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).

## Minki Kim (김민기) gave a talk on the existence of a rainbow matching of size n in a family of 3n-3 matchings at the Discrete Math Seminar

On February 23, 2021, Minki Kim (김민기) from the IBS discrete mathematics group presented a talk on the existence of a rainbow matching of size n in a family of 3n-3 matchings for n>2 at the Discrete Math Seminar. The title of his talk was “Rainbow paths and rainbow matchings“.

## David Wood gave an online talk on the maximum number of copies of a fixed forest in sparse graph classes at the Virtual Discrete Math Colloquium

On February 17, 2021, David Wood from Monash University gave an online talk at the Virtual Discrete Math Colloquium on the maximum number of copies of a fixed forest in various sparse graph classes. The title of his talk was “Tree densities of sparse graph classes“.

## Martin Ziegler gave a talk on the problem of encoding metric spaces for the complexity theory at the Discrete Math Seminar

On February 16, 2021, Martin Ziegler from KAIST gave a talk at the Discrete Math Seminar on the encoding problem of metric spaces from the perspective of the complexity theory. The title of his talk was “Quantitative Coding and Complexity Theory of Continuous Data“.

## Jie Ma (马杰) gave an online talk on the maximum number of edges in a 2-connected graph with no two cycles of the same length at the Virtual Discrete Math Colloquium

On February 10, 2021, Jie Ma (马杰) from the University of Science and Technology of China gave an online talk at the Virtual Discrete Math Colloquium about the resolution of a conjecture of Boros, Caro, Füredi, and Yuster on the maximum number of edges in a 2-connected graph without two cycles of the same length. The title of his talk was “Non-repeated cycle lengths and Sidon sequences“.

## Doowon Koh (고두원) gave a talk on the approach to an upper bound of the point-sphere incidences over the finite field from the restriction estimates for cones at the Discrete Math Seminar

On February 9, 2021, Doowon Koh (고두원) from Chungbuk National University gave a talk at the Discrete Math Seminar on the restriction conjecture for the cone in four dimensions and its applications to the upper bound on the point-sphere incidences in the field field setting. The title of his talk was “On the cone restriction conjecture in four dimensions and applications in incidence geometry“.