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PRODID:-//Center for Complex Geometry - ECPv6.15.20//NONSGML v1.0//EN
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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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X-Robots-Tag:noindex
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BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20240101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250301
DTEND;VALUE=DATE:20260216
DTSTAMP:20260415T203308
CREATED:20250304T080834Z
LAST-MODIFIED:20250304T081528Z
UID:3669-1740787200-1771199999@ccg.ibs.re.kr
SUMMARY:Ngoc Cuong Nguyen (KAIST)
DESCRIPTION:Ngoc Cuong Nguyen\nVisitor (2025.3.1-2026.2.15) from KAIST\nOffice: B248
URL:https://ccg.ibs.re.kr/event/250301-260215/
CATEGORIES:Visitors
ATTACH;FMTTYPE=image/jpeg:https://ccg.ibs.re.kr/wp-content/uploads/2025/03/ncnguyen_rescaled-1.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250326
DTEND;VALUE=DATE:20250503
DTSTAMP:20260415T203308
CREATED:20250402T020950Z
LAST-MODIFIED:20250402T020950Z
UID:3736-1742947200-1746230399@ccg.ibs.re.kr
SUMMARY:Mihai Paun (Universität Bayreuth)
DESCRIPTION:Mihai Paun\nVisitor (2025.3.26-2025.5.2) from Universität Bayreuth\nOffice: B249
URL:https://ccg.ibs.re.kr/event/250326-250502/
CATEGORIES:Visitors
ATTACH;FMTTYPE=image/jpeg:https://ccg.ibs.re.kr/wp-content/uploads/2022/09/mpaun-1-e1743559781998.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250331T110000
DTEND;TZID=Asia/Seoul:20250331T120000
DTSTAMP:20260415T203308
CREATED:20250313T065542Z
LAST-MODIFIED:20250325T081534Z
UID:3684-1743418800-1743422400@ccg.ibs.re.kr
SUMMARY:Mihai Paun\, Positivity of quotients of holomorphic tensor fields (Lecture I)
DESCRIPTION:    Speaker\n\n\nMihai Paun\nU. Bayreuth\n\n\n\n\n\n\nI will present the main results and techniques in the preprint arxiv:2502.02183 (joint with J. Cao). This was motivated by the recent preprint by W. Ou\, cf. arXiv:2501.1808 (especially by the algebraicity criteria for foliations on compact Kähler manifolds in this article). \nThe first lecture is dedicated to the proof of the aforementioned algebraicity criteria. Two main techniques are coming into the picture here. One is the usual substitute for the absence of ample line bundles on compact Kähler manifolds\, i.e. the Monge-Ampère equation (combined with the mass concentration method). The second one concerns basic properties of Lelong numbers of closed positive currents. \nIn the second lecture I will survey a few results concerning the positivity of direct images\, and the finally I will explain the proof of the main results (i.e. the complete generalisation to the Kähler case of the results obtained in collaboration with F. Campana).
URL:https://ccg.ibs.re.kr/event/2025-0331/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250401T110000
DTEND;TZID=Asia/Seoul:20250401T120000
DTSTAMP:20260415T203308
CREATED:20250313T065849Z
LAST-MODIFIED:20250325T081601Z
UID:3686-1743505200-1743508800@ccg.ibs.re.kr
SUMMARY:Mihai Paun\, Positivity of quotients of holomorphic tensor fields (Lecture II)
DESCRIPTION:    Speaker\n\n\nMihai Paun\nU. Bayreuth\n\n\n\n\n\n\nI will present the main results and techniques in the preprint arxiv:2502.02183 (joint with J. Cao). This was motivated by the recent preprint by W. Ou\, cf. arXiv:2501.1808 (especially by the algebraicity criteria for foliations on compact Kähler manifolds in this article). \nThe first lecture is dedicated to the proof of the aforementioned algebraicity criteria. Two main techniques are coming into the picture here. One is the usual substitute for the absence of ample line bundles on compact Kähler manifolds\, i.e. the Monge-Ampère equation (combined with the mass concentration method). The second one concerns basic properties of Lelong numbers of closed positive currents. \nIn the second lecture I will survey a few results concerning the positivity of direct images\, and the finally I will explain the proof of the main results (i.e. the complete generalisation to the Kähler case of the results obtained in collaboration with F. Campana).
