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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
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END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230127T103000
DTEND;TZID=Asia/Seoul:20230127T113000
DTSTAMP:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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:20260417T053412
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
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221012T161500
DTEND;TZID=Asia/Seoul:20221012T171500
DTSTAMP:20260417T053412
CREATED:20220930T090135Z
LAST-MODIFIED:20220930T090135Z
UID:1820-1665591300-1665594900@ccg.ibs.re.kr
SUMMARY:Aeryeong Seo\, TBA
DESCRIPTION:     Speaker\n\n\nAeryeong Seo\nKyungpook National University\n\n\n\n\n\n\nTBA
URL:https://ccg.ibs.re.kr/event/2022-10-12-1615/
LOCATION:B266 and on-line
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221012T150000
DTEND;TZID=Asia/Seoul:20221012T160000
DTSTAMP:20260417T053412
CREATED:20220930T085835Z
LAST-MODIFIED:20220930T085918Z
UID:1818-1665586800-1665590400@ccg.ibs.re.kr
SUMMARY:Pak Tung Ho\, The Weighted Yamabe Problem
DESCRIPTION:     Speaker\n\n\nPak Tung Ho\nSogang University\n\n\n\n\n\n\nIn this talk\, I will explain what the weighted Yamabe problem is\, and mention some related results that Jinwoo Shin (KIAS) and I obtained.
URL:https://ccg.ibs.re.kr/event/2022-10-12-1500/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20221005
DTEND;VALUE=DATE:20221008
DTSTAMP:20260417T053412
CREATED:20220915T051340Z
LAST-MODIFIED:20221007T074605Z
UID:1709-1664928000-1665187199@ccg.ibs.re.kr
SUMMARY:Complex Analytic Geometry
DESCRIPTION:     Speakers\n\n\nYoung-Jun Choi (Pusan National U.)\nYoshinori Hashimoto (Osaka Metropolitan U.)\nDano Kim (Seoul National U.)\nTakayuki Koike (Osaka Metropolitan U.)\nSeungjae Lee (IBS-CCG)\nNguyen Ngoc Cuong (KAIST)\nMihai Paun (Bayreuth U.)\nMartin Sera (Kyoto U. Advanced Science)\nJihun Yum (IBS-CCG) \n\n\n     Schedule\n\n\nOct. 5 \n\n\n\n\n\nInfinitesimal extension of twisted canonical forms and applications (part 1)\nMihai Paun\n10:30-11:15 \n\n\nWeighted L2 holomorphic functions on ball fiber bundles over compact Kähler manifolds\nSeungjae Lee\n13:30-14:20 \n\n\nWeak solutions to Monge-Ampère type equations on compact Hermitian manifold with boundary\nNguyen Ngoc Cuong\n14:40-15:30 \n\n\nLimit of Bergman kernels on a tower of coverings of compact Kähler manifolds\nJihun Yum\n15:50-16:40\n\n\n\n\n\nOct. 6 \n\n\n\n\n\nInfinitesimal extension of twisted canonical forms and applications (part 2)\nMihai Paun\n10:30-11:15 \n\n\nCurvature of higher direct images\nYoung-Jun Choi\n13:30-14:20 \n\n\nSome recent results on constant scalar curvature Kähler metrics with cone singularities\nYoshinori Hashimoto\n14:40-15:30 \n\n\nProjective K3 surfaces which contain Levi-flat hypersurfaces\nTakayuki Koike\n15:50-16:40\n\n\n\n\n\nOct. 7 \n\n\n\n\n\nHermite-Einstein metrics on stable reflexive sheaves on Kaehler manifolds\nMihai Paun\n10:30-11:15 \n\n\nLelong numbers of direct images of generalized Monge-Ampère products\nMartin Sera\n13:30-14:20 \n\n\nCanonical bundle formula and degenerating families of volume forms\nDano Kim\n14:40-15:30
URL:https://ccg.ibs.re.kr/event/2022-10-5-7/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Conferences and Workshops
ATTACH;FMTTYPE=image/jpeg:https://ccg.ibs.re.kr/wp-content/uploads/2022/09/DSC00118-scaled.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220927T100000
DTEND;TZID=Asia/Seoul:20220927T110000
