On March 30, 2021, Casey Tompkins from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on an upper bound for the maximum number of edges in a 3-uniform hypergraph having no Berge cycles of length 4. The title of his talk was “3-uniform hypergraphs avoiding a cycle of length four“.

## Édouard Bonnet gave an online talk on ordered binary structures of bounded twin-width at the Virtual Discrete Math Colloquium

On March 24, 2021, Édouard Bonnet from the LIP, CNRS gave an online talk at the Virtual Discrete Math Colloquium on several characterizations of classes of ordered binary structures of bounded twin-width. The title of his talk was “Twin-width and ordered binary structures“.

## Hong Liu gave a talk on the extremal problem of finding nested cycles with no geometric crossing at the Discrete Math Seminar

On March 22, 2021 at the Discrete Math Seminar, Hong Liu (刘鸿) from the University of Warwick gave a talk on the extremal problem of having nested cycles with no geometric crossing by using the sublinear expanders. The title of his talk was “Nested cycles with no geometric crossing“.

## Yixin Cao gave an online talk on the algorithm for recognizing interval graphs with only four LexBFS searches at the Virtual Discrete Math Colloquium

On March 17, 2021, at the Virtual Discrete Math Colloquium, Yixin Cao (操宜新) from Hong Kong Polytechnic University gave an online talk on the recognition algorithm for interval graphs by using 4 graph searchers with an improved presentation compared to the version of Li and Wu. The title of his talk was “Recognizing (unit) interval graphs by zigzag graph searches“.

## Se-Young Yun (윤세영) presented his work on online recommendation systems at the Discrete Math Seminar

On March 16, 2021, at the Discrete Math Seminar, Se-Young Yun (윤세영) from KAIST gave a talk on a theoretical analysis of recommendation systems in an online setting, not only proving a lower bound on the regret but also providing an algorithm almost matching these lower bounds. The title of his talk was “Regret in Online Recommendation Systems“.

## Debsoumya Chakraborti presented two results on the graph saturation problems at the Discrete Math Seminar

On March 9, 2021, Debsoumya Chakraborti from the IBS Discrete Mathematics Group gave a talk explaining his two results on the graph saturation problem jointly with Po-Shen Loh. The title of his talk was “Some classical problems in graph saturation“.

## Kevin Hendrey gave a talk on the theorem on the half-integral Erdős-Posa property of cycles in a graph with edge labelling by multiple abelian groups at the Discrete Math Seminar

On March 2, 2021, Kevin Hendrey from the IBS Discrete Mathematics Group presented his recent result with Pascal Gollin, Ken-ichi Kawarabayashi, O-joung Kwon, and Sang-il Oum on the half-integral Erdős-Posa property of cycles in a graph with edge labelling by multiple abelian groups at the Discrete Math Seminar. The title of his talk was “A unified half-integral Erdős-Pósa theorem for cycles in graphs labelled by multiple abelian groups“.

## Welcome William Overman, a visiting graduate student in the IBS discrete mathematics group

The IBS discrete mathematics group welcomes William Overman, a visiting graduate student from the University of California, Irvine. He was a visiting undergraduate student two years ago. He is planning to stay with us until the end of August 2021.

## Welcome IBS Biomedical Mathematical Group (BIMAG/의생명수학그룹), a new group in the Center for Mathematical and Computational Sciences led by its CI, Prof. Jae Kyoung Kim from KAIST

On March 1, 2021, the IBS Biomedical Mathematics Group (BIMAG/의생명수학그룹) is established. It is led by its Chief Investigator, Prof. Jae Kyoung Kim (김재경) from the Department of Mathematical Sciences of KAIST. BIMAG is located on the 3rd floor of the Theory Building of the IBS HQ. As of March 2021, the IBS Center for Mathematical and Computational Sciences has three independent groups; Discrete Mathematics Group (DIMAG), Data Science Group, and Biomedical Mathematics Group (BIMAG).