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X-WR-CALNAME:Center for Complex Geometry
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X-WR-CALDESC:Events for Center for Complex Geometry
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TZID:Asia/Seoul
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TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20220101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230726T100000
DTEND;TZID=Asia/Seoul:20230726T121500
DTSTAMP:20260416T081909
CREATED:20230615T085501Z
LAST-MODIFIED:20230615T085501Z
UID:2321-1690365600-1690373700@ccg.ibs.re.kr
SUMMARY:Chang-Yeon Chough\, Introduction to algebraic stacks\, VII\, VIII
DESCRIPTION:    Speaker\n\n\nChang-Yeon Chough\nSogang Univ.\n\n\n\n\n\n\nThis is an 8 hours long lecture series on algebraic stacks\, which have become an important part of algebraic geometry (for example\, in the study of moduli spaces) since Deligne and Mumford established the foundation of the theory of stacks. This crash course will be following roughly “Algebraic Spaces and Stacks” by Martin Olsson. Our main goal is to set up a foundation for the theory of algebraic stacks\, so that the attendees would be able to use it in their own research in the future.
URL:https://ccg.ibs.re.kr/event/2023-07-26/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230725T150000
DTEND;TZID=Asia/Seoul:20230725T173000
DTSTAMP:20260416T081909
CREATED:20230615T085406Z
LAST-MODIFIED:20230712T131050Z
UID:2319-1690297200-1690306200@ccg.ibs.re.kr
SUMMARY:Chang-Yeon Chough\, Introduction to algebraic stacks\, V\, VI
DESCRIPTION:    Speaker\n\n\nChang-Yeon Chough\nSogang Univ.\n\n\n\n\n\n\nThis is an 8 hours long lecture series on algebraic stacks\, which have become an important part of algebraic geometry (for example\, in the study of moduli spaces) since Deligne and Mumford established the foundation of the theory of stacks. This crash course will be following roughly “Algebraic Spaces and Stacks” by Martin Olsson. Our main goal is to set up a foundation for the theory of algebraic stacks\, so that the attendees would be able to use it in their own research in the future.
URL:https://ccg.ibs.re.kr/event/2023-07-25-1500-1730/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230725T110000
DTEND;TZID=Asia/Seoul:20230725T120000
DTSTAMP:20260416T081909
CREATED:20230712T131020Z
LAST-MODIFIED:20230716T052748Z
UID:2356-1690282800-1690286400@ccg.ibs.re.kr
SUMMARY:Patrick Brosnan\, How Markman Saves the Hodge Conjecture (for Weil Type Abelian Fourfolds) from Kontsevich\, II
DESCRIPTION:    Speaker\n\n\nPatrick Brosnan\nUniversity of Maryland\n\n\n\n\n\n\nI’ll explain what I know about two very interesting pieces of work: \n(1) Markman’s proof of the Hodge conjecture for Weil type abelian fourfolds of discriminant 1. \n(2) Kontsevich’s tropical approach to looking for counterexamples to the Hodge conjecture for Weil type abelian varieties. \nThen I’ll explain a simple observation of mine\, which implies that Kontsevich’s approach cannot work for abelian fourfolds of any discriminant. \nI’ll start out by explaining the statement of (1) precisely along with the geometric input that is required in (2). Then I’ll formulate my observation\, which is really about why the discriminant determines what types of degenerations an abelian fourfold of Weil type can have. Along the way\, I’ll take the opportunity to say a little bit about Markman’s proof of (1).
