기초과학연구원 이산수학그룹
On May 27, 2025, Meike Hatzel from the IBS Discrete Mathematics Group gave a talk at the Discrete Math Seminar on the existence of a graph of arbitrary large girth and chromatic number admitting a proper edge coloring without a color appearing alone in any cycle. The title of her talk was “Counterexample to Babai’s lonely colour conjecture“.
On May 13, 2025, Seokbeom Kim (김석범) from KAIST and the IBS Discrete Mathematics Group gave a talk on the structure of tournaments without a fixed 5-vertex tournament and its applications to the dichromatic number at the Discrete Math Seminar. The title of his talk was “The structure of △(1, 2, 2)-free tournaments“.
On April 29, 2025, Eunjin Oh (오은진) from POSTECH gave a talk at the Discrete Math Seminar on an almost linear-time approximation algorithm for the minimum-weight b-edge cover on geometric complete bipartite graphs. The title of her talk was “Approximation Algorithms for the Geometric Multimatching Problem“.
On April 28, 2025, Pascal Schweitzer from the Technical University of Darmstadt gave a talk on finding symmetries and deciding isomorphic graphs at the Discrete Math Seminar. The title of his talk was “Recent insights surrounding combinatorial approaches to isomorphism and symmetry problems“.
On April 22, 2025, Marcin Briański from Jagiellonian University in Krakóv, Poland gave a talk on the existence of large Burling graphs or large complete graphs on string graphs of very large chromatic number at the Discrete Math Seminar. The title of his talk was “Burling Graphs as (almost) universal obstacles to 𝜒-boundedness“.
On April 15, 2025, Nicola Lorenz from the University of Hamburg gave a talk on the existence of a normal tree spanning a given set of vertices in an infinite graph in terms of the coloring number of rooted minors at the Discrete Math Seminar. The title of her talk was “A Minor Characterisation of Normally Spanned Sets of Vertices“.
On April 14, 2025, Daniel McGinnis from Princeton University gave a talk on determining the existence of a k-dimensional affine subspace intersecting every member of a given finite family of convex sets in the d-dimensional real space at the Discrete Math Seminar. The title of his talk was “A necessary and sufficient condition for k-transversals“.
On April 8, 2025, Marcelo Garlet Milani from NII, Japan gave a talk at the Discrete Math Seminar on an alternative proof of the directed grid theorem. The title of his talk was “Cycles of Well-Linked Sets and an Elementary Bound for the Directed Grid Theorem“.
On April 1, 2025, Hyunwoo Lee (이현우) from KAIST and IBS Extremal Combinatorics and Probability Group gave a talk at the Discrete Math Seminar on the problem of determinining the matching polynomial of k-uniform hypergraphs from the list of all induced subhypergraphs of fixed size. The title of his talk was “Reconstructing hypergraph matching polynomials“.
On March 18, 2025, Michał T. Seweryn from Charles University gave a talk at the Discrete Math Seminar showing that every poset of very large dimension with a planar cover graph has Kelly’s poset of large dimension. The title of his talk was “Dimension and standard examples in planar posets“.