MD. So are all del Pezzo surfaces of any degree. A K3 surface or an Enriques surface with Picard number at least 3 is MD iff its automorphism group is finite. \nIn this talk I will consider the case of surfaces of general type with pg=0\, and provide several examples that are MD. I will also provide non-minimal examples that are not MD. This is a joint work with Kyoung-Seog Lee.
URL:https://ccg.ibs.re.kr/event/2023-02-28-1110-1200/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230228T100000
DTEND;TZID=Asia/Seoul:20230228T105000
DTSTAMP:20260417T073115
CREATED:20230212T131517Z
LAST-MODIFIED:20230212T131517Z
UID:2069-1677578400-1677581400@ccg.ibs.re.kr
SUMMARY:Dongsoo Shin\, Deformations of Sandwiched Surface Singularities and the Minimal Model Program
DESCRIPTION:     Speaker\n\n\nDongsoo Shin\nChungnam National U.\n\n\n\n\n\n\n(This is a part of Seminars on Algebraic Surfaces and Related Topics.) \nWe investigate the correspondence between three theories of deformations of rational surface singularities: de Jong and van Straten’s picture deformations\, Kollár’s P-resolutions\, and Pinkham’s smoothings of negative weights. We provide an explicit method for obtaining\, from a given deformation in one theory\, deformations in other theories that parameterize the same irreducible components of the deformation space of the singularity. We employ the semi-stable minimal model program significantly for this purpose. We prove Kollár conjecture for various sandwiched surface singularities as an application. This is a joint work with Heesang Park.
URL:https://ccg.ibs.re.kr/event/2023-02-28-1000-1050/
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:20260417T073115
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
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230227T155000
DTEND;TZID=Asia/Seoul:20230227T164000
DTSTAMP:20260417T073115
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:20230227T144000
DTEND;TZID=Asia/Seoul:20230227T153000
DTSTAMP:20260417T073115
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:20230227T133000
DTEND;TZID=Asia/Seoul:20230227T142000
DTSTAMP:20260417T073115
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;VALUE=DATE:20230227
DTEND;VALUE=DATE:20230301
DTSTAMP:20260417T073115
CREATED:20230127T105023Z
LAST-MODIFIED:20230213T044029Z
UID:2034-1677456000-1677628799@ccg.ibs.re.kr
SUMMARY:Seminars on Algebraic Surfaces and Related Topics
DESCRIPTION:     Schedule\n\n\nFeb. 27 \n\n\n\n\n\nN-resolutions\nGiancarlo Urzua (UC Chille)\n13:30-14:20 \n\n\nSmooth Projective Surfaces with Pseudo-effective Tangent Bundles\nGuolei Zhong (IBS-CCG)\n14:40-15:30 \n\n\nNodal Surfaces and Cubic Discriminants\nYonghwa Cho (IBS-CCG)\n15:50-16:40 \n\n\nLagrangian Fibration Structure on the Cotangent Bundle of a Del Pezzo Surface of Degree 4\nHosung Kim (IBS-CCG)\n17:00-17:50 \n\n\nDinner\n18:20-20:00\n\n\n\n\n\nFeb. 28 \n\n\n\n\n\nDeformations of Sandwiched Surface Singularities and the Minimal Model Program\nDongsoo Shin (Chungnam National U.)\n10:00-10:50 \n\n\nMori Dream Surfaces of General Type with pg=0\nJongHae Keum (KIAS)\n11:10-12:00 \n\n\nLunch\n12:00-13:00
URL:https://ccg.ibs.re.kr/event/2023-02-27-28/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Conferences and Workshops
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230213
DTEND;VALUE=DATE:20230218
DTSTAMP:20260417T073115
CREATED:20221221T053244Z
LAST-MODIFIED:20230221T074222Z
UID:1925-1676246400-1676678399@ccg.ibs.re.kr
