Szeged Index of a Zig-zag Polyhex Nanotube

B. Manoochehrian1, H. Yousefi-Azari2, A. R. Ashrafi3
1Academic Center for Education, Culture and Research, Tehran Branch, Tehran, 1. R. Iran
2Center of Excellence in Biomathematics, School of Mathematics, Statistics and Computer Science, University of Tehran, Tehran, I. R. Iran
3Department of Mathematics, Faculty of Science, University of Kashan, Kashan 87317-51167, 1. R. Iran

Abstract

The Szeged index extends the Wiener index for cyclic graphs by counting the number of atoms on both sides of each bond and summing these counts. This index was introduced by Ivan Gutman at the Attila Jozsef University in Szeged in \(1994\), and is thus called the Szeged index. In this paper, we introduce a novel method for enumerating by cuts. Using this method, an exact formula for the Szeged index of a zig-zag polyhex nanotube \(T = TUHC_6{[p,q]}\) is computed for the first time.