English

List-avoiding orientations

Combinatorics 2024-06-21 v2

Abstract

Given a graph GG with a set F(v)F(v) of forbidden values at each vV(G)v \in V(G), an FF-avoiding orientation of GG is an orientation in which deg+(v)∉F(v)deg^+(v) \not \in F(v) for each vertex vv. Akbari, Dalirrooyfard, Ehsani, Ozeki, and Sherkati conjectured that if F(v)<12deg(v)|F(v)| < \frac{1}{2} deg(v) for each vV(G)v \in V(G), then GG has an FF-avoiding orientation, and they showed that this statement is true when 12\frac{1}{2} is replaced by 14\frac{1}{4}. In this paper, we take a step toward this conjecture by proving that if F(v)<13deg(v)|F(v)| < \lfloor \frac{1}{3} deg(v) \rfloor for each vertex vv, then GG has an FF-avoiding orientation. Furthermore, we show that if the maximum degree of GG is subexponential in terms of the minimum degree, then this coefficient of 13\frac{1}{3} can be increased to 21o(1)0.414\sqrt{2} - 1 - o(1) \approx 0.414. Our main tool is a new sufficient condition for the existence of an FF-avoiding orientation based on the Combinatorial Nullstellensatz of Alon and Tarsi.

Cite

@article{arxiv.2209.09107,
  title  = {List-avoiding orientations},
  author = {Peter Bradshaw and Yaobin Chen and Hao Ma and Bojan Mohar and Hehui Wu},
  journal= {arXiv preprint arXiv:2209.09107},
  year   = {2024}
}
R2 v1 2026-06-28T01:39:58.062Z