English

On triangle-free list assignments

Combinatorics 2022-03-08 v1

Abstract

We show that Bernshteyn's proof of the breakthrough result of Molloy that triangle-free graphs are choosable from lists of size (1+o(1))Δ/logΔ(1+o(1))\Delta/\log\Delta can be adapted to yield a stronger result. In particular one may prove that such list sizes are sufficient to colour any graph of maximum degree Δ\Delta provided that vertices sharing a common colour in their lists do not induce a triangle in GG, which encompasses all cases covered by Molloy's theorem. This was thus far known to be true for lists of size (1000+o(1))Δ/logΔ(1000+o(1))\Delta/\log\Delta, as implies a more general result due to Amini and Reed. We also prove that lists of length 2(r2)Δlog2log2Δ/log2Δ2(r-2)\Delta \log_2\log_2\Delta/\log_2\Delta are sufficient if one replaces the triangle by any KrK_r with r4r\geq 4, pushing also slightly the multiplicative factor of 200r200r from Bernshteyn's result down to 2(r2)2(r-2). All bounds presented are also valid within the more general setting of correspondence colourings.

Keywords

Cite

@article{arxiv.2203.02980,
  title  = {On triangle-free list assignments},
  author = {Jakub Przybyło},
  journal= {arXiv preprint arXiv:2203.02980},
  year   = {2022}
}

Comments

16 pages

R2 v1 2026-06-24T10:03:41.209Z