URL:https://ccg.ibs.re.kr/event/2025-0401/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250402T140000
DTEND;TZID=Asia/Seoul:20250402T150000
DTSTAMP:20260415T203308
CREATED:20250318T131130Z
LAST-MODIFIED:20250318T131609Z
UID:3702-1743602400-1743606000@ccg.ibs.re.kr
SUMMARY:Thibaut Delcroix\, Weighted Kähler geometry and semisimple principal fibrations (Lecture I)
DESCRIPTION:    Speaker\n\n\nThibaut Delcroix\nUniversité de Montpellier\n\n\n\n\n\n\nIn Kähler geometry\, especially in the questions of existence of canonical Kähler metrics\, the volume form ωn associated with a Kähler form ω plays a central role. In weighted Kähler geometry\, we consider a Kähler manifold X equipped with a Hamiltonian action of a torus T\, a moment map μ and associated moment polytope Δ=μ(X). We fix a weight function v:Δ → (0\,+∞)\, then replace the volume form ωn by v ◦ μ ωn. One can then define new canonical Kähler metrics: weighted solitons and weighted cscK metrics (introduced by Lahdili)\, which include most classical canonical Kähler metrics. \nI will first introduce this weighted setting\, then the (analytic) weighted delta invariant\, a number that encodes the existence of weighted solitons. I will then present a sufficient condition of existence of weighted cscK metrics\, in line with the J-flow approach of Song-Weinkove. Then I will focus on the semisimple principal fibration cosntruction\, a construction of varieties from a principal torus bundle and a fiber. The link with weighted Kähler geometry is that\, under assumptions on the principal bundle\, the Kähler geometry of the total space reduces to the weighted Kähler geometry of the fiber.
URL:https://ccg.ibs.re.kr/event/2025-0402-2/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250402T160000
DTEND;TZID=Asia/Seoul:20250402T170000
DTSTAMP:20260415T203308
CREATED:20250313T065957Z
LAST-MODIFIED:20250331T055034Z
UID:3690-1743609600-1743613200@ccg.ibs.re.kr
SUMMARY:Mihai Paun\, Hermitian-Einstein metrics for stable coherent sheaves and Bogomolov-Gieseker inequality(Lecture III)
DESCRIPTION:    Speaker\n\n\nMihai Paun\nU. Bayreuth\n\n\n\n\n\n\nI will survey the main results obtained in the articles arXiv:2501.18088 and arXiv:2405.10003. There will be no “serious” proofs\, I will nevertheless try to highlight the main ingredients in our arguments.
URL:https://ccg.ibs.re.kr/event/2025-0402/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250403T110000
DTEND;TZID=Asia/Seoul:20250403T120000
DTSTAMP:20260415T203308
CREATED:20250304T060837Z
LAST-MODIFIED:20250313T070340Z
UID:3664-1743678000-1743681600@ccg.ibs.re.kr
SUMMARY:Jinhyung Park\, Effective gonality theorem on weight-one syzygies of algebraic curves
DESCRIPTION:    Speaker\n\n\nJinhyung Park\nKAIST\n\n\n\n\n\n\nIn 1986\, Green-Lazarsfeld raised the gonality conjecture asserting that the gonality gon(C) of a smooth projective curve C of genus g can be read off from weight-one syzygies of a sufficiently positive line bundle L\, and also proposed possible least degree of L\, that is 2g+gon(C)-1. In 2015\, Ein-Lazarsfeld proved the conjecture when deg(L) is sufficiently large\, but the effective part of the conjecture remained widely open and was reformulated explicitly by Farkas-Kemeny a few years ago. We show an effective vanishing theorem for weight-one syzygies\, which implies that the gonality conjecture holds if deg(L) is at least 2g+gon(C) or equal to 2g+gon(C)-1 and C is not a plane curve. As Castryck observed that the gonality conjecture may not hold for a plane curve when deg(L)=2g+gon(C)-1\, this result is the best possible and thus gives a complete answer to the gonality conjecture. This is joint work with Wenbo Niu.
