The Alon-Tarsi number of planar graphs -- a simple proof
Yangyan Gu, Xuding Zhu·2022-03-30·via math.CO updates on arXiv.org
This paper gives a simple proof of the result that every planar graph $G$ has Alon-Tarsi number at most 5, and has a matching $M$ such that $G-M$ has Alon-Tarsi number at most 4.