SUMMARY:Korea-Japan Conference in Algebraic Geometry
DESCRIPTION:Speakers\nYonghwa Cho (IBS-CCG)\nJunho Choe (KIAS)\nYoshinori Gongyo (Tokyo U.)\nKenta Hashizume (Kyoto U.)\nSukmoon Huh (Sungkyunkwan U.)\nWonTae Hwang (Jeonbuk National U.)\nSeung-Jo Jung (Jeonbuk National U.)\nYeongrak Kim (Pusan National U.)\nTasuki Kinjo (IPMU\, Tokyo)\nTatsuki Kuwagaki (Kyoto U.)\nShin-ichi Matsumura (Tohoku U.)\nYosuke Matsuzawa (Osaka Metropolitan U.)\nJinhyung Park (KAIST)\nKenta Sato (Kyushu U.)\nJoonyeong Won (Ehwa Womans U.)\nShou Yoshikawa (RIKEN iTHEMS) \nAbstracts\nPDF File \nSchedule\nDay 1: February 13 (Monday) \n\n\n\n~10:00\nRegistration\n\n\n10:00~11:00\nJinhyung Park\nSyzygies of tangent developable surfaces and K3 carpets via secant varieties\nJun-Muk Hwang\n(Chair)\n\n\n11:00~11:30\nCoffee Break\n\n\n11:30~12:30\nShin-ichi Matsumura\nThe nonvanishing problem for varieties with nef anticanonical bundle\n\n\n12:30~14:30\nLunch\n\n\n15:00~16:00\nSeung-Jo Jung\nOn Milnor numbers and Tjurina numbers of hypersurface singularities\nYujiro Kawamata\n(Chair)\n\n\n16:00~16:20\nCoffee Break\n\n\n16:20-17:20\nYosuke Matsuzawa\nZariski dense orbit conjecture and arithmetic degrees of cohomologically hyperbolic maps\n\n\n18:00~20:00\nSpeakers Dinner\n\n\n\n  \nDay 2: February 14 (Tuesday) \n\n\n\n10:00~11:00\nYoshinori Gongyo\nGeneralized complexities and the Mukai type conjecture\nYongnam Lee\n(Chair)\n\n\n11:00~11:30\nCoffee Break\n\n\n11:30~12:30\nShou Yoshikawa\nQuasi-F-splitting\n\n\n12:30~14:30\nLunch\n\n\n15:00~16:00\nSukmoon Huh\nTorelli problem on logarithmic sheaves\nSijong Kwak\n(Chair)\n\n\n16:00~16:20\nCoffee Break\n\n\n16:20-17:20\nKenta Sato\nGeneral hyperplane section of log canonical threefolds in positive characteristic\n\n\n\n  \nDay 3: February 15 (Wednesday) \n\n\n\n10:00~11:00\nWonTae Hwang\nJordan constants of groups in connection with abelian varieties in positive characteristic\nDongseon Hwang\n(Chair)\n\n\n11:00~11:30\nCoffee Break\n\n\n11:30~12:30\nTasuki Kinjo\nEuler characteristic for stacks\n\n\n12:30~18:00\nExcursion\n\n\n\n  \nDay 4: February 16 (Thursday) \n\n\n\n10:00~11:00\nJunho Choe\nVarious parallels between projective varieties and secant varieties\nJaehyun Hong\n(Chair)\n\n\n11:00~11:30\nCoffee Break\n\n\n11:30~12:30\nTatsuki Kuwagaki\nSome examples of Hodge-Fukaya theory\n\n\n12:30~14:30\nLunch\n\n\n15:00~16:00\nJoonyeong Won\nTwisted Kaehler-Einstein metric on del Pezzo surfaces\nJongHae Keum\n(Chair)\n\n\n16:00~16:20\nCoffee Break\n\n\n16:20-17:20\nKenta Hashizume\nOn effective base point freeness for klt pairs\n\n\n17:30~19:00\nBanquet\n\n\n\n  \nDay 5: February 17 (Friday) \n\n\n\n10:00~11:00\nYeongrak Kim\nUlrich bundles on cubic fourfolds\nKeiji Oguiso\n(Chair)\n\n\n11:00~11:30\nCoffee Break\n\n\n11:30~12:30\nYonghwa Cho\nNodal (hyper-)surfaces\n\n\n\nOrganizers\nOsamu Fujino (Kyoto U.)\nDongSeon Hwang (IBS-CCG)\nJun-Muk Hwang (IBS-CCG)\nYongnam Lee (IBS-CCG)\nKeiji Oguiso (U. Tokyo)\nShunsuke Takagi (U. Tokyo) \nRegistration\nPlease submit Google form by January 31. \nMore Information\n• Food Zone Map\n• How to get to IBS-CCG
URL:https://ccg.ibs.re.kr/event/2023-02-13-17/
LOCATION:IBS Science Culture Center\, Daejeon\, Korea\, Republic of
CATEGORIES:Conferences and Workshops
ATTACH;FMTTYPE=image/jpeg:https://ccg.ibs.re.kr/wp-content/uploads/2022/12/KJ-conference-scaled.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230210T110000
DTEND;TZID=Asia/Seoul:20230210T120000
DTSTAMP:20260417T073115
