Casey Tompkins, Inverse Turán Problems

Room B232 IBS (기초과학연구원)

For given graphs $G$ and $F$, the Turán number $ex(G,F)$ is defined to be the maximum number of edges in an $F$-free subgraph of $G$. Briggs and Cox introduced a dual version of this problem wherein for a given number $k$, one maximizes the number of edges in a host graph $G$ for which $ex(G,H)

Ilkyoo Choi (최일규), Flexibility of Planar Graphs

Room B232 IBS (기초과학연구원)

Oftentimes in chromatic graph theory, precoloring techniques are utilized in order to obtain the desired coloring result. For example, Thomassen's proof for 5-choosability of planar graphs actually shows that two adjacent vertices on the same face can be precolored. In this vein, we investigate a precoloring extension problem formalized by Dvorak, Norin, and Postle named flexibility. Given a

Paloma T. Lima, Graph Square Roots of Small Distance from Degree One Graphs

Zoom ID: 869 4632 6610 (ibsdimag)

Given a graph class $\mathcal{H}$, the task of the $\mathcal{H}$-Square Root problem is to decide whether an input graph G has a square root H that belongs to $\mathcal{H}$. We are interested in the parameterized complexity of the problem for classes $\mathcal{H}$ that are composed by the graphs at vertex deletion distance at most $k$

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

IBS 이산수학그룹 Discrete Mathematics Group
기초과학연구원 수리및계산과학연구단 이산수학그룹
대전 유성구 엑스포로 55 (우) 34126
IBS Discrete Mathematics Group (DIMAG)
Institute for Basic Science (IBS)
55 Expo-ro Yuseong-gu Daejeon 34126 South Korea
E-mail: dimag@ibs.re.kr, Fax: +82-42-878-9209
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