기초과학연구원 이산수학그룹
On March 28, 2023, Tianchi Yang from the National University of Singapore gave a talk at the Discrete Math Seminar about the maximum number of edges in an n-vertex k-critical graph. The title of his talk was “On the maximum number of edges in k-critical graphs.”
On March 21, 2023, Younjin Kim (김연진) from the IBS Extremal Combinatorics and Probability Group gave a talk at the Discrete Math Seminar on the overview of her results in extremal combinatorics. The title of her talk was “Problems on Extremal Combinatorics.”
On March 16, 2023, Paul Seymour from Princeton University gave an online talk at the Virtual Discrete Math Colloquium on the existence of a clique or an independent set of size at least $2^{c\sqrt{\log n \log \log n}}$ in an $H$-free graph. The title of his talk was “A loglog step towards the Erdős-Hajnal conjecture.”
On March 14, 2023, Stijn Cambie from the IBS Extremal Probability and Combinatorics Group gave a talk at the Discrete Math Seminar on recent developments regarding the union-closed sets conjecture initiated by Justin Gilmer. The title of his talk was “Recent progress on the Union-closed conjecture and related“.
On March 7, 2023, Eunjin Oh (오은진) from POSTECH gave a talk at the Discrete Math Seminar on a new faster algorithm for solving the disjoint paths problem on planar graphs. The title of her talk was “Parameterized algorithms for the planar disjoint paths problem“.
On February 28, 2023, Maya Sankar from Stanford University gave a talk at the Discrete Math Seminar about an extremal problem on 2-dimensional simplicial complexes analogous to Mader’s theorem on the number of edges in a graph without a subdivision of a fixed complete graph. The title of her talk was “The Turán Numbers of Homeomorphs“.
On February 21, 2023, Meike Hatzel from the National Institute of Informatics in Tokyo gave a talk at the Discrete Math Seminar on the parameterized complexity of the Directed Multicut problem with three pairs of terminals, which is to find a vertex cut of size at most k separating three pairs of terminals. The title of her talk was “Fixed-Parameter Tractability of Directed Multicut with Three Terminal Pairs Parametrised by the Size of the Cutset: Twin-Width Meets Flow-Augmentation“.
On February 15, 2023, Robert Hickingbotham from Monash University gave an online talk at the Virtual Discrete Math Colloquium on the relation between the tree-width and the Hadwiger number of circle graphs. The title of his talk was “Treewidth, Circle Graphs and Circular Drawings“.
On February 14, 2023, Raphael Steiner from ETH Zürich gave a talk at the Discrete Math Seminar on a stronger version of Hadwiger’s conjecture, which finds a clique minor in which one of its branch set is a singleton. The title of his talk was “Strengthening Hadwiger’s conjecture for 4- and 5-chromatic graphs“. He is currently visiting the IBS discrete mathematics group for 2 weeks.
On February 6-10, 2023, Will Perkins from Georgia Institute of Technology visited the IBS and gave a lecture for 5 days at the winter school “Statistical Physics and Combinatorics.” This winter school was organized by the IBS Extremal Combinatorics and Probability Group and Shandong University.