Ringi Kim

activity

20142020

k

-chromatic digraphs

4 citations · 5 across the 5 of their papers we have counts for

collaborators

5 papers

math.CO2020★ 1 cited

Generalized list colouring of graphs

Eun-Kyung Cho, Ilkyoo Choi, Yiting Jiang +4

This paper disproves a conjecture of Wang, Wu, Yan and Xie, and answers in negative a question in Dvorak, Pekarek and Sereni. In return, we pose five open problems.

math.CO2019

Largest 2-regular subgraphs in 3-regular graphs

Ilkyoo Choi, Ringi Kim, Alexandr Kostochka +2

For a graph $G$ , let $f_{2} (G)$ denote the largest number of vertices in a $2$ -regular subgraph of $G$ . We determine the minimum of $f_{2} (G)$ over $3$ -regular $n$ -vertex simple graphs…

math.CO2019

Maximum $k$ -sum $n$ -free sets of the 2-dimensional integer lattice

Ilkyoo Choi, Ringi Kim, Boram Park

For a positive integer $n$ , let $[n]$ denote ${1, \dots, n}$ . For a 2-dimensional integer lattice point $b$ and positive integers $k \geq 2$ and $n$ , a \textit{ $k$ -sum $…

math.CO2016★ 4 cited

Cycles with two blocks in $k$ -chromatic digraphs

Ringi Kim, Seog-Jin Kim, Jie Ma +1

Let $k$ and $ℓ$ be positive integers. A cycle with two blocks $c (k, ℓ)$ is an oriented cycle which consists of two internally (vertex) disjoint directed paths of lengths at le…

math.CO2014

Disjoint dijoins

Maria Chudnovsky, Katherine Edwards, Ringi Kim +2

A dijoin in a digraph is a set of edges meeting every directed cut. D. R. Woodall conjectured in 1976 that if G is a digraph, and every directed cut of G has at least k edges, then…