Joonkyung Lee (이준경), On common graphs
Zoom ID:8628398170 (123450)A graph $H$ is common if the number of monochromatic copies of $H$ in a 2-edge-colouring of the complete graph $K_n$ is minimised by the random colouring. Burr and Rosta, extending …
Loading view.
Discrete Math Seminar
Hong Liu (刘鸿), A solution to Erdős and Hajnal’s odd cycle problem
Room B232 IBS (기초과학연구원)I will go over the history on the study of the set of cycle lengths of graphs with large average degree or chromatic number, and discuss recent work with Richard …
Jinha Kim (김진하), On a conjecture by Kalai and Meshulam – the Betti number of the independence complex of ternary graphs
Room B232 IBS (기초과학연구원)Given a graph G=(V,E), the independence complex of G is the abstract simplicial complex I(G) on V whose faces are the independent sets of G. A graph is ternary if it does …
O-joung Kwon (권오정), Directed tangles and applications
Room B232 IBS (기초과학연구원)The canonical tree-decomposition theorem, proved by Robertson and Seymour in their seminal graph minors series, turns out to be an extremely valuable tool in structural and algorithmic graph theory. In …
Andreas Holmsen, Discrete geometry in convexity spaces
Room B232 IBS (기초과학연구원)The notion of convexity spaces provides a purely combinatorial framework for certain problems in discrete geometry. In the last ten years, we have seen some progress on several open problems …
Ben Lund, Perfect matchings and derangements on graphs
Room B232 IBS (기초과학연구원)We show that each perfect matching in a bipartite graph G intersects at least half of the perfect matchings in G. This result has equivalent formulations in terms of the permanent …
Tuan Tran, Minimum saturated families of sets
Room B232 IBS (기초과학연구원)A family $\mathcal F$ of subsets of is called s-saturated if it contains no s pairwise disjoint sets, and moreover, no set can be added to $\mathcal F$ while preserving …
Doowon Koh (고두원), On the cone restriction conjecture in four dimensions and applications in incidence geometry
Room B232 IBS (기초과학연구원)Main purpose of this talk is to introduce a connection between restriction estimates for cones and point-sphere incidence theorems in the finite field setting. First, we review the finite field …
Martin Ziegler, Quantitative Coding and Complexity Theory of Continuous Data
Room B232 IBS (기초과학연구원)Specifying a computational problem requires fixing encodings for input and output: encoding graphs as adjacency matrices, characters as integers, integers as bit strings, and vice versa. For such discrete data, the actual encoding …
Minki Kim (김민기), Rainbow paths and rainbow matchings
Room B232 IBS (기초과학연구원)We prove that if $n \geq 3$, then any family of $3n-3$ sets of matchings of size $n$ in any graph has a rainbow matching of size $n$. This improves …