DTSTAMP:20260417T053412
CREATED:20220824T045238Z
LAST-MODIFIED:20220913T022712Z
UID:1683-1664272800-1664276400@ccg.ibs.re.kr
SUMMARY:Jakub Witaszek\, Quasi-F-splittings
DESCRIPTION:     Speaker\n\n\nJakub Witaszek\nPrinceton U\n\n\n\n\n\nWhat allowed for many developments in algebraic geometry and commutative algebra was a discovery of the notion of a Frobenius splitting\, which\, briefly speaking\, detects how pathological positive characteristic Fano and Calabi-Yau varieties can be. Recently\, Yobuko introduced a more general concept\, a quasi-F-splitting\, which captures much more refined arithmetic invariants. In my talk\, I will discuss on-going projects in which we develop the theory of quasi-F-splittings in the context of birational geometry and derive applications\, for example\, to liftability of singularities. This is joint work with Tatsuro Kawakami\, Hiromu Tanaka\, Teppei Takamatsu\, Fuetaro Yobuko\, and Shou Yoshikawa.
URL:https://ccg.ibs.re.kr/event/2022-09-27/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20220921
DTEND;VALUE=DATE:20221021
DTSTAMP:20260417T053412
CREATED:20220926T053633Z
LAST-MODIFIED:20220926T064625Z
UID:1760-1663718400-1666310399@ccg.ibs.re.kr
SUMMARY:Mihai Paun (University of Bayreuth)
DESCRIPTION:Mihai Paun \nVisitor (2022.9.21-2022.10.20) from University of Bayreuth\nOffice: B253
URL:https://ccg.ibs.re.kr/event/mihai-paun-220921-221020/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220915T110000
DTEND;TZID=Asia/Seoul:20220915T120000
DTSTAMP:20260417T053412
CREATED:20220822T053515Z
LAST-MODIFIED:20220828T054540Z
UID:1677-1663239600-1663243200@ccg.ibs.re.kr
SUMMARY:Benjamin McMillan\, The Range of the Killing Operator
DESCRIPTION:     Speaker\n\n\nBenjamin McMillan\nIBS-CCG\n\n\n\n\n\n\nThe Killing operator in (semi) Riemannian geometry has well understood kernel: the infinitesimal symmetries of a given metric. At the next level\, the range of the Killing operator can be interpreted as those perturbations of the metric that result from a mere change of coordinates—in contexts like general relativity\, the trivial perturbations. The range of the Killing operator\, albeit important\, has not been as well understood as its kernel. I will describe how one can use the projective nature of the Killing operator to reduce the question to that of the range of a connection on an associated bundle\, and then how one can seek to understand the range of an arbitrary connection. This process yields a fairly complete answer on locally symmetric spaces. \nBased on joint work with Federico Costanza\, Mike Eastwood\, and Thomas Leistner.
URL:https://ccg.ibs.re.kr/event/2022-09-15/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220913T100000
DTEND;TZID=Asia/Seoul:20220913T110000
DTSTAMP:20260417T053412
CREATED:20220824T045059Z
LAST-MODIFIED:20220824T071456Z
UID:1680-1663063200-1663066800@ccg.ibs.re.kr
SUMMARY:Ziquan Zhuang\, Boundedness of Singularities and Minimal Log Discrepancies of Kollár Components
DESCRIPTION:     Speaker\n\n\nZiquan Zhuang\nJohns Hopkins U\n\n\n\n\n\nSeveral years ago\, Chi Li introduced the local volume of a klt singularity in his work on K-stability. The local-global analogy between klt singularities and Fano varieties\, together with recent study in K-stability lead to the conjecture that klt singularities whose local volumes are bounded away from zero are bounded up to special degeneration. In this talk\, I will discuss some recent work on this conjecture through the minimal log discrepancies of Kollár components.
