Branches and Joints in the Study of Self Switching of Graphs

V. Vilfred1, J. Paulraj Joseph2, C. Jayasekaran3
1Department of Mathematics, St. Jude’s College, Thoothoor – 629 176, India.
2Department of Mathematics, Manonmanium Sundaranar University, Tirunelveli – 627 012, India.
3Department of Mathematics, Pioneer Kumaraswamy College, Nagercoil —- 629 003, India.

Abstract

A vertex \( v \in V(G) \) is said to be a self vertex switching of \( G \) if \( G \) is isomorphic to \( G^v \), where \( G^v \) is the graph obtained from \( G \) by deleting all edges of \( G \) incident to \( v \) and adding all edges incident to \( v \) which are not in \( G \). Two vertices \( u \) and \( v \) in \( G \) are said to be interchange similar if there exists an automorphism \( \alpha \) of \( G \) such that \( \alpha(u) = v \) and \( \alpha(v) = u \). In this paper, we give a characterization for a cut vertex in \( G \) to be a self vertex switching where \( G \) is a connected graph such that any two self vertex switchings, if they exist, are interchange similar.

Keywords: Switching, Self vertex switching, Interchange similar, Branches and Joints.