Some Analytical Properties of the Permanental Polynomial of a Graph

Tingzeng Wu1,2, Heping Zhang2
1School of Mathematics and Statistics, Qinghai Nationalities University, Xining, Qinghai 810007, P. R. China
2School of Mathematics and Statistics, Lanzhou University, Lanzhou, Gansu 730000, P. R. China

Abstract

Let \(G\) be a graph and \(\pi(G, x)\) its permanental polynomial. A vertex-deleted subgraph of \(G\) is a subgraph \(G – v\) obtained by deleting from \(G\) vertex \(v\) and all edges incident to it. In this paper, we show that the derivative of the permanental polynomial of \(G\) equals the sum of permanental polynomials of all vertex-deleted subgraphs of \(G\). Furthermore, we discuss the permanental polynomial version of Gutman’s problem [Research problem \(134\), Discrete Math. \(88 (1991) 105–106\)], and give a solution.