URL:https://ccg.ibs.re.kr/event/2023-07-25-1100-1200/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230720T110000
DTEND;TZID=Asia/Seoul:20230720T120000
DTSTAMP:20260416T081909
CREATED:20230712T130908Z
LAST-MODIFIED:20230716T052735Z
UID:2354-1689850800-1689854400@ccg.ibs.re.kr
SUMMARY:Patrick Brosnan\, How Markman Saves the Hodge Conjecture (for Weil Type Abelian Fourfolds) from Kontsevich\, I
DESCRIPTION:    Speaker\n\n\nPatrick Brosnan\nUniversity of Maryland\n\n\n\n\n\n\nI’ll explain what I know about two very interesting pieces of work: \n(1) Markman’s proof of the Hodge conjecture for Weil type abelian fourfolds of discriminant 1. \n(2) Kontsevich’s tropical approach to looking for counterexamples to the Hodge conjecture for Weil type abelian varieties. \nThen I’ll explain a simple observation of mine\, which implies that Kontsevich’s approach cannot work for abelian fourfolds of any discriminant. \nI’ll start out by explaining the statement of (1) precisely along with the geometric input that is required in (2). Then I’ll formulate my observation\, which is really about why the discriminant determines what types of degenerations an abelian fourfold of Weil type can have. Along the way\, I’ll take the opportunity to say a little bit about Markman’s proof of (1).
URL:https://ccg.ibs.re.kr/event/2023-07-20/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230719T100000
DTEND;TZID=Asia/Seoul:20230719T121500
DTSTAMP:20260416T081909
CREATED:20230615T085304Z
LAST-MODIFIED:20230615T085519Z
UID:2317-1689760800-1689768900@ccg.ibs.re.kr
SUMMARY:Chang-Yeon Chough\, Introduction to algebraic stacks\, III\, IV
DESCRIPTION:    Speaker\n\n\nChang-Yeon Chough\nSogang Univ.\n\n\n\n\n\n\nThis is an 8 hours long lecture series on algebraic stacks\, which have become an important part of algebraic geometry (for example\, in the study of moduli spaces) since Deligne and Mumford established the foundation of the theory of stacks. This crash course will be following roughly “Algebraic Spaces and Stacks” by Martin Olsson. Our main goal is to set up a foundation for the theory of algebraic stacks\, so that the attendees would be able to use it in their own research in the future.
URL:https://ccg.ibs.re.kr/event/2023-07-19/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230718T150000
DTEND;TZID=Asia/Seoul:20230718T173000
DTSTAMP:20260416T081909
CREATED:20230615T085143Z
LAST-MODIFIED:20230615T085546Z
UID:2315-1689692400-1689701400@ccg.ibs.re.kr
SUMMARY:Chang-Yeon Chough\, Introduction to algebraic stacks\, I\, II
DESCRIPTION:    Speaker\n\n\nChang-Yeon Chough\nSogang Univ.\n\n\n\n\n\n\nThis is an 8 hours long lecture series on algebraic stacks\, which have become an important part of algebraic geometry (for example\, in the study of moduli spaces) since Deligne and Mumford established the foundation of the theory of stacks. This crash course will be following roughly “Algebraic Spaces and Stacks” by Martin Olsson. Our main goal is to set up a foundation for the theory of algebraic stacks\, so that the attendees would be able to use it in their own research in the future.
URL:https://ccg.ibs.re.kr/event/2023-07-18/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230711T160000
DTEND;TZID=Asia/Seoul:20230711T170000
DTSTAMP:20260416T081909
CREATED:20230621T041523Z
LAST-MODIFIED:20230621T041523Z
UID:2343-1689091200-1689094800@ccg.ibs.re.kr
SUMMARY:Qifeng Li\, Rigidity of Projective Symmetric Manifolds of Picard Number 1 Associated to Composition Algebras
DESCRIPTION:    Speaker\n\n\nQifeng Li\nShandong University\n\n\n\n\n\n\nTo each complex composition algebra A\, there associates a projective symmetric manifold X(A) of Picard number 1. The vareity X(A) is closed related with Freudenthal’s Magic Square\, which is a square starting from the adjiont varieties of F4\, E6\, E7 and E8. In a recent joint work with Yifei Chen and Baohua Fu\, we obtain the deformation rigidity of X(A). In this talk\, we will introduce the construction of X(A) from Freudenthal’s Magic Square\, the geometric properties of them\, and finally the deformation rigidity of X(A).
