Seunghun Lee

activity

20172026

collaborators

8 papers

math.CO2026

Polytopes with large transversal ratio

Michael Gene Dobbins, Seunghun Lee

The transversal ratio of a polytope $P$ is the minimum proportion of vertices of $P$ required to intersect each facet of $P$ . The weak chromatic number of $P$ is the minimum number…

math.CO2023

On colorings of hypergraphs embeddable in $R^{d}$

Seunghun Lee, Eran Nevo

The (weak) chromatic number of a hypergraph $H$ , denoted by $χ (H)$ , is the smallest number of colors required to color the vertices of $H$ so that no hyperedge of $H$ is monochroma…

math.MG2022

Inscribable order types

Michael Gene Dobbins, Seunghun Lee

We call an order type inscribable if it is realized by a point configuration where the extreme points are all on a circle. In this paper, we investigate inscribability of order typ…

math.CO2021

Transversals and colorings of simplicial spheres

Joseph Briggs, Michael Gene Dobbins, Seunghun Lee

Motivated from the surrounding property of a point set in $R^{d}$ introduced by Holmsen, Pach and Tverberg, we consider the transversal number and chromatic number of a simp…

math.CO2020

Leray numbers of complexes of graphs with bounded matching number

Andreas F. Holmsen, Seunghun Lee

Given a graph $G$ on the vertex set $V$ , the non-matching complex of $G$ , $NM_{k} (G)$ , is the family of subgraphs $G^{'} \subset G$ whose matching number $ν (G^{'})$ is strictly le…

math.CO2019

The sandpile group of a trinity and a canonical definition for the planar Bernardi action

Tamás Kálmán, Seunghun Lee, Lilla Tóthmérész

Baker and Wang define the so-called Bernardi action of the sandpile group of a ribbon graph on the set of its spanning trees. This potentially depends on a fixed vertex of the grap…