#New_accepted_paper

Colorful fractional Helly theorem via weak saturation Two celebrated extensions of the classical Helly's theorem are the fractional Helly theorem and the colorful Helly theorem. Bulavka, Goodarzi, and Tancer recently established the optimal bound for the...

#New_accepted_paper
Debsoumya Chakraborti, Minho Cho, *Jinha Kim*, and Minki Kim,
Colorful fractional Helly theorem via weak saturation,
Electron. J. Combin., accepted, 2026.
arxiv.org/abs/2408.15093

$f$-Diophantine sets over finite fields via quasi-random hypergraphs from multivariate polynomials We investigate $f$-Diophantine sets over finite fields via new explicit constructions of families of quasi-random hypergraphs from multivariate polynomials. In particular, our construction not only of...

#New_accepted_paper
Seoyoung Kim, Chi Hoi Yip, and *Semin Yoo*,
f-Diophantine sets over finite fields via quasi-random hypergraphs from multivariate polynomials,
Mathematika, accepted, 2026.
arxiv.org/abs/2503.19603

A lower bound on the number of edges in DP-critical graphs A graph $G$ is $k$-critical (list $k$-critical, DP $k$-critical) if $χ(G)= k$ ($χ_\ell(G)= k$, $χ_\mathrm{DP}(G)= k$) and for every proper subgraph $G'$ of $G$, $χ(G')<k$ ($χ_\ell(G')< k$, $χ_\mathrm{...

#New_accepted_paper
Peter Bradshaw, *Ilkyoo Choi*, Alexandr Kostochka, and Jingwei Xu,
A lower bound on the number of edges in DP-critical graphs,
J. Combin. Theory Ser. B, accepted, 2026.
arxiv.org/abs/2409.00937

Triangulated spheres with holes in triangulated surfaces Let $\mathbb{S}_h$ denote a sphere with $h$ holes. Given a triangulation $G$ of a surface $\mathbb{M}$, we consider the question of when $G$ contains a spanning subgraph $H$ such that $H$ is a triangu...

#New_accepted_paper
Katie Clinch, Sean Dewar, Niloufar Fuladi, *Maximilian Gorsky*, *Tony Huynh*, Eleftherios Kastis, Atsuhiro Nakamoto, Anthony Nixon, and Brigitte Servatius,
Triangulated spheres with holes in triangulated surfaces,
Discrete Comput. Geom., accepted, 2026.
arxiv.org/abs/2410.04450

On a variant of dichromatic number for digraphs with prescribed sets of arcs In this paper, we consider a variant of dichromatic number on digraphs with prescribed sets of arcs. Let $D$ be a digraph and let $Z_1, Z_2$ be two sets of arcs in $D$. For a subdigraph $H$ of $D$, le...

#New_accepted_paper
*O-joung Kwon* and Xiaopan Lian,
On a variant of dichromatic number for digraphs with prescribed sets of arcs,
Graphs and Combinatorics, accepted, 2026.
arxiv.org/abs/2307.05897

Unified almost linear kernels for generalized covering and packing problems on nowhere dense classes Let $\mathcal{F}$ be a family of graphs, and let $p,r$ be nonnegative integers. The \textsc{$(p,r,\mathcal{F})$-Covering} problem asks whether for a graph $G$ and an integer $k$, there exists a set $D...

#New_accepted_paper
*Jungho Ahn*, *Jinha Kim*, and *O-joung Kwon*,
Unified almost linear kernels for generalized covering and packing problems on nowhere dense classes,
J. Comput. System Sci., accepted, 2026.
arxiv.org/abs/2207.06660

Erdős-Pósa property of $A$-paths in unoriented group-labelled graphs We characterize the obstructions to the Erdős-Pósa property of $A$-paths in unoriented group-labelled graphs. As a result, we prove that for every finite abelian group $Γ$ and for every subset $Λ$ of ...

#New_accepted_paper
*O-joung Kwon* and Youngho Yoo,
Erdős-Pósa property of A-paths in unoriented group-labelled graphs,
Combinatorica, accepted, 2026.
arxiv.org/abs/2411.05372

Redirecting

#New_accepted_paper
P. S. Ardra, R. Krithika, Saket Saurabh, and *Roohani Sharma*,
Balanced Substructures in Bicolored Graphs,
Theoret. Comput. Sci., accepted, 2026.
doi.org/10.1016/j.tc...

Sphere intersections and incidences over finite fields We bound the number of incidences between points and spheres in finite vector spaces by bounding the sum of the number of points in the pairwise intersections of the spheres. We obtain new incidence b...

#New_accepted_paper
Doowon Koh, Ben Lund, Chuandong Xu, and *Semin Yoo*,
Sphere intersections and incidences over finite fields,
Proc. Amer. Math. Soc., accepted, 2025.
arxiv.org/abs/2509.25997

Star clusters in independence complexes of hypergraphs We study the concept of star clusters in simplicial complexes, which was introduced by Barmak in 2013, by relating it with the structure of hypergraphs that correspond to the simplicial complexes. Thi...

#New_accepted_paper
*Jinha Kim*,
Star clusters in independence complexes of hypergraphs,
Combinatorica, accepted, 2025.
arxiv.org/abs/2408.14321

Reduced bandwidth: a qualitative strengthening of twin-width in minor-closed classes (and beyond) In a reduction sequence of a graph, vertices are successively identified until the graph has one vertex. At each step, when identifying $u$ and $v$, each edge incident to exactly one of $u$ and $v$ is...

#New_accepted_paper
Édouard Bonnet, *O-joung Kwon*, and David R. Wood,
Reduced bandwidth: a qualitative strengthening of twin-width in minor-closed classes (and beyond),
J. Combin. Theory Ser. B, accepted, 2025.
arxiv.org/abs/2202.11858

Fragile minor-monotone parameters under random edge perturbation We conduct a quantitative analysis of how many random edges need to be added to a base graph $H$ in order to significantly increase natural minor-monotone graph parameters of the resulting graph $R$. ...

#New_accepted_paper
Dong Yeap Kang, Mihyun Kang, Jaehoon Kim, and *Sang-il Oum*,
Fragile minor-monotone parameters under random edge perturbation,
European J. Combin., accepted, 2025.
arxiv.org/abs/2005.09897

A unified Erdős-Pósa theorem for cycles in graphs labelled by multiple abelian groups In 1965, Erdős and Pósa proved that there is an (approximate) duality between the maximum size of a packing of cycles and the minimum size of a vertex set hitting all cycles. Such a duality does not h...

#New_accepted_paper
*J. Pascal Gollin*, *Kevin Hendrey*, *O-joung Kwon*, *Sang-il Oum*, and Youngho Yoo,
A unified Erdős-Pósa theorem for cycles in graphs labelled by multiple abelian groups,
Math. Ann., accepted, 2025.
arxiv.org/abs/2209.09488