URL:https://ccg.ibs.re.kr/event/2023-07-11/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230706T110000
DTEND;TZID=Asia/Seoul:20230706T120000
DTSTAMP:20260416T081909
CREATED:20230620T054046Z
LAST-MODIFIED:20230620T054046Z
UID:2340-1688641200-1688644800@ccg.ibs.re.kr
SUMMARY:Shinnosuke Okawa\, Semiorthogonal Decompositions and Relative Canonical Base Locus
DESCRIPTION:    Speaker\n\n\nShinnosuke Okawa\nOsaka University\n\n\n\n\n\n\nMotivated by the DK hypothesis\, some years ago I proved that SODs of the derived category of a smooth projective variety are strongly constrained by the base locus of the canonical linear system. In particular\, this leads to the indecomposability of the derived category of varieties whose canonical bundles are globally generated (hence minimal). In this talk I will briefly recall this work and discuss its generalization to the relative settings. The latter implies new indecomposability results\, including the case of minimal surfaces of positive irregularity. This talk is based on arXiv:2304.14048.
URL:https://ccg.ibs.re.kr/event/2023-07-06/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230704T160000
DTEND;TZID=Asia/Seoul:20230704T170000
DTSTAMP:20260416T081909
CREATED:20230620T053922Z
LAST-MODIFIED:20230620T053922Z
UID:2338-1688486400-1688490000@ccg.ibs.re.kr
SUMMARY:Shinnosuke Okawa\, Moduli Space of Semiorthogonal Decompositions
DESCRIPTION:    Speaker\n\n\nShinnosuke Okawa\nOsaka University\n\n\n\n\n\n\nSemiorthogonal decomposition (SOD) is a central notion in the study of triangulated categories. In particular\, SODs of the bounded derived category of coherent sheaves of a variety (SODs of the variety\, for short) have profound relations to its geometry. In this talk I discuss the moduli functor which classifies SODs of the fibers of smooth projective morphisms. The main result is that it is an algebraic space which is locally etale over the target of the morphism. I will explain the main points of the proof\, various applications and open problems. This talk is based on the joint work arXiv:2002.03303 with Andrea Ricolfi and Pieter Belmans.
URL:https://ccg.ibs.re.kr/event/2023-07-04/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230622T110000
DTEND;TZID=Asia/Seoul:20230622T120000
DTSTAMP:20260416T081909
CREATED:20230310T045150Z
LAST-MODIFIED:20230601T124014Z
UID:2130-1687431600-1687435200@ccg.ibs.re.kr
SUMMARY:Shin-Young Kim\, Minimal Rational Curves on Complete Symmetric Varieties
DESCRIPTION:    Speaker\n\n\nShin-Young Kim\nIBS-CGP\n\n\n\n\n\n\nWe describe the families of minimal rational curves on any complete symmetric variety\, and the corresponding varieties of minimal rational tangents. In particular\, we prove that these varieties are homogeneous and that for non-exceptional irreducible wonderful varieties\, there is a unique family of minimal rational curves. We relate these results to the restricted root system of the associated symmetric space. In particular\, for certain Fano wonderful symmetric varieties\, the VMRT has two connected components. This is a joint work with M.Brion and N. Perrin.
URL:https://ccg.ibs.re.kr/event/2023-06-22/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230620T110000
DTEND;TZID=Asia/Seoul:20230620T120000
DTSTAMP:20260416T081909
CREATED:20230421T053444Z
LAST-MODIFIED:20230421T053619Z
UID:2251-1687258800-1687262400@ccg.ibs.re.kr
SUMMARY:Sung Gi Park\, Kodaira Dimension and Hyperbolicity for Smooth Families of Varieties
DESCRIPTION:    Speaker\n\n\nSung Gi Park\nHarvard University\n\n\n\n\n\n\nIn this talk\, I will discuss the behavior of positivity\, hyperbolicity\, and Kodaira dimension under smooth morphisms of complex quasi-projective manifolds. This includes a vast generalization of a classical result: a fibration from a projective surface of non-negative Kodaira dimension to a projective line has at least three singular fibers. Furthermore\, I will explain a proof of Popa’s conjecture on the superadditivity of the log Kodaira dimension over bases of dimension at most three. These theorems are applications of the main technical result\, namely the logarithmic base change theorem.