URL:https://ccg.ibs.re.kr/event/2022-09-13/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220901T110000
DTEND;TZID=Asia/Seoul:20220901T120000
DTSTAMP:20260417T053412
CREATED:20220822T053338Z
LAST-MODIFIED:20220822T065042Z
UID:1673-1662030000-1662033600@ccg.ibs.re.kr
SUMMARY:Guolei Zhong\, Dynamical Characterization of Projective Toric Varieties
DESCRIPTION:     Speaker\n\n\nGuolei Zhong\nIBS-CCG\n\n\n\n\n\nAs a fundamental building block of the equivariant minimal model program\, the rationally connected variety plays a significant role in the classification of projective varieties admitting non-isomorphic endomorphisms. Twenty years ago\, Nakayama confirmed Sato’s conjecture that\, a smooth projective rational surface is toric if and only if it admits a non-isomorphic endomorphism. In this talk\, I will survey some recent progress on a higher dimensional analogue of Nakayama’s result. This talk is based on some joint works with Jia Jia\, Sheng Meng and De-Qi Zhang.
URL:https://ccg.ibs.re.kr/event/2022-09-01/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20220815
DTEND;VALUE=DATE:20230815
DTSTAMP:20260417T053412
CREATED:20220926T052830Z
LAST-MODIFIED:20230119T042344Z
UID:1755-1660521600-1692057599@ccg.ibs.re.kr
SUMMARY:Jinhyun Park (박진현\, KAIST)
DESCRIPTION:Jinhyun Park (박진현) \nVisitor (2022.8.15-2023.8.14) from KAIST\nOffice: B248
URL:https://ccg.ibs.re.kr/event/220815-230814/
CATEGORIES:Visitors
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220614T163000
DTEND;TZID=Asia/Seoul:20220614T173000
DTSTAMP:20260417T053412
CREATED:20220613T073000Z
LAST-MODIFIED:20220607T041304Z
UID:1347-1655224200-1655227800@ccg.ibs.re.kr
SUMMARY:Luca Rizzi\, Local Systems\, Algebraic Foliations and Fibrations
DESCRIPTION:     Speaker\n\n\nLuca Rizzi\nIBS-CCG\n\n\n\n\n\nGiven a semistable fibration f : X → B I will show a correspondence between foliations on X and local systems on B. Building up on this correspondence we will find conditions that give maximal rationally connected fibrations in terms of data on the foliation. We will develop the ideas of the Castelnuovo-de Franchis theorem in the case of p-forms and show when\, under some natural conditions\, a line subbundle of the sheaf of p-forms induces the Iitaka fibration. Based on a joint work with Prof. Francesco Zucconi.
URL:https://ccg.ibs.re.kr/event/2022-06-14/
LOCATION:TBA
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220608T110000
DTEND;TZID=Asia/Seoul:20220608T120000
DTSTAMP:20260417T053412
CREATED:20220608T020000Z
LAST-MODIFIED:20220607T013422Z
UID:1294-1654686000-1654689600@ccg.ibs.re.kr
SUMMARY:Ming Xiao\, On Some Mapping Problems between Bounded Symmetric Domains
DESCRIPTION:     Speaker\n\n\nMing Xiao\nUCSD\n\n\n\n\n\nBounded symmetric domains are an important class of geometric objects in complex analysis and geometry\, which possess a high degree of symmetry. They often serve as the model cases in the study of many rigidity phenomena. In this talk\, we will discuss two mapping problems between bounded symmetric domains — proper maps and isomeric maps. We will present some recent results along these lines.
