기초과학연구원 이산수학그룹
On June 16, 2020, Andreas Holmsen from KAIST presented his recent work with Xavier Goaoc and Zuzana Patáková on generalizing the fractional Halley theorem under very weak topological assumptions. The title of his talk was “Fractional Helly and topological complexity“.
On June 9, 2020, Jiseung Kim (김지승) from KIAS presented a talk on some aspects of cryptography, including his recent work “Adventures in Crypto Dark Matter: Attacks, Fixes, and Analysis of weak PRF” jointly with Jung Hee Cheon, Wonhee Cho, and Jeong Han Kim. The title of his talk was “Hardness and concrete security in cryptography“.
On June 2, 2020, Huy-Tung Nguyen from KAIST gave a talk on the graph parameter called the average cut-rank of a graph. The title of his talk is “The average cut-rank of graphs“.
On May 26, 2020, Hong Liu from University of Warwick presented a talk on his recent work describing approximate structures of an n-vertex m-edge graph minimizing the number of cliques of size k. The title of his talk was “Asymptotic Structure for the Clique Density Theorem”.
On May 19, 2020, O-joung Kwon (권오정) from Incheon National University and IBS Discrete Mathematics Group presented a survey talk on the MIM-width of graphs. The title of his talk was “Mim-width: a width parameter beyond rank-width“.
Note added on June 2020
After I presented the talk, Benjamin Bergougnoux commented me that the claim of (Boyaci, Ekim, Shalom 17) at 1:02:40 was recently disproved by Kratochvíl, Masařík, and Novotná (https://arxiv.org/abs/2002.08311). I would like to thank Benjamin for the comment. Whether or not there is a polynomial-time algorithm for Max Cut on proper interval graphs is still open.
On May 12, 2020, Eun Jung Kim (김은정) from LAMSADE, CNRS presented a talk on her recent work on the twin-width. The title of her talk was “Twin-width: tractable FO model checking“. She is visiting the IBS discrete mathematics group from May 12 for about 4 months.
On April 28, 2020, Seunghun Lee (이승훈) from KAIST presented a talk on the topological property of the non-matching complex, that is a simplicial complex consisting of subgraphs on the same vertex set having no matching of size k and its application to the rainbow matching problem of graphs. The title of his talk is “Leray numbers of complexes of graphs with bounded matching number“.
On April 21, 2020, Sang-il Oum gave a survey talk on vertex-minors of graphs at the discrete math seminar. The title of his talk was “survey on vertex-minors“.
On April 14, 2020, Casey Tompkins from IBS discrete mathematics group gave a talk on the saturation version of the problems related to the Erdős-Szekeres theorem on convex k-gons, sequences, and posets. The title of his talk is “Saturation problems in the Ramsey theory of graphs, posets and point sets“.
On April 7, 2020, Pascal Gollin presented his work on the relation between the packing of edge sets intersecting all directed cuts in some class B and the maximum size of a minimal nonempty directed cut in B, motivated by Woodall’s conjecture. The title of his talk is “Disjoint dijoins for classes of dibonds in finite and infinite digraphs“.