URL:https://ccg.ibs.re.kr/event/2025-0403/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250404T140000
DTEND;TZID=Asia/Seoul:20250404T150000
DTSTAMP:20260415T203308
CREATED:20250318T131808Z
LAST-MODIFIED:20250318T131808Z
UID:3707-1743775200-1743778800@ccg.ibs.re.kr
SUMMARY:Thibaut Delcroix\, Weighted Kähler geometry and semisimple principal fibrations (Lecture II)
DESCRIPTION:    Speaker\n\n\nThibaut Delcroix\nUniversité de Montpellier\n\n\n\n\n\n\nIn Kähler geometry\, especially in the questions of existence of canonical Kähler metrics\, the volume form ωn associated with a Kähler form ω plays a central role. In weighted Kähler geometry\, we consider a Kähler manifold X equipped with a Hamiltonian action of a torus T\, a moment map μ and associated moment polytope Δ=μ(X). We fix a weight function v:Δ → (0\,+∞)\, then replace the volume form ωn by v ◦ μ ωn. One can then define new canonical Kähler metrics: weighted solitons and weighted cscK metrics (introduced by Lahdili)\, which include most classical canonical Kähler metrics. \nI will first introduce this weighted setting\, then the (analytic) weighted delta invariant\, a number that encodes the existence of weighted solitons. I will then present a sufficient condition of existence of weighted cscK metrics\, in line with the J-flow approach of Song-Weinkove. Then I will focus on the semisimple principal fibration cosntruction\, a construction of varieties from a principal torus bundle and a fiber. The link with weighted Kähler geometry is that\, under assumptions on the principal bundle\, the Kähler geometry of the total space reduces to the weighted Kähler geometry of the fiber.
URL:https://ccg.ibs.re.kr/event/2025-0404/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250407T140000
DTEND;TZID=Asia/Seoul:20250407T150000
DTSTAMP:20260415T203308
CREATED:20250318T131936Z
LAST-MODIFIED:20250318T131936Z
UID:3709-1744034400-1744038000@ccg.ibs.re.kr
SUMMARY:Thibaut Delcroix\, Weighted Kähler geometry and semisimple principal fibrations (Lecture III)
DESCRIPTION:    Speaker\n\n\nThibaut Delcroix\nUniversité de Montpellier\n\n\n\n\n\n\nIn Kähler geometry\, especially in the questions of existence of canonical Kähler metrics\, the volume form ωn associated with a Kähler form ω plays a central role. In weighted Kähler geometry\, we consider a Kähler manifold X equipped with a Hamiltonian action of a torus T\, a moment map μ and associated moment polytope Δ=μ(X). We fix a weight function v:Δ → (0\,+∞)\, then replace the volume form ωn by v ◦ μ ωn. One can then define new canonical Kähler metrics: weighted solitons and weighted cscK metrics (introduced by Lahdili)\, which include most classical canonical Kähler metrics. \nI will first introduce this weighted setting\, then the (analytic) weighted delta invariant\, a number that encodes the existence of weighted solitons. I will then present a sufficient condition of existence of weighted cscK metrics\, in line with the J-flow approach of Song-Weinkove. Then I will focus on the semisimple principal fibration cosntruction\, a construction of varieties from a principal torus bundle and a fiber. The link with weighted Kähler geometry is that\, under assumptions on the principal bundle\, the Kähler geometry of the total space reduces to the weighted Kähler geometry of the fiber.
URL:https://ccg.ibs.re.kr/event/2025-0407/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250409T140000
DTEND;TZID=Asia/Seoul:20250409T150000
DTSTAMP:20260415T203308
CREATED:20250318T132054Z
LAST-MODIFIED:20250318T132212Z
UID:3711-1744207200-1744210800@ccg.ibs.re.kr
SUMMARY:Thibaut Delcroix\, Weighted Kähler geometry and semisimple principal fibrations (Lecture IV)
DESCRIPTION:    Speaker\n\n\nThibaut Delcroix\nUniversité de Montpellier\n\n\n\n\n\n\nIn Kähler geometry\, especially in the questions of existence of canonical Kähler metrics\, the volume form ωn associated with a Kähler form ω plays a central role. In weighted Kähler geometry\, we consider a Kähler manifold X equipped with a Hamiltonian action of a torus T\, a moment map μ and associated moment polytope Δ=μ(X). We fix a weight function v:Δ → (0\,+∞)\, then replace the volume form ωn by v ◦ μ ωn. One can then define new canonical Kähler metrics: weighted solitons and weighted cscK metrics (introduced by Lahdili)\, which include most classical canonical Kähler metrics. \nI will first introduce this weighted setting\, then the (analytic) weighted delta invariant\, a number that encodes the existence of weighted solitons. I will then present a sufficient condition of existence of weighted cscK metrics\, in line with the J-flow approach of Song-Weinkove. Then I will focus on the semisimple principal fibration cosntruction\, a construction of varieties from a principal torus bundle and a fiber. The link with weighted Kähler geometry is that\, under assumptions on the principal bundle\, the Kähler geometry of the total space reduces to the weighted Kähler geometry of the fiber.
