Eun Jung Kim (김은정), Solving hard cut problems via flow-augmentation

Room B232 IBS (기초과학연구원)

We present a new technique for designing fixed-parameter algorithms for graph cut problems in undirected graphs, which we call flow augmentation. Our technique is applicable to problems that can be phrased as a search for an (edge) $(s, t)$-cut of cardinality at most $k$ in an undirected graph $G$ with designated terminals s and t.

Akanksha Agrawal, Polynomial Kernel for Interval Vertex Deletion

Zoom ID: 869 4632 6610 (ibsdimag)

Given a graph G and an integer k, the Interval Vertex Deletion (IVD) problem asks whether there exists a vertex subset S of size at most k, such that G-S is an interval graph. A polynomial kernel for a parameterized problem is a polynomial time preprocessing algorithm that outputs an equivalent instance of the problem whose size is bounded by

June Huh (허준이), Kazhdan-Lusztig polynomials of graphs and matroids

Room B232 IBS (기초과학연구원)

I will introduce Kazhdan-Lusztig polynomials of matroids and survey combinatorial and geometric theories built around them. The focus will be on the conjecture of Gedeon, Proudfoot, and Young that all zeros of the Kazhdan-Lusztig polynomial of a matroid lie on the negative real axis.

Robert Ganian, Solving Integer Linear Programs by Exploiting Variable-Constraint Interactions

Zoom ID: 869 4632 6610 (ibsdimag)

Integer Linear Programming (ILP) is among the most successful and general paradigms for solving computationally intractable optimization problems in computer science. ILP is NP-complete, and until recently we have lacked a systematic study of the complexity of ILP through the lens of variable-constraint interactions. This changed drastically in recent years thanks to a series of results that together lay out a

Postponed

Nonlinear Algebra in Daejeon (Postponed)

IBS Science Culture Center

Program Summer School @ KAIST (August 4-7, 2020) Discussion Weekend (August 8-9, 2020) Workshop @ IBS Science Culture Center (August 10-13, 2020) Website: https://dimag.ibs.re.kr/home/nonlinear/ Organizing Committee Insong Choe (Konkuk U.) Kangjin Han (DGIST) David Hyeon (SNU) Sijong Kwak (KAIST) Yongnam Lee (KAIST) Anton Leykin (Georgia Tech) Sang-il Oum (IBS & KAIST) Frank Sottile (TAMU)

Yunbum Kook (국윤범), Vertex Sparsification for Edge Connectivity

Room B232 IBS (기초과학연구원)

Graph compression or sparsification is a basic information-theoretic and computational question. A major open problem in this research area is whether $(1+\epsilon)$-approximate cut-preserving vertex sparsifiers with size close to the number of terminals exist. As a step towards this goal, we initiate the study of a thresholded version of the problem: for a given parameter $c$,

Tuan Tran, Anti-concentration phenomena

Room B232 IBS (기초과학연구원)

Let $X$ be a real random variable; a typical anti-concentration inequality asserts that (under certain assumptions) if an interval $I$ has small length, then $\mathbb{P}(X\in I)$ is small, regardless the location of $I$. Inequalities of this type have found powerful applications in many branches of mathematics. In this talk we will discuss several recent applications

Gwenaël Joret, Packing and covering balls in graphs excluding a minor

Zoom ID: 869 4632 6610 (ibsdimag)

In 2007, Chepoi, Estellon, and Vaxès conjectured that there exists a universal constant $c>0$ such that the following holds for every positive integers $r$ and $k$, and every planar graph $G$: Either $G$ contains $k$ vertex-disjoint balls of radius $r$, or there is a subset of vertices of size at most $c k$ meeting all

Livestream

2020 Combinatorics Workshop

Zoom ID: 869 4632 6610 (ibsdimag)

Combinatorics Workshop (조합론 학술대회) is the biggest annual conference in combinatorics in Korea. It was firstly held in 2004 by the Yonsei University BK21 Research Group. It has been advised by the committee of discrete mathematics of the Korean Mathematical Society since 2013. The aim of this workshop is to bring active researchers with different

Ben Lund, Point-plane incidence bounds

Room B232 IBS (기초과학연구원)

In the early 1980s, Beck proved that, if P is a set of n points in the real plane, and no more than g points of P lie on any single line, then there are $\Omega(n(n-g))$ lines that each contain at least 2 points of P. In 2016, I found a generalization of this theorem,

IBS 이산수학그룹 Discrete Mathematics Group
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