URL:https://ccg.ibs.re.kr/event/2022-06-08/
LOCATION:on-line
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220607T110000
DTEND;TZID=Asia/Seoul:20220607T120000
DTSTAMP:20260417T053412
CREATED:20220607T020000Z
LAST-MODIFIED:20220525T012126Z
UID:1226-1654599600-1654603200@ccg.ibs.re.kr
SUMMARY:Christian Schnell\, A New Approach to Degenerating Variations of Hodge Structure
DESCRIPTION:     Speaker\n\n\nChristian Schnell\nStony Brook Univ.\n\n\n\n\n\nThe theory of variations of Hodge structure has many applications in algebraic geometry. Most of these are based on the results by Schmid\, Cattani\, Kaplan\, Kashiwara\, and Kawai from the 1970s and 1980s. I will describe a new approach that proves these results — such as the Hodge norm estimates or the nilpotent orbit theorem — more easily (and that no longer requires quasi-unipotent local monodromy).
URL:https://ccg.ibs.re.kr/event/2022-06-07/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220531T164500
DTEND;TZID=Asia/Seoul:20220531T174500
DTSTAMP:20260417T053412
CREATED:20220531T074500Z
LAST-MODIFIED:20220517T005922Z
UID:1246-1654015500-1654019100@ccg.ibs.re.kr
SUMMARY:Sung Rak Choi\, On the Thresholds of Potential Pairs
DESCRIPTION:     Speaker\n\n\nSung Rak Choi\nYonsei Univ.\n\n\n\n\n\nChoi-Park first introduced and develped the notion of potential pairs. The notion was designed to control the singularities of the outcome of the ‘anticanonical’ minimal model program. In this talk\, after reviewing the properties of potnetial klt pairs\, we examine the ACC property of the potential lc thresholds. This talk is based on the joint work in progress with Sungwook Jang.
URL:https://ccg.ibs.re.kr/event/2022-05-31-1645/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220531T153000
DTEND;TZID=Asia/Seoul:20220531T163000
DTSTAMP:20260417T053412
CREATED:20220531T063000Z
LAST-MODIFIED:20220405T104109Z
UID:1244-1654011000-1654014600@ccg.ibs.re.kr
SUMMARY:Sheng Meng\, Equivariant Kähler Model for Fujiki's Class
DESCRIPTION:     Speaker\n\n\nSheng Meng\nKIAS\n\n\n\n\n\nLet X be a compact complex manifold in Fujiki’s class C\, i.e.\, admitting a big (1\,1)-class [α]. Consider Aut(X) the group of biholomorphic automorphisms and Aut[α](X) the subgroup of automorphisms preserving the class [α] via pullback. We show that X admits an Aut[α](X)-equivariant Kähler model: there is a bimeromorphic holomorphic map σ : X~ → X from a Kähler manifold X~ such that Aut[α](X) lifts holomorphically via σ.\nThere are several applications. We show that Aut[α](X) is a Lie group with only finitely many components. This generalizes an early result of Fujiki and Lieberman on the Kähler case.We also show that every torsion subgroup of Aut(X) is almost abelian\, and Aut(X) is finite if it is a torsion group.\nThis is a joint work with Jia Jia.
URL:https://ccg.ibs.re.kr/event/2022-05-31-1530/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220525T160000
DTEND;TZID=Asia/Seoul:20220525T170000
DTSTAMP:20260417T053412
CREATED:20220524T150000Z
LAST-MODIFIED:20220525T012201Z
UID:1209-1653494400-1653498000@ccg.ibs.re.kr
SUMMARY:Xu Wang\, An Explicit Estimate of the Bergman Kernel for Positive Line Bundles
DESCRIPTION:     Speaker\n\n\nXu Wang\nNTNU – Norwegian University of Science and Technology\n\n\n\n\n\n\nWe shall give an explicit estimate of the lower bound of the Bergman kernel associated to a positive line bundle. \nIn the compact Riemann surface case\, our result can be seen as an explicit version of Tian’s partial C0-estimate.
