2025 Korean Student Combinatorics Workshop (KSCW2025: 2025 조합론 학생 워크샵)

Contribution List

3. Oriented Matroids: Scope & Perspectives

Seunghun Lee (IBS DIMAG)

21/08/2025, 11:00

Invited talks

This is a very brief introduction to oriented matroids based on personal recollection, with hope that the theory gets wider attention from younger generation of mathematics in Korea.

5. Unifying Islands of Tractability for Maximum Independent Set

Gunwoo Kim (KAIST & IBS DIMAG)

22/08/2025, 09:30

Contributed talks

The Maximum Independent Set (MIS) problem is NP-complete and remains so for every minor-closed graph class that includes all planar graphs (Garey and Johnson [SIAM J. Appl. Math.'77]). On the other hand, due to the Grid Theorem of Robertson and Seymour [JCTB'95], every minor-closed graph class that excludes a planar graph has bounded treewidth, and MIS can be solved in polynomial time on such...

4. Things I worry about as a Postdoc

Hojin Chu (KIAS)

22/08/2025, 13:30

Invited talks

In this talk, I’ll share a few of these thoughts, from research focus to future planning, in the hope that they resonate with others in similar stages. There won’t be any magic answers, but maybe a few ideas that help make the uncertainty a bit more manageable.

8. Approximation Algorithm for the Geometric Multimatching Problem

Shinwoo An (POSTECH)

23/08/2025, 09:30

Contributed talks

Matching is one of the most fundamental combinatorial objects in both graph theory and combinatorial optimization. Moreover, a lot of variants of have been studied in both exact and approximation settings. In the first part of my talk, I will present several classical graph matching algorithms and illustrate some intuitions and techniques behind them.

Then I will focus on the geometric...

9. Linear-Time Computation of the Frobenius Normal Form for Symmetric Toeplitz Matrices via Graph-Theoretic Decomposition

Homoon Ryu (Ajou University)

23/08/2025, 13:30

Contributed talks

We introduce a linear-time algorithm for computing the Frobenius normal form (FNF) of symmetric Toeplitz matrices by utilizing their inherent structural properties through a graph-theoretic approach. Previous results of the authors established that the FNF of a symmetric Toeplitz matrix is explicitly represented as a direct sum of symmetric irreducible Toeplitz matrices, each corresponding to...

7. Progress on Covering a Hexagon with Seven Unit Triangles

Jeewon Kim (KAIST)

24/08/2025, 09:30

Contributed talks

John Conway and Alexander Soifer showed that an equilateral triangle T with side length n+ε can be covered using n²+2 unit equilateral triangles. They also conjectured that using n²+1 triangles is not enough.

As a more approachable version of this problem, we ask: Can a regular hexagon with side length 1+ε be covered by just 7 unit equilateral triangles? This simplified question reflects...

6. Capturing Additive Structures via Gowers Norms: From Arithmetic Progression Counts to Inverse Theorems

Jihyo Chae (Yonsei University)

24/08/2025, 10:10

Contributed talks

The Gowers uniformity norm has played a significant role in additive combinatorics as a measure of randomness associated with solution sets of certain linear configurations. In this talk, I introduce the notion of Gowers uniformity norms and demonstrate how they capture additive structures in a given set of integers. Gowers norms capture additive structures both through k-term arithmetic...