URL:https://ccg.ibs.re.kr/event/2025-0409/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250416T160000
DTEND;TZID=Asia/Seoul:20250416T170000
DTSTAMP:20260415T203308
CREATED:20250410T074749Z
LAST-MODIFIED:20250410T074749Z
UID:3759-1744819200-1744822800@ccg.ibs.re.kr
SUMMARY:Long Li\, Plurisubharmonic functions and Sasaki geometry
DESCRIPTION:    Speaker\n\n\nLong Li\nShanghaiTech University\n\n\n\n\n\n\nIn this talk\, we will discuss the recent progress on the zero mass conjecture for plurisubharmoinc functions\, raised by Guedj and Rashkovskii. For a local plurisubharmonic function with an isolated singularity at the origin\, the conjecture states that the zero Lelong number (at the singularity) implies the zero residual Monge-Ampere mass at the same point. We confirm this conjecture under the circular symmetry condition\, with the aid from Sasaki geometry. Furthermore\, we will also apply our technique to more general plurisubharmonic functions in certain cases.
URL:https://ccg.ibs.re.kr/event/2025-0416/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250418T110000
DTEND;TZID=Asia/Seoul:20250418T120000
DTSTAMP:20260415T203308
CREATED:20250314T060803Z
LAST-MODIFIED:20250413T225322Z
UID:3698-1744974000-1744977600@ccg.ibs.re.kr
SUMMARY:Jie Liu\, Symplectic singularities arising from cotangent bundles
DESCRIPTION:    Speaker\n\n\nJie Liu\nAMSS\n\n\n\n\n\n\nI’ll report joint works with Baohua Fu (AMSS)\, in which we investigate symplectic singularities arising from the affinization of the cotangent bundle of a smooth variety.
URL:https://ccg.ibs.re.kr/event/2025-0418/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250421
DTEND;VALUE=DATE:20250425
DTSTAMP:20260415T203308
CREATED:20241022T235228Z
LAST-MODIFIED:20250429T025235Z
UID:3456-1745193600-1745539199@ccg.ibs.re.kr
SUMMARY:Progress in Complex Geometry
DESCRIPTION:The goal of the workshop is to INTRODUCE some of the most interesting recent developments in complex geometry to (young) people working in areas related to complex geometry. For this purpose\, the speakers will try to make the talks understandable to broad audience. \nInvited Speakers\n2-hours lectures \nBin Guo (Rutgers U.)\nShigeharu Takayama (U. Tokyo)\nDavid Witt Nyström (Chalmers U.) \n1-hour talks \nDamian Brotbek (U. Lorraine)\nYoung-Jun Choi (Pusan National U.)\nJie Liu (AMSS\, CAS)\nShinichi Matsumura (Tohoku U.)\nDror Varolin (Stony Brook U.)\nJuanyong Wang (AMSS\, CAS)\nMing Xiao (U.C. San Diego)\nJunyi Xie (Peking U.) \nAbstracts\nPDF file \nSchedule\nMonday (21st) \nChair: Jun-Muk Hwang\n10:00-11:00 Witt Nyström\n11:30-12:30 Witt Nyström \nChair: Yongnam Lee\n15:00-16:00 Liu\n16:30-17:30 Matsumura \nTuesday (22nd) \nChair: Ngoc Cuong Nguyen\n10:00-11:00 Guo\n11:30-12:30 Guo \nChair: Sungyeon Kim\n15:00-16:00 Xie\n16:30-17:30 Xiao\n18:00-20:00 Banquet \nWednesday (23rd) \nChair: DongSeon Hwang\n10:00-11:00 Takayama\n11:30-12:30 Takayama \nChair: Thibaut Delcroix\n15:00-16:00 Choi\n16:30-17:30 Wang \nThursday (24th) \nChair: Mihai Paun\n10:00-11:00 Brotbek\n11:30-12:30 Varolin \nOrganizers\nJun-Muk Hwang (IBS CCG)\nMihai Paun (Bayreuth) \nVenue\nB109\, IBS\, Daejeon\, Korea \nRegistration\nPlease submit Google form by April 6. \nMore Information\n• How to get to IBS-CCG
