Equivalence between Extendibility and Factor-Criticality

Zan-Bo Zhang1,2, Tao Wang3, Dingjun Lou1
1Department of Computer Science, Sun Yat-sen University, Guangzhou 510275, China
2Department of Computer Engineering, Guangdong Industry Technical College, Guangzhou 510300, China
3Center for Combinatorics, LPMC, Nankai University, Tianjin 300071, China

Abstract

In this paper, we show that if \(k \geq \frac{v+2}{4}\), where \(v\) denotes the order of a graph, a non-bipartite graph \(G\) is \(k\)-extendable if and only if it is \(2k\)-factor-critical. If \(k \geq \frac{v-3}{4}\), a graph \(G\) is \(k\)-extendable if and only if it is \((2k+1)\)-factor-critical. We also give examples to show that the two bounds are best possible. Our results are answers to a problem posted by Favaron \([3]\) and Yu \([11]\).