Duksang Lee (이덕상), Intertwining connectivities for vertex-minors and pivot-minors

Room B232 IBS (기초과학연구원)

We show that for pairs (Q,R) and (S,T) of disjoint subsets of vertices of a graph G, if G is sufficiently large, then there exists a vertex v in V(G)−(Q∪R∪S∪T) such that there are two ways to reduce G by a vertex-minor operation while preserving the connectivity between Q and R and the connectivity between S

Linda Cook, Two results on graphs with holes of restricted lengths

Room B232 IBS (기초과학연구원)

We call an induced cycle of length at least four a hole. The parity of a hole is the parity of its length. Forbidding holes of certain types in a graph has deep structural implications. In 2006, Chudnovksy, Seymour, Robertson, and Thomas famously proved that a graph is perfect if and only if it does not contain

Eun Jung Kim (김은정), A Constant-factor Approximation for Weighted Bond Cover

Room B232 IBS (기초과학연구원)

The Weighted $\mathcal F$-Vertex Deletion for a class $\mathcal F$ of graphs asks, given a weighted graph $G$, for a minimum weight vertex set $S$ such that $G-S\in\mathcal F$. The case when $\mathcal F$ is minor-closed and excludes some graph as a minor has received particular attention but a constant-factor approximation remained elusive for Weighted $\mathcal

Ilkyoo Choi (최일규), On independent domination of regular graphs

Room B232 IBS (기초과학연구원)

Given a graph $G$, a dominating set of $G$ is a set $S$ of vertices such that each vertex not in $S$ has a neighbor in $S$. The domination number of $G$, denoted $\gamma(G)$, is the minimum size of a dominating set of $G$. The independent domination number of $G$, denoted $i(G)$, is the minimum size of a dominating

Sang-hyun Kim (김상현), On rational 2×2 matrices without relations

Room B232 IBS (기초과학연구원)

For a rational number $q= s/r$, we consider the two 2x2 matrices $A=\begin{pmatrix}1&0\\1&1\end{pmatrix}$ and  $B_q=\begin{pmatrix}1&q\\0&1\end{pmatrix}$. It is a long-standing conjecture (traced at least back to Rimhak Ree) that A and B(q) admit a nontrivial group relation if $|q|<4$; the converse is classical. For the special case $s≤27$ and $s\neq 24$, we prove this conjecture. We

2021 Combinatorics Workshop (2021 조합론 학술대회)

The Bloomvista

The annual conference on Combinatorics Workshop (조합론 학술대회) was begun in 2004 by the Yonsei University BK21 Research Group. Since 2013, this workshop has been advised by the committee of discrete mathematics of the Korean Mathematical Society. This year it will be held on November 4-6, 2021. The aim of this workshop is to bring

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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