URL:https://ccg.ibs.re.kr/event/2025-0421-0424/
LOCATION:B109\, IBS\, Korea\, Republic of
CATEGORIES:Conferences and Workshops
ATTACH;FMTTYPE=image/jpeg:https://ccg.ibs.re.kr/wp-content/uploads/2025/04/2025_Apr_Group-photo-wide_300-scaled.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250507T160000
DTEND;TZID=Asia/Seoul:20250507T170000
DTSTAMP:20260415T203308
CREATED:20250429T025718Z
LAST-MODIFIED:20250502T110417Z
UID:3796-1746633600-1746637200@ccg.ibs.re.kr
SUMMARY:Ilya Kossovskiy\, Divergence in CR Geometry
DESCRIPTION:    Speaker\n\n\nIlya Kossovskiy\nSUSTech\n\n\n\n\n\n\nIn this lecture\, I will outline convergence and divergence phenomena for mappings of CR submanifolds in complex space. Possible applications for mappings of more general geometric structures will be also concerned.
URL:https://ccg.ibs.re.kr/event/2025-0507/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250508T163000
DTEND;TZID=Asia/Seoul:20250508T173000
DTSTAMP:20260415T203308
CREATED:20250404T011656Z
LAST-MODIFIED:20250404T011656Z
UID:3746-1746721800-1746725400@ccg.ibs.re.kr
SUMMARY:Meng Chen\, The Noether inequality for algebraic threefolds
DESCRIPTION:    Speaker\n\n\nMeng Chen\nFudan University\n\n\n\n\n\n\nIn this talk\, I will present a complete proof for the following theorem: the inequality K3  ≥ 4/3 pg-10/3 holds for all 3-folds of general type.
URL:https://ccg.ibs.re.kr/event/2025-0508/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250514T110000
DTEND;TZID=Asia/Seoul:20250514T120000
DTSTAMP:20260415T203308
CREATED:20250404T011824Z
LAST-MODIFIED:20250404T011824Z
UID:3748-1747220400-1747224000@ccg.ibs.re.kr
SUMMARY:Meng Chen\, On the classification of some 3-folds with small positive canonical volumes
DESCRIPTION:    Speaker\n\n\nMeng Chen\nFudan University\n\n\n\n\n\n\nIn this lecture\, I will report some new progress in studying moduli spaces of algebraic 3-folds with very small canonical volume.
URL:https://ccg.ibs.re.kr/event/2025-0514/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250519T110000
DTEND;TZID=Asia/Seoul:20250519T120000
DTSTAMP:20260415T203308
CREATED:20250508T092009Z
LAST-MODIFIED:20250508T092009Z
UID:3807-1747652400-1747656000@ccg.ibs.re.kr
SUMMARY:JongHae Keum\, Fake quadric surfaces
DESCRIPTION:    Speaker\n\n\nJongHae Keum\nKIAS\n\n\n\n\n\n\nA smooth projective complex surface S is called a Q-homology quadric if it has the same Betti numbers as the smooth quadric surface. Let S be a Q-homology quadric. Then its cohomology lattice is of rank 2\, (even or odd) unimodular. By the classification of surfaces\, S is either rational or of general type. In the latter case\, S is called a fake Q-homology quadric (fake quadric\, in short). There is an unsolved question raised by Hirzebruch: does there exist a surface of general type which is homeomorphic to the smooth quadric surface? I will report recent progress on these surfaces.
