On May 20, 2019, Lars Jaffke from University of Bergen, Norway presented his work on algorithmic questions regarding the b-chromatic number of graphs at the Discrete Math Seminar. The title of his talk was “A complexity dichotomy for critical values of the b-chromatic number of graphs“.

## Xin Zhang presented many results on equitable tree-k-colorings of graphs at the discrete math seminar

On May 16, 2019, Xin Zhang (张欣) from Xidian University, China discusses various results on the equitable tree-k-coloring of graphs, a problem of partitioning the vertex set of a graph into vertex-disjoint induced subgraphs having no cycles with almost same size. The title of his talk was “On equitable tree-colorings of graphs“. Xin Zhang is visiting IBS Discrete Mathematics Group from May 15 to May 19.

## Sang June Lee presented his work on strong Sidon sets at the Discrete Math Seminar

Sang June Lee (이상준) from Duksung Women’s University presented his recent work on the strong Sidon sets at the Discrete Math Seminar on May 8, 2019. The title of his talk was “On strong Sidon sets of integers“.

## Rose McCarty presented her work on the chromatic number of circle graphs at the Discrete Math Seminar

Rose McCarty from University of Waterloo presented her recent breakthrough on the polynomially 𝜒-boundedness of circle graphs at the Discrete Math Seminar on April 26, 2019 . The title of her talk was “circle graphs are polynomially chi-bounded.”

## Sang-il Oum delivered the plenary lecture at the 2019 KMS Spring Meeting.

Sang-il Oum delivered the plenary lecture at the 2019 Korean Mathematical Society Spring Meeting (대한수학회 봄 연구발표회) held at the Kangwon National University in Chuncheon on April 19-20, 2019. The title of his talk was “How to decompose a graph into a tree-like structure”.

## Jon-Lark Kim gave an introductory talk on Boolean functions with Artificial Neural Network

Jon-Lark Kim (김종락) from Sogang University presented a talk at Discrete Math Seminar on April 18, 2019. The title of his talk was “Introduction to Boolean functions with Artificial Neural Network“.

## Andreas Holmsen presented his work on an extremal problem on hypergraphs on March 12 at the discrete math seminar

Andreas Holmsen from KAIST gave a talk at Discrete Math Seminar on March 12, 2019 under the title “large cliques in hypergraphs with forbidden substructures.” His work extended a result of extremal graph theory due to Gyárfás, Hubenko, and Solymosi, answering a question of Erdős to hypergraphs and has interesting consequences in topological combinatorics and abstract convexity.

## DIMAG had its first workshop “2019-1 IBS Workshop on Graph Theory”

DIMAG had its first workshop “2019-1 IBS Workshop on Graph Theory” on February 11 and 12, 2019. There were 6 invited talks — Jeong Han Kim (KIAS), Cory T. Palmer (Univ. of Montana), Martin Balko (Charles Univ.), Dong Yeap Kang (KAIST), Boram Park (Ajou Univ.), and Dániel Gerbner (Alfréd Rényi Institute of Mathematics). We would like to thank all speakers and participants.

The talks are recorded but due to technical problems, only four talks are available online.

## Seog-Jin Kim presented his work on signed colouring and list colouring of k-chromatic graphs on January 28

Seog-Jin Kim from Konkuk University presented a talk at Discrete Math Seminar on January 28, 2019. The title of his talk was “Signed colouring and list colouring of k-chromatic graphs.”

## 2019-1 IBS Workshop on Graph Theory (Feb. 11-12, 2019). Registration due: Jan. 28

The Discrete Mathematics Group (DIMAG) at the Institute for Basic Science (IBS) will have its first workshop in Feb. 11-12, 2019. If you want to participate, then please register by January 28 on the website. We plan to provide accommodation for speakers and selected participants requested during the online registration.

- Title: 2019-1 IBS Workshop on Graph Theory
- Location: IBS, 2nd Floor of the Theory Building, Room B232 (Daejeon)
- Website: https://dimag.ibs.re.kr/event/2019-1-graph-theory/
- Organizer: Sang-il Oum, Younjin Kim