A Dominating Property of \(i\)-center in \(P_t\)-free Graphs

Jiping Liu1, Qinglin Yu2,3
1Department of Mathematics and Statistics Simon Fraser University Bumaby, B.C. Canada
2Department of Mathematics University College of The Cariboo and Department of Mathematics
3 Statistics Simon Fraser University Burnaby, B.C. Canada

Abstract

The \(i\)-center \(C_i(G)\) of a graph \(G\) is the set of vertices whose distances from any vertex of \(G\) are at most \(i\). A vertex set \(X\) \(k\)-dominates a vertex set \(Y\) if for every \(y \in Y\) there is a \(x \in X\) such that \(d(x,y) \leq k\). In this paper, we prove that if \(G\) is a \(P_t\)-free graph and \(i \geq \lfloor\frac{t}{2}\rfloor \), then \(C_i(G)\) \((q+1)\)-dominates \(C_{i+q}(G)\), as conjectured by Favaron and Fouquet [4].