기초과학연구원 이산수학그룹
On October 21, 2025, William Cook from University of Waterloo gave a talk at the Discrete Math Seminar on using branch-decompositions for discrete optimization problems, including the traveling salesman problem. The title of his talk was “Optimization via Branch Decomposition“.
On October 14, 2025, Ilkyoo Choi (최일규) from Hankuk University of Foreign Studies and IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on the average degree of list-color-critical graphs and DP-color-critical graphs. The title of his talk was “An improved lower bound on the number of edges in list critical graphs via DP coloring“.
On September 30, 2025, Marcelo Sales from the University of California, Irvine, gave a talk at the Discrete Math Seminar about proving lower bounds on the Ramsey numbers of some hypergraphs. His talk was titled “On the Ramsey number of Daisies and other hypergraphs.”
On September 22, 2025, Rong Luo from West Virginia University gave a talk at the Discrete Math Seminar on nowhere-zero flows on signed graphs. His talk was titled “Modulo flows and Integer flows of signed graphs“.
On September 16, 2025, Mujin Choi (최무진) from KAIST and the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on unavoidable induced minors in graphs of large tree-independence number without a fixed induced star. The title of his talk was “Excluding ladder and wheel as induced minor in graphs without induced stars“.
On September 9, 2025, Katherine Perry from the Soka University of America gave a talk at the Discrete Math Seminar on the relationship between the distinguishing number and the fixing number of trees. The title of her talk was “Symmetry breaking in trees“.
On September 2, 2025, Zhifei Yan from the IBS Extremal Combinatorics and Probability Group gave a talk at the Discrete Math Seminar on covering the vertex set of a properly edge-colored graph with two vertex-disjoint rainbow cycles. The title of his talk was “A Rainbow version of Lehel’s conjecture“.
On August 29, 2025, Sang-il Oum (엄상일) from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on the Erdős-Pósa property for vertex-minors and perturbations of graphs. The title of his talk was “The Erdős-Pósa property for circle graphs as vertex-minors“.
The 2025 Korean Student Combinatorics Workshop (KSCW2025, 2025 조합론 학생 워크샵) was held in The-K Hotel Gyeongju from August 20 to August 24, 2025. Sponsored by the IBS Discrete Mathematics Group, this event aims to provide a platform for Korean graduate students working on combinatorics and related areas to establish a foundation for collaborative research. This is a continuation of the same workshop held last year.
This workshop was organized by the following four graduate students.
On August 12, 2025, Chien-Chung Huang from CNRS, DI ENS gave a talk at the Discrete Math Seminar on finding a small substructure in a matroid that allows a good approximation for the matroid intersection while having some robustness properties. His talk was titled “Robust Sparsification for Matroid Intersection with Applications.”