URL:https://ccg.ibs.re.kr/event/2023-06-20/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230616T153000
DTEND;TZID=Asia/Seoul:20230616T170000
DTSTAMP:20260416T081909
CREATED:20230510T091234Z
LAST-MODIFIED:20230510T091234Z
UID:2291-1686929400-1686934800@ccg.ibs.re.kr
SUMMARY:Minseong Kwon\, Introduction to Grauert Tubes
DESCRIPTION:    Speaker\n\n\nMinseong Kwon\nKAIST\n\n\n\n\n\n\nTBA
URL:https://ccg.ibs.re.kr/event/2023-06-16/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230614T153000
DTEND;TZID=Asia/Seoul:20230614T170000
DTSTAMP:20260416T081909
CREATED:20230510T091121Z
LAST-MODIFIED:20230510T091121Z
UID:2289-1686756600-1686762000@ccg.ibs.re.kr
SUMMARY:Paul-Andi Nagy\, Introduction to Feix-Kaledin Construction
DESCRIPTION:    Speaker\n\n\nPaul-Andi Nagy\nIBS-CCG\n\n\n\n\n\n\nTBA
URL:https://ccg.ibs.re.kr/event/2023-06-14/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230523T163000
DTEND;TZID=Asia/Seoul:20230523T173000
DTSTAMP:20260416T081909
CREATED:20230421T053301Z
LAST-MODIFIED:20230421T053301Z
UID:2249-1684859400-1684863000@ccg.ibs.re.kr
SUMMARY:Changho Han\, Compact Moduli of K3 Surfaces with a Given Nonsymplectic Cyclic Action
DESCRIPTION:    Speaker\n\n\nChangho Han\nUniversity of Waterloo\n\n\n\n\n\n\nTo construct a moduli space which is itself a compactification of a given moduli space\, one needs to enlarge the class of objects in consideration (e.g. adding certain singular curves to the class of smooth curves). After a brief review of the compactifications of the moduli of elliptic curves\, I will generalize into looking at various compactifications of the moduli of K3 surfaces with nonsymplectic cyclic actions\, and then discuss how those compactifications are birationally related to each other. As an application\, I will apply this framework into Kondo’s moduli space of sextic K3 surfaces with Z/3Z action. Results come from joint works (in progress) with Valery Alexeev\, Anand Deopurkar\, and Philip Engel.
URL:https://ccg.ibs.re.kr/event/2023-05-23/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20230515
DTEND;VALUE=DATE:20230520
DTSTAMP:20260416T081909
CREATED:20230127T105521Z
LAST-MODIFIED:20230525T132424Z
UID:2036-1684108800-1684540799@ccg.ibs.re.kr
SUMMARY:Workshop on Moduli\, K-stability\, Fano varieties\, and related topics
DESCRIPTION:Speakers\nArnaud Beauville (University of Nice)\nFabrizio Catanese (University of Bayreuth)\nThibaut Delcroix (University of Montpellier)\nKento Fujita (Osaka University)\nYoung-Hoon Kiem (KIAS)\nShigeru Mukai (RIMS\, Kyoto University)\nYuri Prokhorov (Steklov Mathematical Institute)\nConstantin Shramov (Steklov Mathematical Institute) \nAbstracts\nPDF File \nSchedule\nDay 1: May 15 (Monday) \n  \n\n\n\n~10:00\nRegistration\n\n\n10:00~11:00\nShigeru Mukai\nModuli of curves of genus 11\, and prime Fano 3-folds of adjacent poristic genera\, I\n\n\n11:00~11:20\nCoffee Break\n\n\n11:20~12:20\nKento Fujita\nThe Calabi problem for Fano threefolds\, I\n\n\n12:20~15:00\nLunch\n\n\n15:00~16:00\nShigeru Mukai\nModuli of curves of genus 11\, and prime Fano 3-folds of adjacent poristic genera\, II\n\n\n16:00~16:30\nCoffee Break\n\n\n16:30-17:30\nKento Fujita\nThe Calabi problem for Fano threefolds\, II\n\n\n18:00~20:00\nDinner for Speakers\n\n\n\n  \nDay 2: May 16 (Tuesday) \n\n\n\n10:00~11:00\nYuri Prokhorov\nOn the classification of singular Fano threefolds\, I\n\n\n11:00~11:20\nCoffee Break\n\n\n11:20~12:20\nConstantin Shramov\nConic bundles\, I\n\n\n12:20~15:00\nLunch\n\n\n15:00~16:00\nYuri Prokhorov\nOn the classification of singular Fano