CREATED:20230208T052107Z
LAST-MODIFIED:20230208T052107Z
UID:2056-1676026800-1676030400@ccg.ibs.re.kr
SUMMARY:Yoon-Joo Kim\, Isotrivial Fibrations of Compact Hyper-Kähler Manifolds
DESCRIPTION:     Speaker\n\n\nYoon-Joo Kim\nMPI-Bonn\n\n\n\n\n\n\nA compact hyper-Kähler (HK) manifold and its Lagrangian fibration are higher-dimensional generalizations of a K3 surface and its elliptic fibration. A Lagrangian fibration f : X → B of a HK manifold is called isotrivial if its smooth fibers are all isomorphic to each other; this is the most special type of Lagrangian fibrations\, generalizing the notion of an isotrivial elliptic fibration. In this talk\, I will propose a possible classification scheme of HK manifolds admitting isotrivial Lagrangian fibrations. This method in particular rediscovers the two well-known constructions of HK manifolds\, the K3[n] and generalized Kummer constructions. I will then specialize the discussion to HK fourfolds. This is joint work with Radu Laza and Olivier Martin.
URL:https://ccg.ibs.re.kr/event/2023-02-10/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230209T110000
DTEND;TZID=Asia/Seoul:20230209T120000
DTSTAMP:20260417T073115
CREATED:20230111T041445Z
LAST-MODIFIED:20230111T041455Z
UID:1998-1675940400-1675944000@ccg.ibs.re.kr
SUMMARY:Laurent Stolovitch\, Introduction to Normal Form Theory of Holomorphic Vector Fields 2
DESCRIPTION:     Speaker\n\n\nLaurent Stolovitch\nUniversite Cote d’Azur\n\n\n\n\n\n\nIn this short lecture\, I will introduce the notion of normal form and resonances. I will also explain the phenomenon of “small divisors” and give some fundamental results of holomorphic conjugacy to a normal form.
URL:https://ccg.ibs.re.kr/event/2023-02-09/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230207T160000
DTEND;TZID=Asia/Seoul:20230207T170000
DTSTAMP:20260417T073115
CREATED:20230111T041331Z
LAST-MODIFIED:20230111T041331Z
UID:1996-1675785600-1675789200@ccg.ibs.re.kr
SUMMARY:Laurent Stolovitch\, Introduction to Normal Form Theory of Holomorphic Vector Fields 1
DESCRIPTION:     Speaker\n\n\nLaurent Stolovitch\nUniversite Cote d’Azur\n\n\n\n\n\n\nIn this short lecture\, I will introduce the notion of normal form and resonances. I will also explain the phenomenon of “small divisors” and give some fundamental results of holomorphic conjugacy to a normal form.
URL:https://ccg.ibs.re.kr/event/2023-02-07/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230207T110000
DTEND;TZID=Asia/Seoul:20230207T120000
DTSTAMP:20260417T073115
CREATED:20230127T104147Z
LAST-MODIFIED:20230127T104147Z
UID:2032-1675767600-1675771200@ccg.ibs.re.kr
SUMMARY:Daniele Agostini\, The Martens-Mumford Theorem and the Green-Lazarsfeld Secant Conjecture
DESCRIPTION:     Speaker\n\n\nDaniele Agostini\nEberhard Karls Universität Tübingen\n\n\n\n\n\n\nThe syzygies of a curve are the algebraic relation amongst the equation defining it. They are an algebraic concept but they have surprising applications to geometry. For example\, the Green-Lazarsfeld secant conjecture predicts that the syzygies of a curve of sufficiently high degree are controlled by its special secants. We prove this conjecture for all curves of Clifford index at least two and not bielliptic and for all line bundles of a certain degree. Our proof is based on a classic result of Martens and Mumford on Brill-Noether varieties and on a simple vanishing criterion that comes from the interpretation of syzygies through symmetric products of curves.