URL:https://ccg.ibs.re.kr/event/2022-05-25/
LOCATION:on-line
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220511T160000
DTEND;TZID=Asia/Seoul:20220511T170000
DTSTAMP:20260417T053412
CREATED:20220511T070000Z
LAST-MODIFIED:20220509T012741Z
UID:1250-1652284800-1652288400@ccg.ibs.re.kr
SUMMARY:Lukasz Kosinski\, Extension Property and Interpolation Problems
DESCRIPTION:     Speaker\n\n\nLukasz Kosinski\nJagiellonian University\n\n\n\n\n\nA subset V of a domain Ω has the extension property if for every holomorphic function p on V there is a bounded holomorphic function φ on Ω that agrees with p on V and whose sup-norm on Ω equals the sup-norm of p on V. Within the talk\, we shall study mutual relations between extension property and interpolations problems.
URL:https://ccg.ibs.re.kr/event/2022-05-11/
LOCATION:on-line
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220510T110000
DTEND;TZID=Asia/Seoul:20220510T120000
DTSTAMP:20260417T053412
CREATED:20220510T020000Z
LAST-MODIFIED:20220428T010609Z
UID:1224-1652180400-1652184000@ccg.ibs.re.kr
SUMMARY:Brendan Hassett\, Recent Progress and Questions on Stable Rationality
DESCRIPTION:     Speaker\n\n\nBrendan Hassett\nICERM / Brown Univ.\n\n\n\n\n\nA complex variety X is rational if its field of meromorphic functions is isomorphic to C(t1\, …\, td)\, the function field of projective space Pd. It is stably rational if X × Pm is rational for some m. Topological and complex invariants give criteria for whether varieties are stably rational but a simple characterization remains elusive. We present results for varieties admitting fibrations in conics\, quadric hypersurfaces\, and rational surfaces using techniques like decomposition of the diagonal. We close with some outstanding open problems. (joint with Kresch and Tschinkel)
URL:https://ccg.ibs.re.kr/event/2022-05-10/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220504T160000
DTEND;TZID=Asia/Seoul:20220504T170000
DTSTAMP:20260417T053412
CREATED:20220330T070000Z
LAST-MODIFIED:20220405T015749Z
UID:1150-1651680000-1651683600@ccg.ibs.re.kr
SUMMARY:Hoang-Chinh Lu\, Monge-Ampère Volumes on Compact Hermitian Manifolds
DESCRIPTION:     Speaker\n\n\nHoang-Chinh Lu\nUniversité Paris-Saclay\, Orsay\n\n\n\n\n\nWe investigate in depth the behaviour of Monge-Ampère volumes of quasi-psh functions on a given compact hermitian manifold. We prove that the property for these Monge-Ampère volumes to stay bounded away from zero or infinity is a bimeromorphic invariant. We show in particular that a conjecture of Demailly-Paun holds true if and only if such Monge-Ampère volumes stay bounded away from infinity. This is a joint work with Vincent Guedj.
URL:https://ccg.ibs.re.kr/event/2022-05-04/
LOCATION:on-line
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20220427T160000
DTEND;TZID=Asia/Seoul:20220427T170000
DTSTAMP:20260417T053412
CREATED:20220427T070000Z
LAST-MODIFIED:20220314T061453Z
UID:1154-1651075200-1651078800@ccg.ibs.re.kr
SUMMARY:Ngoc-Son Duong\, Proper Holomorphic Maps from the Complex 2-ball into the 3-dimensional Classical Domain of Type IV
DESCRIPTION:     Speaker\n\n\nNgoc-Son Duong\nUniversity of Vienna\n\n\n\n\n\nIn this talk\, we will discuss a complete classification of proper holomorphic maps from the unit ball in complex two dimensional space into the Cartan’s classical domain of type IV in complex three\ndimensional space that extend smoothly to some boundary point. This classification (which is a consequence of a classification of CR maps from the 3-sphere into the tube over the future light cone) consists of 4 algebraic maps. Among them\, two previously known maps are isometric with respect to the canonical Bergman metrics and two other maps give counterexamples to a recent conjecture of Xiao-Yuan for the case of maps from the complex 2-ball. This is a joint work with Michael Reiter.
URL:https://ccg.ibs.re.kr/event/2022-04-27/
LOCATION:on-line
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
END:VCALENDAR