URL:https://ccg.ibs.re.kr/event/2025-0519/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250520T110000
DTEND;TZID=Asia/Seoul:20250520T120000
DTSTAMP:20260415T203308
CREATED:20250425T013616Z
LAST-MODIFIED:20250425T013616Z
UID:3784-1747738800-1747742400@ccg.ibs.re.kr
SUMMARY:Gian Pietro Pirola\, Asymptotic directions on the moduli space of curves
DESCRIPTION:    Speaker\n\n\nGian Pietro Pirola\nUniversity of Pavia\n\n\n\n\n\n\nWe present some computational improvements that allow us to study asymptotic lines in the tangent of the moduli space Mg of the curves of genus g. The asymptotic directions are those tangent directions that are annihilated by the second fundamental form induced by the Torelli map. We give examples of asymptotic lines for any g > 3 and we study their rank. The rank r(v) of a tangent direction at Mg is defined to be the rank of the cup product map associated to the infinitesimal deformation map\, that is the infinitesimal variation of Hodge structure in that direction. We show that if v is not zero and r(v)< (cliff(C) + 1) where cliff(C) is the Clifford index of C\, then v is not asymptotic and we study the case when r(v)= cliff(C). Finally all asymptotic directions of rank 1 are determined and a description of the rank 2 case is given. It is a joint work with Elisabetta Colombo and Paola Frediani.
URL:https://ccg.ibs.re.kr/event/2025-0520-2/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250520T160000
DTEND;TZID=Asia/Seoul:20250520T173000
DTSTAMP:20260415T203308
CREATED:20250415T070256Z
LAST-MODIFIED:20250513T025401Z
UID:3764-1747756800-1747762200@ccg.ibs.re.kr
SUMMARY:Benjamin McMillan\, Secondary Characteristic classes and Chern-Weil theory of (Haefliger) singular foliations I
DESCRIPTION:    Speaker\n\n\nBenjamin McMillan\nIBS CCG\n\n\n\n\n\n\nFoliations have a theory of characteristic classes that is much like that of vector bundles\, but with notable differences. Some of the characteristic classes of a foliation come from its induced normal bundle\, but there are additional secondary classes that depend on more detailed information about the foliation. Just as with vector bundles\, one can obtain the characteristic classes using either a universal space or the Chern-Weil construction (in case the foliation is regular). \nIn these talks I will explain the general theory\, and how the Chern-Weil construction can often be made to work even for singular foliations.
URL:https://ccg.ibs.re.kr/event/2025-0520/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250521T160000
DTEND;TZID=Asia/Seoul:20250521T173000
DTSTAMP:20260415T203308
CREATED:20250415T070417Z
LAST-MODIFIED:20250513T025423Z
UID:3767-1747843200-1747848600@ccg.ibs.re.kr
SUMMARY:Benjamin McMillan\, Secondary Characteristic classes and Chern-Weil theory of (Haefliger) singular foliations II
DESCRIPTION:    Speaker\n\n\nBenjamin McMillan\nIBS CCG\n\n\n\n\n\n\nFoliations have a theory of characteristic classes that is much like that of vector bundles\, but with notable differences. Some of the characteristic classes of a foliation come from its induced normal bundle\, but there are additional secondary classes that depend on more detailed information about the foliation. Just as with vector bundles\, one can obtain the characteristic classes using either a universal space or the Chern-Weil construction (in case the foliation is regular). \nIn these talks I will explain the general theory\, and how the Chern-Weil construction can often be made to work even for singular foliations.
URL:https://ccg.ibs.re.kr/event/2025-0521/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250522T110000
DTEND;TZID=Asia/Seoul:20250522T120000
DTSTAMP:20260415T203308
CREATED:20250415T070509Z
LAST-MODIFIED:20250513T025909Z
UID:3769-1747911600-1747915200@ccg.ibs.re.kr
SUMMARY:Benjamin McMillan\, Secondary Characteristic classes and Chern-Weil theory of (Haefliger) singular foliations III
DESCRIPTION:    Speaker\n\n\nBenjamin McMillan\nIBS CCG\n\n\n\n\n\n\nFoliations have a theory of characteristic classes that is much like that of vector bundles\, but with notable differences. Some of the characteristic classes of a foliation come from its induced normal bundle\, but there are additional secondary classes that depend on more detailed information about the foliation. Just as with vector bundles\, one can obtain the characteristic classes using either a universal space or the Chern-Weil construction (in case the foliation is regular). \nIn these talks I will explain the general theory\, and how the Chern-Weil construction can often be made to work even for singular foliations.
