Myungho Choi

activity

20242026

collaborators

6 papers

math.CO2026

$2$ -limited broadcast domination in cubic graphs

Myungho Choi, Boram Park

For a graph $G$ , a function $f : V (G) \to {0, 1, 2}$ is called a $2$ -limited dominating broadcast on $G$ if for every vertex $u$ , there exists a vertex $v$ such that $f (v) > 0$ and the…

math.CO2025

Digraphs in which every $t$ vertices have exactly $I^»$ common out-neighbors

Myungho Choi, Hojin Chu, Suh-Ryung Kim

We say that a digraph is a $(t, I^»)$ -liking digraph if every $t$ vertices have exactly $I^»$ common out-neighbors. In 1975, PlesnÃk [Graphs with a homogeneity, 1975. {\it Glasnik Ma…

math.CO2025

A digraph version of the Friendship Theorem

Myungho Choi, Hojin Chu, Suh-Ryung Kim

The Friendship Theorem states that if in a party any pair of persons has precisely one common friend, then there is always a person who is everybody's friend and the theorem has be…

math.CO2024

Multipartite tournaments in which any two vertices have an $(i, j)$ -step common out-neighbor

Myungho Choi, Suh-Ryung Kim

We say that a digraph $D$ is $(i, j)$ -step competitive if any two vertices have an $(i, j)$ -step common out-neighbor in $D$ and that a graph $G$ is $(i, j)$ -step competitively orienta…

math.CO2024

Extensions of results on phylogeny graphs of degree bounded digraphs

Myungho Choi, Suh-Ryung Kim

An acyclic digraph in which every vertex has indegree at most $i$ and outdegree at most $j$ is called an $(i, j)$ digraph for some positive integers $i$ and $j$ . The phylogeny graph…

math.CO2024

Competition-common enemy graphs of degree-bounded digraphs

Myungho Choi, Hojin Chu, Suh-Ryung Kim

The competition-common enemy graph (CCE graph) of a digraph $D$ is the graph with the vertex set $V (D)$ and an edge $uv$ if and only if $u$ and $v$ have a common predator and a com…

2-limited broadcast domination in cubic graphs

Digraphs in which every t vertices have exactly I^» common out-neighbors

A digraph version of the Friendship Theorem

Multipartite tournaments in which any two vertices have an (i,j)-step common out-neighbor

Extensions of results on phylogeny graphs of degree bounded digraphs

Competition-common enemy graphs of degree-bounded digraphs

$2$ -limited broadcast domination in cubic graphs

Digraphs in which every $t$ vertices have exactly $I^»$ common out-neighbors

Multipartite tournaments in which any two vertices have an $(i, j)$ -step common out-neighbor