URL:https://ccg.ibs.re.kr/event/2023-02-07-1100-1200/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230206
DTEND;VALUE=DATE:20230210
DTSTAMP:20260417T073115
CREATED:20230119T042147Z
LAST-MODIFIED:20230119T042147Z
UID:2009-1675641600-1675987199@ccg.ibs.re.kr
SUMMARY:Eunjeong Lee (이은정\, Chungbuk National University)
DESCRIPTION:Eunjeong Lee \nVisitor (2023.2.6-2023.2.9) from Chungbuk National University\nOffice: –
URL:https://ccg.ibs.re.kr/event/230206-230209/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230204
DTEND;VALUE=DATE:20230211
DTSTAMP:20260417T073115
CREATED:20221130T080619Z
LAST-MODIFIED:20230119T042848Z
UID:1893-1675468800-1676073599@ccg.ibs.re.kr
SUMMARY:Laurent Stolovitch (Universite Cote d'Azur\, France)
DESCRIPTION:Laurent Stolovitch \nVisitor (2023.2.4-2023.2.10) from Universite Cote d’Azur\, France \nOffice: –
URL:https://ccg.ibs.re.kr/event/230204-230210/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230203
DTEND;VALUE=DATE:20230210
DTSTAMP:20260417T073115
CREATED:20230119T041702Z
LAST-MODIFIED:20230119T042250Z
UID:2005-1675382400-1675987199@ccg.ibs.re.kr
SUMMARY:Antonio Nigro (Universidade Federal Fluminense)
DESCRIPTION:Antonio Nigro \nVisitor (2023.2.3-2023.2.9) from Universidade Federal Fluminense\nOffice: –
URL:https://ccg.ibs.re.kr/event/230203-230209/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230202T160000
DTEND;TZID=Asia/Seoul:20230202T170000
DTSTAMP:20260417T073115
CREATED:20221222T052415Z
LAST-MODIFIED:20221222T052415Z
UID:1936-1675353600-1675357200@ccg.ibs.re.kr
SUMMARY:Dennis The\, A Cartan-theoretic Perspective on (2\,3\,5)-distributions
DESCRIPTION:     Speaker\n\n\nDennis The\nUiT The Arctic University of Norway\n\n\n\n\n\n\nGeneric rank 2 distributions on 5-manifolds\, i.e. “(2\,3\,5)-distributions”\, are interesting geometric structures arising in the study of non-holonomic systems\, underdetermined ODE of Monge type\, conformal 5-manifolds with special holonomy\, etc. The origins of their study date to Élie Cartan’s “5-variables” paper of 1910\, where he gave a tour-de-force application of his method of equivalence. In my talk\, I’ll revisit the classification of homogeneous (2\,3\,5)-distributions from a modern “Cartan-theoretic” perspective. In particular\, I’ll discuss from this viewpoint the exceptionality of the 3:1 ratio for two spheres rolling on each other without twisting or slipping.
URL:https://ccg.ibs.re.kr/event/2023-02-02/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230130
DTEND;VALUE=DATE:20230209
DTSTAMP:20260417T073115
CREATED:20221130T075502Z
LAST-MODIFIED:20230119T042807Z
UID:1883-1675036800-1675900799@ccg.ibs.re.kr
SUMMARY:Dennis The (University of Tromso\, Norway)
DESCRIPTION:Dennis The \nVisitor (2023.1.30-2023.2.8) from University of Tromso\, Norway  \nOffice: –
URL:https://ccg.ibs.re.kr/event/230130-230208/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230127T103000
DTEND;TZID=Asia/Seoul:20230127T113000
DTSTAMP:20260417T073115
CREATED:20221219T040333Z
LAST-MODIFIED:20221229T014331Z
UID:1917-1674815400-1674819000@ccg.ibs.re.kr
SUMMARY:Kangjin Han\, Secant variety and its singularity II
DESCRIPTION:     Speaker\n\n\nKangjin Han\nDGIST\n\n\n\n\n\n\nSecant variety (or more generally Join) construction is one of the main methods to construct a new geometric object from the original one in classical algebraic geometry. In this series of talks\, we first consider some general facts on secant varieties and then focus on a specific topic\, i.e. singularity of secants. For this purpose\, we review some basic facts and known results in the literature and present some ideas to show (non-)singularity of points in the given secant. We also report a recent work with K. Furukawa on the singular loci of higher secant of Veronese varieties and others. The talks cover such topics as Terracini lemma\, identifiability\, tangential k-contact locus from geometric side and apolar ideal and defining equations via a Young flattening and so on from algebraic side.
