On the Choosability of Bipartite Graphs

Abstract

Let \(u\) be an odd vertex of a bipartite graph \(B\) and suppose that \(f : V(B) \to \mathbb{N}\) is a function such that \(f(u) = \left\lceil d_B(u)/2 \right\rceil\) and \(f(v) = \left\lceil d_B(v)/2 \right\rceil + 1\) for \(v \in V(B) \setminus u\), where \(d_B(v)\) is the degree of \(v\) in \(B\). In this paper, we prove that \(B\) is \(f\)-choosable.