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math.CO2019

The niche graphs of multipartite tournaments

Soogang Eoh, Myungho Choi, Suh-Ryung Kim

The niche graph of a digraph has as the vertex set and an edge if and only if and , or and for so…

math.CO2019

Using -row graphs to study -competition graphs

Soogang Eoh, Taehee Hong, Suh-Ryung Kim +1

For a positive integer , the -competition graph of a digraph is a graph which has the same vertex set as and an edge between distinct vertices and if and only…

math.CO2019

The phylogeny number in the aspect of triangles and diamonds of a graph

Soogang Eoh, Suh-Ryung Kim, Hojun Lee

Given an acyclic digraph , the competition graph of , denoted by , is the simple graph having vertex set and edge set $\{uv \mid (u, w), (v, w) \in A(D) \text{ f…

math.CO2019

On weak majority dimensions of digraphs

Soogang Eoh, Suh-Ryung Kim

In this paper, we introduce the notion of the weak majority dimension of a digraph which is well-defined for any digraph. We first study properties shared by the weak dimension of…

math.CO2019

On -step competition graphs of bipartite tournaments

Soogang Eoh, Suh-Ryung Kim, Hyesun Yoon

In this paper, we completely characterize the -step competition graph of a bipartite tournament for any integer . In addition, we compute the competition index and the…

math.CO2018

On chordal phylogeny graphs

Soogang Eoh, Suh-Ryung Kim

An acyclic digraph each vertex of which has indegree at most and outdegree at most is called an digraph for some positive integers and . Lee {\it et al.} (2…