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List colorings of $k$-partite $k$-graphs

Combinatorics 2025-10-17 v4

Abstract

A kk-uniform hypergraph (or kk-graph) H=(V,E)H = (V, E) is kk-partite if VV can be partitioned into kk sets V1,,VkV_1, \ldots, V_k such that each edge in EE contains precisely one vertex from each ViV_i. In this note, we consider list colorings for such hypergraphs. We show that for any ε>0\varepsilon > 0 if each vertex vV(H)v \in V(H) is assigned a list of size L(v)((k1+ε)Δ/logΔ)1/(k1)|L(v)| \geq \left((k-1+\varepsilon)\Delta/\log \Delta\right)^{1/(k-1)}, then HH admits a proper LL-coloring, provided Δ\Delta is sufficiently large. Up to a constant factor, this matches the bound on the chromatic number of simple kk-graphs shown by Frieze and Mubayi, and that on the list chromatic number of triangle free kk-graphs shown by Li and Postle. Our results hold in the more general setting of ``color-degree'' as has been considered for graphs. Furthermore, we establish a number of asymmetric statements matching results of Alon, Cambie, and Kang for bipartite graphs.

Keywords

Cite

@article{arxiv.2311.03111,
  title  = {List colorings of $k$-partite $k$-graphs},
  author = {Abhishek Dhawan},
  journal= {arXiv preprint arXiv:2311.03111},
  year   = {2025}
}

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12 pages