Completely Strong Path-Connectivity of Local Tournaments

Bu Yue Hua1, Zhang Ke Min2
1Department of Mathematics Zhejiang Normal University Jinhua 321004 China
2Department of Mathematics Nanjing University Nanjing 210008 China

Abstract

Let \(T = (V,A)\) be an oriented graph with \(n\) vertices. \(T\) is completely strong path-connected if for each arc \((a,b) \in A\) and \(k\) (\(k = 2, \ldots, n-1\)), there is a path from \(b\) to \(a\) of length \(k\) (denoted by \(P_k(a,b)\)) and a path from \(a\) to \(b\) of length \(k\) (denoted by \(P’_k(a,b)\)) in \(T\). In this paper, we prove that a connected local tournament \(T\) is completely strong path-connected if and only if for each arc \((a,b) \in A\), there exist \(P_2(a,b)\) and \(P’ _2(a,b)\) in \(T\), and \(T\) is not of \(T_1 \ncong T_0\)-\(D’_8\)-type digraph and \(D_8\).