URL:https://ccg.ibs.re.kr/event/2023-01-27/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230126T160000
DTEND;TZID=Asia/Seoul:20230126T170000
DTSTAMP:20260417T073115
CREATED:20221219T040137Z
LAST-MODIFIED:20221229T014257Z
UID:1914-1674748800-1674752400@ccg.ibs.re.kr
SUMMARY:Kangjin Han\, Secant variety and its singularity I
DESCRIPTION:     Speaker\n\n\nKangjin Han\nDGIST\n\n\n\n\n\n\nSecant variety (or more generally Join) construction is one of the main methods to construct a new geometric object from the original one in classical algebraic geometry. In this series of talks\, we first consider some general facts on secant varieties and then focus on a specific topic\, i.e. singularity of secants. For this purpose\, we review some basic facts and known results in the literature and present some ideas to show (non-)singularity of points in the given secant. We also report a recent work with K. Furukawa on the singular loci of higher secant of Veronese varieties and others. The talks cover such topics as Terracini lemma\, identifiability\, tangential k-contact locus from geometric side and apolar ideal and defining equations via a Young flattening and so on from algebraic side.
URL:https://ccg.ibs.re.kr/event/2023-01-26/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230113T110000
DTEND;TZID=Asia/Seoul:20230113T120000
DTSTAMP:20260417T073115
CREATED:20221228T083306Z
LAST-MODIFIED:20230110T055934Z
UID:1947-1673607600-1673611200@ccg.ibs.re.kr
SUMMARY:JongHae Keum\, Fake Projective Plane II
DESCRIPTION:     Speaker\n\n\nJongHae Keum\nKIAS\n\n\n\n\n\n\nFake projective planes (abbreviated as FPPs) are 2-dimensional complex manifolds with the same Betti numbers as the projective plane\, but not isomorphic to it. \nFPPs can be uniformized by a complex 2-ball. In other words\, they are ball quotients having the minimum possible Betti numbers. \nThe existence of such a surface was first proved by Mumford in 1979\, via 2-adic uniformization. \nNot always algebraic varieties are described via polynomial equations: sometimes they are constructed via uniformization: this means\, as quotients of certain domains in a complex vector space\, called bounded symmetric domains\, via the action of discontinuous groups. Then general theorems (as Kodaira’s) imply the algebraicity of these quotient complex manifolds. The problem concerning the algebro-geometrical properties of such varieties constructed via uniformization and especially the description of their projective embeddings (and the corresponding polynomial equations) lies at the crossroads of several allied fields: the theory of arithmetic groups and division algebras\, complex algebraic and differential geometry\, linear systems\, use of group symmetries\, and topological and homological tools in the study of quotient spaces. Of particular importance are the so-called ball quotients\, especially in dimension 2\, since they yield the surfaces with the maximal possible canonical volume K2 for a fixed value of the geometric genus pg. \nIn the first lecture I will introduce basic properties of FPPs and their position in the classification theory of algebraic surfaces. \nIn the second I will discuss recent progress on them\, such as their derived categories\, bicanonical maps and their equations.
URL:https://ccg.ibs.re.kr/event/2023-01-13/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230112T160000
DTEND;TZID=Asia/Seoul:20230112T170000
DTSTAMP:20260417T073115
CREATED:20221228T083141Z
LAST-MODIFIED:20230110T055908Z
UID:1944-1673539200-1673542800@ccg.ibs.re.kr
SUMMARY:JongHae Keum\, Fake Projective Planes I
DESCRIPTION:     Speaker\n\n\nJongHae Keum\nKIAS\n\n\n\n\n\n\nFake projective planes (abbreviated as FPPs) are 2-dimensional complex manifolds with the same Betti numbers as the projective plane\, but not isomorphic to it. \nFPPs can be uniformized by a complex 2-ball. In other words\, they are ball quotients having the minimum possible Betti numbers. \nThe existence of such a surface was first proved by Mumford in 1979\, via 2-adic uniformization. \nNot always algebraic varieties are described via polynomial equations: sometimes they are constructed via uniformization: this means\, as quotients of certain domains in a complex vector space\, called bounded symmetric domains\, via the action of discontinuous groups. Then general theorems (as Kodaira’s) imply the algebraicity of these quotient complex manifolds. The problem concerning the algebro-geometrical properties of such varieties constructed via uniformization and especially the description of their projective embeddings (and the corresponding polynomial equations) lies at the crossroads of several allied fields: the theory of arithmetic groups and division algebras\, complex algebraic and differential geometry\, linear systems\, use of group symmetries\, and topological and homological tools in the study of quotient spaces. Of particular importance are the so-called ball quotients\, especially in dimension 2\, since they yield the surfaces with the maximal possible canonical volume K2 for a fixed value of the geometric genus pg. \nIn the first lecture I will introduce basic properties of FPPs and their position in the classification theory of algebraic surfaces. \nIn the second I will discuss recent progress on them\, such as their derived categories\, bicanonical maps and their equations.
