## February 2023

### Laurent Stolovitch, Introduction to Normal Form Theory of Holomorphic Vector Fields 2

B236-1 IBS

Speaker Laurent Stolovitch Universite Cote d’Azur In this short lecture, I will introduce the notion of normal form and resonances. I will also explain the phenomenon of "small divisors" and give some fundamental results of holomorphic conjugacy to a normal form.

### Yoon-Joo Kim, Isotrivial Fibrations of Compact Hyper-Kähler Manifolds

B266 IBS

Speaker Yoon-Joo Kim MPI-Bonn A compact hyper-Kähler (HK) manifold and its Lagrangian fibration are higher-dimensional generalizations of a K3 surface and its elliptic fibration. A Lagrangian fibration f : X → B of a HK manifold is called isotrivial if its smooth fibers are all isomorphic to each other; this is the most

### Korea-Japan Conference in Algebraic Geometry

IBS Science Culture Center Daejeon

Speakers Yonghwa Cho (IBS-CCG) Junho Choe (KIAS) Yoshinori Gongyo (Tokyo U.) Kenta Hashizume (Kyoto U.) Sukmoon Huh (Sungkyunkwan U.) WonTae Hwang (Jeonbuk National U.) Seung-Jo Jung (Jeonbuk National U.) Yeongrak Kim (Pusan National U.) Tasuki Kinjo (IPMU, Tokyo) Tatsuki Kuwagaki (Kyoto U.) Shin-ichi Matsumura (Tohoku U.) Yosuke Matsuzawa (Osaka Metropolitan U.) Jinhyung Park (KAIST) Kenta

### Seminars on Algebraic Surfaces and Related Topics

B236-1 IBS

Schedule Feb. 27 N-resolutions Giancarlo Urzua (UC Chille) 13:30-14:20 Smooth Projective Surfaces with Pseudo-effective Tangent Bundles Guolei Zhong (IBS-CCG) 14:40-15:30 Nodal Surfaces and Cubic Discriminants Yonghwa Cho (IBS-CCG) 15:50-16:40 Lagrangian Fibration Structure on the Cotangent Bundle of a Del Pezzo Surface of Degree 4 Hosung Kim (IBS-CCG) 17:00-17:50 Dinner 18:20-20:00 Feb. 28 Deformations

### Giancarlo Urzua, N-resolutions

B236-1 IBS

Speaker Giancarlo Urzua UC Chille (This is a part of Seminars on Algebraic Surfaces and Related Topics.) I will introduce N-resolutions, which are the negative analog of the Kollár--Shepherd-Barron (1988) P-resolutions of a 2-dimensional cyclic quotient singularity. (We instead work with the corresponding M-resolutions of Benkhe-Christophersen (1994).) I will start by describing an

### Guolei Zhong, Smooth Projective Surfaces with Pseudo-effective Tangent Bundles

B236-1 IBS

Speaker Guolei Zhong IBS CCG (This is a part of Seminars on Algebraic Surfaces and Related Topics.) A vector bundle over a projective manifold is said to be pseudo-effective if the tautological line bundle of its Grothendieck projectivization is pseudo-effective. In this talk, I will show that a smooth non-uniruled projective surface S

### Yonghwa Cho, Nodal Surfaces and Cubic Discriminants

B236-1 IBS

Speaker Yonghwa Cho IBS CCG (This is a part of Seminars on Algebraic Surfaces and Related Topics.) In 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

### Hosung Kim, Lagrangian Fibration Structure on the Cotangent Bundle of a Del Pezzo Surface of Degree 4

B236-1 IBS

Speaker Hosung Kim IBS CCG (This is a part of Seminars on Algebraic Surfaces and Related Topics.) The 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,

### Dongsoo Shin, Deformations of Sandwiched Surface Singularities and the Minimal Model Program

B236-1 IBS

Speaker Dongsoo Shin Chungnam National U. (This is a part of Seminars on Algebraic Surfaces and Related Topics.) We 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,

### JongHae Keum, Mori Dream Surfaces of General Type with pg=0

B236-1 IBS

Speaker JongHae Keum KIAS (This is a part of Seminars on Algebraic Surfaces and Related Topics.) The 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).

## March 2023

### Yunhyung Cho, Monotone Lagrangian Tori in Fano Varieties

B236-1 IBS

Speaker Yunhyung Cho Sungkyunkwan University This 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

### Donghoon Jang, Circle Actions on Almost Complex Manifolds with Isolated Fixed Points

B236-1 IBS

Speaker Donghoon Jang Pusan National University We 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