URL:https://ccg.ibs.re.kr/event/2025-0522-1/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250522T140000
DTEND;TZID=Asia/Seoul:20250522T150000
DTSTAMP:20260415T203308
CREATED:20250415T070802Z
LAST-MODIFIED:20250513T052302Z
UID:3773-1747922400-1747926000@ccg.ibs.re.kr
SUMMARY:Sanghyeon Lee\, Vafa-Witten invariants on elliptic surfaces and moduli space of quasisections
DESCRIPTION:    Speaker\n\n\nSanghyeon Lee\nAjou University\n\n\n\n\n\n\nFor a threefold X = C x S\, D. Nesterov developed a theory of quasimaps from C to the moduli space of sheaves over S. He compared the moduli space of quasimaps and the moduli space of sheaves over the threefold X and also compared their obstruction theories. \nWhen X is a smooth fibration over C\, I will explain how to generalize Nesterov’s theory by using a notion of quasisections\, instead of quasimap\, and the correspondence between moduli space of sheaves over X and the moduli space of quasisections to the relative moduli space of sheaves. As an application\, I will explain how to compute Vafa-Witten invariants of an elliptic surface\, which is a smooth fibration over C. \nMoreover\, for the case when the elliptic surface has nodal fibers\, we will discuss how we can generalize the theory of quasisections. This is based on an ongoing project with Yaoxiong Wen.
URL:https://ccg.ibs.re.kr/event/2025-0522/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250527T163000
DTEND;TZID=Asia/Seoul:20250527T173000
DTSTAMP:20260415T203308
CREATED:20250425T013928Z
LAST-MODIFIED:20250425T013928Z
UID:3786-1748363400-1748367000@ccg.ibs.re.kr
SUMMARY:Gian Pietro Pirola\, Sections of the Jacobian bundles of plane curves and applications
DESCRIPTION:    Speaker\n\n\nGian Pietro Pirola\nUniversity of Pavia\n\n\n\n\n\n\nWe study normal functions (sections of the Jacobian bundle) defined on the moduli space of pointed plane curves. Using the infinitesimal Griffiths invariant (refined by M. Green and C. Voisin) we show that a normal function with nontrivial but sufficiently “small” support cannot be “locally constant”. As an application\, we give a variational proof of the following result of Zu: \nTheorem: If C is a very general plane curve of degree d and C’ is any plane curve of degree d’\, then the cardinality i(C\, C’) of the intersection between C and C’ is > d-3. \nWe also show that if d > 3 and i(C\, C’) = d-2 then d’ = 1 and C’ is a bitangent or a flex line. For d = 4 this is a result of Chen\, Rield and Yeong. This is a joint work with Lorenzo Fassina.
URL:https://ccg.ibs.re.kr/event/2025-0527/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250608
DTEND;VALUE=DATE:20250615
DTSTAMP:20260415T203308
CREATED:20250616T073356Z
LAST-MODIFIED:20250616T074157Z
UID:3851-1749340800-1749945599@ccg.ibs.re.kr
SUMMARY:Han-Bom Moon (Fordham University)
DESCRIPTION:Han-Bom Moon\nVisitor (2025.6.8-2025.6.14) from Fordham University
URL:https://ccg.ibs.re.kr/event/250608-250614/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250609T163000
DTEND;TZID=Asia/Seoul:20250609T173000
DTSTAMP:20260415T203308
CREATED:20250420T041641Z
LAST-MODIFIED:20250420T041753Z
UID:3781-1749486600-1749490200@ccg.ibs.re.kr
SUMMARY:Han-Bom Moon\, Ulrich bundles on intersections of quadrics
DESCRIPTION:    Speaker\n\n\nHan-Bom Moon\nFordham University\n\n\n\n\n\n\nAn Ulrich bundle is a vector bundle with very strong cohomology vanishing conditions. Eisenbud and Schreyer conjectured that every smooth projective variety possesses an Ulrich bundle. Despite many results on low dimensional varieties and special varieties\, the general existence is unknown. In this talk\, I will describe recent work in progress with Kyoung-Seog Lee and Jiwan Jeong on the construction of Ulrich bundles on an intersection of quadrics.