threefolds\, II\n\n\n16:00~16:30\nCoffee Break\n\n\n16:30-17:30\nConstantin Shramov\nConic bundles\, II\n\n\n\n  \nDay 3: May 17 (Wednesday) \n\n\n\n10:00~11:00\nArnaud Beauville\nSymmetric tensors on the intersection of two quadrics and Lagrangian fibration\, I\n\n\n11:00~11:20\nCoffee Break\n\n\n11:20~12:20\nThibaut Delcroix\nEffective K-stability of spherical varieties\, I\n\n\n13:20~20:00\nExcursion\n\n\n\n  \nDay 4: May 18 (Thursday) \n\n\n\n10:00~11:00\nArnaud Beauville\nSymmetric tensors on the intersection of two quadrics and Lagrangian fibration\, II\n\n\n11:00~11:20\nCoffee Break\n\n\n11:20~12:20\nThibaut Delcroix\nEffective K-stability of spherical varieties\, II\n\n\n12:20~15:00\nLunch\n\n\n15:00~16:00\nYoung-Hoon Kiem\nCounting surfaces in projective varieties\, I\n\n\n16:00~16:30\nCoffee Break\n\n\n16:30-17:30\nFabrizio Catanese\nStatus of the classification and old and new constructions for surfaces of general type with pg=q=2\, I\n\n\n18:00~20:00\nBanquet\n\n\n\n  \nDay 5: May 19 (Friday) \n\n\n\n10:00~11:00\nYoung-Hoon Kiem\nCounting surfaces in projective varieties\, II\n\n\n11:00~11:20\nCoffee Break\n\n\n11:20~12:20\nFabrizio Catanese\nStatus of the classification and old and new constructions for surfaces of general type with pg=q=2\, II\n\n\n\nOrganizers\nYongnam Lee (IBS-CCG/KAIST)\nJihun Park (IBS-CGP/POSTECH) \nMain Hotel\nLotte City Hotel Daejeon (4-30 Doryong-dong\, Yuseong-gu\, Daejeon) \nRegistration\nPlease submit Google form by April 21. \nMore Information\n• How to get to IBS-CCG\n• From Hotel to IBS\n• IBS Cafeteria (Lunch)
URL:https://ccg.ibs.re.kr/event/2023-05-15-19/
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/2023/01/Group-Photo3-1-scaled.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230511T110000
DTEND;TZID=Asia/Seoul:20230511T120000
DTSTAMP:20260416T081909
CREATED:20230426T033135Z
LAST-MODIFIED:20230426T033548Z
UID:2272-1683802800-1683806400@ccg.ibs.re.kr
SUMMARY:Shigeru Mukai\, Fano 3-folds\, Lagrangian Fibration and Leech-K3 Geometry III
DESCRIPTION:    Speaker\n\n\nShigeru Mukai\nRIMS\, Kyoto University\n\n\n\n\n\n\nPDF file
URL:https://ccg.ibs.re.kr/event/2023-05-11/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230509T150000
DTEND;TZID=Asia/Seoul:20230509T160000
DTSTAMP:20260416T081909
CREATED:20230426T033033Z
LAST-MODIFIED:20230426T033531Z
UID:2270-1683644400-1683648000@ccg.ibs.re.kr
SUMMARY:Shigeru Mukai\, Fano 3-folds\, Lagrangian Fibration and Leech-K3 Geometry II
DESCRIPTION:    Speaker\n\n\nShigeru Mukai\nRIMS\, Kyoto University\n\n\n\n\n\n\nPDF file
URL:https://ccg.ibs.re.kr/event/2023-05-09-1500-1600/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230509T110000
DTEND;TZID=Asia/Seoul:20230509T120000
DTSTAMP:20260416T081909
CREATED:20230426T032901Z
LAST-MODIFIED:20230426T033514Z
UID:2267-1683630000-1683633600@ccg.ibs.re.kr
SUMMARY:Shigeru Mukai\, Fano 3-folds\, Lagrangian Fibration and Leech-K3 Geometry I
DESCRIPTION:    Speaker\n\n\nShigeru Mukai\nRIMS\, Kyoto University\n\n\n\n\n\n\nPDF file
URL:https://ccg.ibs.re.kr/event/2023-05-09-1100-1200/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230426T160000
DTEND;TZID=Asia/Seoul:20230426T180000
DTSTAMP:20260416T081909
CREATED:20230422T055932Z
LAST-MODIFIED:20230422T055932Z
UID:2255-1682524800-1682532000@ccg.ibs.re.kr
SUMMARY:Hoseob Seo\, On L2 Extension from Singular Hypersurfaces