URL:https://ccg.ibs.re.kr/event/2023-01-12/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230104
DTEND;VALUE=DATE:20230107
DTSTAMP:20260417T073115
CREATED:20230105T014437Z
LAST-MODIFIED:20230105T014437Z
UID:1991-1672790400-1673049599@ccg.ibs.re.kr
SUMMARY:Yunhyung Cho (조윤형\, Sungkyunkwan University)
DESCRIPTION:Yunhyung Cho (조윤형) \nVisitor (2023.1.4-2023.1.6) from Sungkyunkwan University\nOffice: –
URL:https://ccg.ibs.re.kr/event/yunhyung-cho-230104-230106/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221129T170000
DTEND;TZID=Asia/Seoul:20221129T180000
DTSTAMP:20260417T073115
CREATED:20221128T014815Z
LAST-MODIFIED:20221128T015115Z
UID:1875-1669741200-1669744800@ccg.ibs.re.kr
SUMMARY:Andrea Petracci\, A 1-dimensional Component of K-moduli of Del Pezzo Surfaces
DESCRIPTION:     Speaker\n\n\nAndrea Petracci\nUniversità di Bologna\n\n\n\n\n\n\nFano varieties are algebraic varieties with positive curvature; they are basic building blocks of algebraic varieties. Great progress has been recently made by Xu et al. to construct moduli spaces of Fano varieties by using K-stability (which is related to the existence of Kähler-Einstein metrics). These moduli spaces are called K-moduli. \nIn this talk I will explain how to easily deduce some geometric properties of K-moduli by using toric geometry and deformation theory. In particular\, I will show how to construct a 1-dimensional component of K-moduli which parametrises certain K-polystable del Pezzo surfaces.
URL:https://ccg.ibs.re.kr/event/2022-11-29/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221115T110000
DTEND;TZID=Asia/Seoul:20221115T120000
DTSTAMP:20260417T073115
CREATED:20221128T014505Z
LAST-MODIFIED:20221128T014612Z
UID:1858-1668510000-1668513600@ccg.ibs.re.kr
SUMMARY:Joaquín Moraga\, Coregularity of Fano Varieties
DESCRIPTION:     Speaker\n\n\nJoaquín Moraga\nUCLA\n\n\n\n\n\n\nIn this talk\, we will introduce the absolute coregularity of Fano varieties. The coregularity measures the singularities of the anti-pluricanonical sections. Philosophically\, most Fano varieties have coregularity 0. In the talk\, we will explain some theorems that support this philosophy. We will show that a Fano variety of coregularity 0 admits a non-trivial section in |-2KX|\, independently of the dimension of X. This is joint work with Fernando Figueroa\, Stefano Filipazzo\, and Junyao Peng.
URL:https://ccg.ibs.re.kr/event/2022-11-15/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221101T163000
DTEND;TZID=Asia/Seoul:20221101T173000
DTSTAMP:20260417T073115
CREATED:20221025T025750Z
LAST-MODIFIED:20221025T025750Z
UID:1845-1667320200-1667323800@ccg.ibs.re.kr
SUMMARY:Junho Choe\, Constructions of Counterexamples to the Regularity Conjecture
DESCRIPTION:     Speaker\n\n\nJunho Choe\nKIAS\n\n\n\n\n\n\nCastelnuovo-Mumford regularity\, simply regularity\, is one of the most interesting invariants in projective algebraic geometry\, and the regularity conjecture due to Eisenbud and Goto says that the regularity can be controlled by the degree for any projective variety. But counterexamples to the conjecture have been constructed by some methods. In this talk we review the counterexample constructions including the Rees-like algebra method by McCullough and Peeva and the unprojection method.