URL:https://ccg.ibs.re.kr/event/2025-0609/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250623
DTEND;VALUE=DATE:20250706
DTSTAMP:20260415T203308
CREATED:20250616T073537Z
LAST-MODIFIED:20250616T074129Z
UID:3853-1750636800-1751759999@ccg.ibs.re.kr
SUMMARY:Patrick Brosnan (University of Maryland)
DESCRIPTION:Patrick Brosnan\nVisitor (2025.6.23-2025.7.5) from University of Maryland
URL:https://ccg.ibs.re.kr/event/250623-250705/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250624T163000
DTEND;TZID=Asia/Seoul:20250624T173000
DTSTAMP:20260415T203308
CREATED:20250521T065127Z
LAST-MODIFIED:20250521T065607Z
UID:3820-1750782600-1750786200@ccg.ibs.re.kr
SUMMARY:Sung Gi Park\, Hodge symmetries of singular varieties
DESCRIPTION:    Speaker\n\n\nSung Gi Park\nPrinceton U. / IAS\n\n\n\n\n\n\nThe Hodge diamond of a smooth projective complex variety exhibits fundamental symmetries\, arising from Poincaré duality and the purity of Hodge structures. In the case of a singular projective variety\, the complexity of the singularities is closely related to the symmetries of the analogous Hodge-Du Bois diamond. For example\, the failure of the first nontrivial Poincaré duality is reflected in the defect of factoriality. Based on joint work with Mihnea Popa\, I will discuss how local and global conditions on singularities influence the topology of algebraic varieties.
URL:https://ccg.ibs.re.kr/event/2025-0624/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20250625
DTEND;VALUE=DATE:20250706
DTSTAMP:20260415T203308
CREATED:20250616T073703Z
LAST-MODIFIED:20250616T074057Z
UID:3855-1750809600-1751759999@ccg.ibs.re.kr
SUMMARY:Alex Abreu (Universidade Federal Fluminense)
DESCRIPTION:Alex Abreu\nVisitor (2025.6.25-2025.7.5) from Universidade Federal Fluminense
URL:https://ccg.ibs.re.kr/event/250625-250705/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250626T163000
DTEND;TZID=Asia/Seoul:20250626T173000
DTSTAMP:20260415T203308
CREATED:20250601T044122Z
LAST-MODIFIED:20250601T044122Z
UID:3844-1750955400-1750959000@ccg.ibs.re.kr
SUMMARY:Yoosik Kim\, Disk Counting via GIT Quotients
DESCRIPTION:    Speaker\n\n\nYoosik Kim\nPusan National University\n\n\n\n\n\n\nAccording to the Kempf–Ness theorem\, the GIT quotient is equivalent to the symplectic reduction. Using this correspondence\, we explain how to relate the counting of holomorphic disks between a symplectic manifold equipped with a Hamiltonian group action and its symplectic reduction. As an application\, we derive the disk potential function for weight varieties obtained as quotients by the maximal torus of partial flag varieties. We also demonstrate how the disk counting depends on the choice of stability conditions.
URL:https://ccg.ibs.re.kr/event/2025-0626/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250627T110000
DTEND;TZID=Asia/Seoul:20250627T120000
DTSTAMP:20260415T203308
CREATED:20250402T105322Z
LAST-MODIFIED:20250616T073823Z
UID:3739-1751022000-1751025600@ccg.ibs.re.kr
SUMMARY:Alex Abreu\, On the Torelli Theorem for graphs and stable curves
DESCRIPTION:    Speaker\n\n\nAlex Abreu\nUniversidade Federal Fluminense\n\n\n\n\n\n\nThe classical Torelli theorem states that a smooth curve can be recovered from its polarized Jacobian. In this talk\, we will discuss the extensions of this theorem to stable curves and their dual graphs\, as well as its dependence on the concept of compactified Jacobians. First\, we will recall Caporaso and Viviani’s theorem\, which characterizes when two stable curves have the same Caporaso’s compactified Jacobian. Then we will discuss Torelli’s theorem via fine compactified Jacobians. This is based on an ongoing joint work with Marco Pacini and Nicola Pagani.
URL:https://ccg.ibs.re.kr/event/2025-0627/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
END:VCALENDAR