DESCRIPTION:    Speaker\n\n\nHoseob Seo\nIBS CCG\n\n\n\n\n\n\nIn L2 extension theorems from a singular hypersurface in a complex manifold\, important roles are played by certain measures such as the Ohsawa measure which determine when a given function can be extended. We show that the singularity of the Ohsawa measure can be identified in terms of singularity of pairs from algebraic geometry. Using this\, we give an analytic proof of the inversion of adjunction in this setting. Then these considerations enable us to compare various positive and negative results on L2 extension from singular hypersurfaces. In particular\, we generalize a recent negative result of Guan and Li which places limitations on strengthening such L2 extension by employing a less singular measure in the place of the Ohsawa measure. This is joint work with Dano Kim.
URL:https://ccg.ibs.re.kr/event/2023-04-26/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230425T110000
DTEND;TZID=Asia/Seoul:20230425T120000
DTSTAMP:20260416T081909
CREATED:20230412T042805Z
LAST-MODIFIED:20230412T042805Z
UID:2228-1682420400-1682424000@ccg.ibs.re.kr
SUMMARY:Junyan Zhao\, Moduli of Curves of Genus 6 and K-stability
DESCRIPTION:    Speaker\n\n\nJunyan Zhao\nUniversity of Illinois Chicago\n\n\n\n\n\n\nA general curve C of genus 6 can be embedded into the unique quintic del Pezzo surface X5 as a divisor of class -2KX5. This embedding is unique up to the action of the symmetric group S5. Taking a double cover of X5 branched along C yields a K3 surface Y. Thus the K-moduli spaces of the pair (X5\, C) can be studied via wall-crossing and by relating them to the Hassett-Keel program for C and the HKL program for Y. On the other hand\, X5 can be embedded in P1 × P2 as a divisor of class O(1\,2)\, under which -2KX is linearly equivalent to OX(2\,2). One can study the VGIT-moduli spaces in this setting. In this talk\, I will compare these four types of compactified moduli spaces and their different birational models given by wall-crossing.
URL:https://ccg.ibs.re.kr/event/2023-04-25/
LOCATION:on-line
CATEGORIES:Algebraic Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230419T160000
DTEND;TZID=Asia/Seoul:20230419T180000
DTSTAMP:20260416T081909
CREATED:20230413T015214Z
LAST-MODIFIED:20230413T015458Z
UID:2233-1681920000-1681927200@ccg.ibs.re.kr
SUMMARY:Jihun Yum\, Stochastic Bergman Geometry
DESCRIPTION:    Speaker\n\n\nJihun Yum\nIBS-CCG\n\n\n\n\n\n\nFor a bounded domain Ω in Cn\, let P(Ω) be the set of all (real) probability distributions on Ω. Then\, in general\, P(Ω) becomes an infinite-dimensional smooth manifold and it always admit a natural Riemannian pseudo-metric\, called the Fisher information metric\, on P(Ω). Information geometry studies a finite-dimensional submanifold M\, which is called a statistical model\, in P(Ω) using geometric concepts such as Riemannian metric\, distance\, connection\, and curvature\, to better understand the properties of statistical models M and provide insights into the behavior of learning algorithms and optimization methods. \nIn this talk\, we first introduce a map Φ : Ω → P(Ω) and prove that the pull-back of the Fisher information metric on P(Ω) is exactly same as the Bergman metric of Ω. This map provides a completely new perspective that allows us to view Bergman geometry from a stochastical viewpoint. We will discuss the following 4 things. \n1. The relation between Φ and the Kobayashi map ι : Ω → CP∞. \n2. A Stochastic formula for the holomorphic sectional curvature of the Bergman metric. \n3. A Stochastic condition for injectivity of a proper holomorphic surjective map between two bounded domains. \n4. The central limit theorem on Ω. \nThis is a joint work with Gunhee Cho at UC Santa Barbara University.