URL:https://ccg.ibs.re.kr/event/2022-11-01-1630/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221101T150000
DTEND;TZID=Asia/Seoul:20221101T160000
DTSTAMP:20260417T073115
CREATED:20221025T025538Z
LAST-MODIFIED:20221025T025538Z
UID:1842-1667314800-1667318400@ccg.ibs.re.kr
SUMMARY:Livia Campo\, Fano 3-folds and Equivariant Unprojections
DESCRIPTION:     Speaker\n\n\nLivia Campo\nKIAS\n\n\n\n\n\n\nThe classification of terminal Fano 3-folds has been tackled from different directions: for instance\, using the Minimal Model Program\, via explicit Birational Geometry\, and via Graded Rings methods. In this talk I would like to introduce the Graded Ring Database – an upper bound to the numerics of Fano 3-folds – and discuss the role it plays in the classification and construction of codimension 4 Fano 3-folds having Fano index 2.
URL:https://ccg.ibs.re.kr/event/2022-11-01-1500/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221027T110000
DTEND;TZID=Asia/Seoul:20221027T120000
DTSTAMP:20260417T073115
CREATED:20220907T075418Z
LAST-MODIFIED:20221011T102020Z
UID:1701-1666868400-1666872000@ccg.ibs.re.kr
SUMMARY:Jaewoo Jeong\, Hankel Index of Smooth Non-ACM Curves of Almost Minimal Degree
DESCRIPTION:     Speaker\n\n\nJaewoo Jeong IBS CCG\n\n\n\n\n \nThe Hankel index of a real variety is a semi-algebraic invariant that quantifies the (structural) difference between nonnegative quadrics and sums of squares on the variety. Note that the Hankel index of a variety is difficult to compute and was computed for just few cases. In 2017\, Blekherman\, Sinn\, and Velasco provided an captivating (lower) bound of the Hankel index of a variety by an algebraic invariant\, Green-Lazarsfeld index\, of the variety. In particular\, if the variety X is an arithmetrically Cohen-Macaulay (ACM) variety of almost minimal degree\, then the Hankel index of X equals to the Green-Lazarsfeld index of X plus one (which is the equality case of the bound). We study the Hankel index of smooth non-ACM curves of almost minimal degree. Note that the curve is the image of the projection of rational normal curves away from an outer point. It is known that the Green-Lazarsfeld index of the curve is determined by the rank of the center of the projection with respect to the rational normal curve. We found a new rank of the center that detects the Hankel index of the rational curves. In addition\, it turns out that the rational curves are the first class of examples that the lower bound of the Hankel index is strict.
URL:https://ccg.ibs.re.kr/event/2022-10-27/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221013T110000
DTEND;TZID=Asia/Seoul:20221013T120000
DTSTAMP:20260417T073115
CREATED:20220830T070032Z
LAST-MODIFIED:20220928T015047Z
UID:1693-1665658800-1665662400@ccg.ibs.re.kr
SUMMARY:Jinhyun Park\, A Reciprocity Theorem Arising from a Family of Algebraic Curves
DESCRIPTION:     Speaker\n\n\nJinhyun Park\nKAIST\n\n\n\n\n\n\nThe classical reciprocity theorem\, also called the residue theorem\, states that the sum of the residues of a rational (meromorphic) differential form on a compact Riemann surface is zero. Its generalization to smooth projective curves over a field is often called the Tate reciprocity theorem. \nThere is a different “multiplicative version” too. Here\, instead of a rational form\, one uses a pair of rational functions on a smooth projective curve\, and instead of residues\, one uses “Tame symbols”. The corresponding global result is called the Weil reciprocity. This result is elegantly reformulated in terms of the Milnor K-theory\, and it is generalized to sequences of rational functions by A. Suslin. This Suslin reciprocity was recently strengthened by D. Rudenko\, resolving a conjecture of A. Goncharov. \nIn this talk\, let me sketch my recent work in-progress\, that studies a different kind of reciprocity results coming from a proper family of algebraic curves over an algebraically closed field of characteristic 0.
URL:https://ccg.ibs.re.kr/event/2022-10-13/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
END:VCALENDAR