Department Seminars & Colloquia

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최근의 생성모델에 관하여 스탠포드대학의 Ermon교수팀에서 NeurIPS2019, ICLR2021에 발표한 아래의 2편의 논문을 집중 리뷰하면서 SDE를 이용한 Generative Modeling의 연구동향과 발전 방향을 심층토의하게 됩니다.
2주 연속 강의 (2번째) *공지: 22일 (금) 강연이 취소되고, 25일 (월) 강연으로 변경됨.
Host: 홍영준     Contact: 설윤창 (010-8785-5872)     To be announced     2023-09-17 01:21:36
(information) "Introduction to Oriented Matroids" Series Thursdays 14:30-15:45
Host: Andreads Holmsen     English     2023-09-06 20:19:28
We will discuss certain main problems concerning group actions on 1-dimensional manifolds (the circle and the interval) and perspectives for future research.
KAI-X Distinguished lecture
Host: 백형렬     English     2023-09-08 15:21:21
최근의 생성모델에 관하여 스탠포드대학의 Ermon교수팀에서 NeurIPS2019, ICLR2021에 발표한 아래의 2편의 논문을 집중 리뷰하면서 SDE를 이용한 Generative Modeling의 연구동향과 발전 방향을 심층토의 하게 됩니다.
2주 연속 강의(1번째)
Host: 이창옥     Korean English if it is requested     2023-09-06 21:41:05
In this talk, we discuss the Neural Tangent Kernel. The NTK is closely related to the dynamics of the neural network during training via the Gradient Flow(or Gradient Descent). But, since the NTK is random at initialization and varies during training, it is quite delicate to understand the dynamics of the neural network. In relation to this issue, we introduce an interesting result: in the infinite-width limit, the NTK converge to a deterministic kernel at initialization and remains constant during training. We provide a brief proof of the result for the simplest case.
Host: 홍영준     Contact: 김규식 (T.2702)     To be announced     2023-09-11 16:14:54
(information) "Introduction to Oriented Matroids" Series Thursdays 14:30-15:45
Host: Andreads Holmsen     English     2023-09-06 20:11:46
Questions of parameter estimation – that is, finding the parameter values that allow a model to best fit some data – and parameter identifiability – that is, the uniqueness of such parameter values – are often considered in settings where experiments can be repeated to gain more certainty about the data. In this talk, however, I will consider parameter estimation and parameter identifiability in situations where data can only be collected from a single experiment or trajectory. Our motivation comes from medical settings, where data comes from a patient; such limitations in data also arise in finance, ecology, and climate, for example. In this setting, we can try to find the best parameters to fit our limited data. In this talk, I will introduce a novel, alternative goal, which we refer to as a qualitative inverse problem. The aim here is to analyze what information we can gain about a system from the available data even if we cannot estimate its parameter values precisely. I will discuss results that allow us to determine whether a given model has the ability to fit the data, whether its parameters are identifiable, the signs of model parameters, and/or the local dynamics around system fixed points, as well as how much measurement error can be tolerated without changing the conclusions of our analysis. I will consider various classes of model systems and will illustrate our latest results with the classic Lotka-Volterra system.
Host: Jaekyoung Kim     Contact: Kyushik Kim (T.2702)     English     2023-08-31 13:57:07
In the past decades, there has been considerable progress in the theory of random walks on groups acting on hyperbolic spaces. Despite the abundance of such groups, this theory is inherently not preserved under quasi-isometry. In this talk, I will present our study of random walks on groups that satisfy a certain QI-invariant property that does not refer to an action on hyperbolic spaces. Joint work with Kunal Chawla, Kasra Rafi, and Vivian He.
Host: 백형렬     English     2023-09-06 15:27:22
In this talk, we discuss some concepts that are used to study (hyperbolic) holomorphic dynamics on K3 surfaces. These concepts include Green currents, their laminations, and Green measures, which emerge as the natural choice for measuring maximal entropy. These tools effectively establish Kummer rigidity – that is, when the Green measure is absolutely continuous to the volume measure, the surface is Kummer, and the dynamics is linear. We provide an overview of the techniques employed to establish this principle and provide a glimpse into their extension within the hyperkähler context – one of the higher-dimensional analogues of K3 surfaces.
Host: 박진현     Contact: 박진현 (2734)     English     2023-07-30 20:10:14
Hénon maps were introduced by Michel Hénon as a simplified model of the Poincaré section of the Lorenz model. They are among the most studied discrete-time dynamical systems that exhibit chaotic behavior. Complex Hénon maps in any dimension have been extensively studied over the last three decades, in parallel with the development of pluripotential theory. We will present the dynamical properties of these maps such as the behavior of point orbits, variety orbits, equidistribution of periodic points and fine ergodic properties of the systems. This talk is based on the work of Bedford, Fornaess, Lyubich, Sibony, Smillie, and on recent work of the speaker in collaboration with Bianchi and Sibony.
Host: Nguyen Ngoc Cuong     Contact: Kyushik Kim (T.2702)     English     2023-08-31 13:56:00
Let V be a suvariety of a manifold M. We say that V has extension property, if any bounded holomorphic function on V extends to a holomorphic function on M with the same sup-norm. In the talk we shall explain connections between this problem and operator theory (von Neumann inequality, interpolation problem) as well as with the theory of invariant functions and metrics
Host: Nguyen Ngoc Cuong     English     2023-08-22 09:17:27
We review constructions of Manolescu’s Floer homotopy type, which gives a homotopical refinement of monopole Floer homology. Based on it, we will introduce some homology cobordism/ knot concordance invariant. Using these invariants, we provide relative versions of 10/8 inequalities for 4-manifolds with boundary or surfaces in 4-manifolds. In particular, I’ll explain Manolescu’s relative 10/8 inequality, real 10/8 inequality, and Montague’s 10/8 inequality.
Host: 박정환     English     2023-06-27 14:00:08
Let X be a semistable p-adic formal scheme. In this talk, we will discuss a prismatic description of semistable local systems on the generic fiber of X. A main new ingredient is a purity result. This is based on a joint work with Heng Du, Tong Liu, Koji Shimizu.
Host: 김완수     To be announced     2023-07-27 20:00:08
We first review fundamental concepts about Seiberg-Witten theory for closed 4-manifolds. Subsequently, we will introduce a refinement of Seiberg-Witten invariant, called Bauer—Furuta invariant. Using Bauer—Furuta invariant, I will explain how to prove Furuta’s 10/8 inequality and its variant for group actions proven by Bryan and Kato.
Host: 박정환     English     2023-06-27 13:59:19