URL:https://ccg.ibs.re.kr/event/2023-04-19/
LOCATION:B266\, IBS\, Korea\, Republic of
CATEGORIES:Several Complex Variables Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230406T110000
DTEND;TZID=Asia/Seoul:20230406T120000
DTSTAMP:20260416T081909
CREATED:20230310T045023Z
LAST-MODIFIED:20230327T014355Z
UID:2128-1680778800-1680782400@ccg.ibs.re.kr
SUMMARY:Donggun Lee\, Birational Geometry of Generalized Hessenberg Varieties and the Generalized Shareshian-Wachs Conjecture
DESCRIPTION:    Speaker\n\n\nDonggun Lee\nIBS-CCG\n\n\n\n\n\n\nHessenberg varieties are subvarieties of flag varieties with interesting properties in both algebro-geometric and combinatorial perspectives. The Shareshian-Wachs conjecture connects their cohomology with the chromatic quasi-symmetric functions of the associated graphs\, which are refinements of the chromatic polynomials. In this talk\, we introduce generalized Hessenberg varieties and study their birational geometry via blowups. As a result\, natural maps from Hessenberg varieties to projective spaces or the permutohedral varieties are decomposed into explicit blowups and projective bundle maps. As a byproduct\, we also provide an elementary proof of the Shareshian-Wachs conjecture and its natural generalization. This is joint work with Prof. Young-Hoon Kiem.
URL:https://ccg.ibs.re.kr/event/2023-04-06/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230330T110000
DTEND;TZID=Asia/Seoul:20230330T120000
DTSTAMP:20260416T081909
CREATED:20230214T085114Z
LAST-MODIFIED:20230306T010918Z
UID:2086-1680174000-1680177600@ccg.ibs.re.kr
SUMMARY:Insong Choe\, Subsheaves of Maximal Rank in a Symplectic and Orthogonal Bundle over a Curve
DESCRIPTION:    Speaker\n\n\nInsong Choe\nKunkuk University\n\n\n\n\n\n\nWe first review the known results on the Quot schemes on a smooth algebraic curve. Next we explain how they can be generalized to the Lagrangian Quot scheme\, which parametrizes Lagrangian subsheaves on a symplectic vector bundle. Also we discuss the parallel results for orthogonal bundles. This will be an overview of the findings over the past 15 years in collaboration with George H. Hitching and D. Cheong.
URL:https://ccg.ibs.re.kr/event/2023-03-30/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230309T110000
DTEND;TZID=Asia/Seoul:20230309T120000
DTSTAMP:20260416T081909
CREATED:20230214T024155Z
LAST-MODIFIED:20230214T024155Z
UID:2083-1678359600-1678363200@ccg.ibs.re.kr
SUMMARY:Donghoon Jang\, Circle Actions on Almost Complex Manifolds with Isolated Fixed Points
DESCRIPTION:     Speaker\n\n\nDonghoon Jang\nPusan National University\n\n\n\n\n\n\nWe briefly review group actions on manifolds and equivariant cohomology\, which is cohomology of a manifold with a group action. We review classification results for circle actions on various types of manifolds in low dimensions. An almost complex manifold is a manifold with a complex structure on its tangent bundle; every complex or symplectic manifold is almost complex. For an action of the circle group on a compact almost complex manifold that has isolated fixed points\, we study its properties and discuss the classification when the number of fixed points is small.
URL:https://ccg.ibs.re.kr/event/2023-03-09/
LOCATION:B236-1\, IBS\, Korea\, Republic of
CATEGORIES:Complex Geometry Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230302T110000
DTEND;TZID=Asia/Seoul:20230302T120000
DTSTAMP:20260416T081910
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:20260416T081910
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:20260416T081910
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:20260416T081910
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:20260416T081910
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:20260416T081910
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
END:VCALENDAR