Abstract-Graph polynomials are important objects of research in graph theory. Particularly, the permanental polynomials are widely used in Physics and Chemistry. As the difficulty to evaluate the permanental polynomials, this paper deals with the computation of the permanental polynomials of graphs under various operations. Firstly, we give explicit expressions for the permanental polynomials of single subdivision graphs and bisubdivision graphs in recursive ways, respectively. Then we deduce the permanental polynomials of degree subdivision graphs by the product of matrices. Based on these, the permanental polynomials of those physical graphs and chemical graphs which can be generated by subdivision operations can be derived.Index Terms-Permanent, permanental polynomial, subdivision graph.
I. INTRODUCTIONThe permanental polynomials of graphs originate from Mathematics. Recently, they have attracted some interest in Chemistry, Physics and graph theory. For example, the Jones polynomial, which has deep connections with statistical mechanics, can be expressed as the permanent of a matrix [1]. Moreover, the computation of the transition amplitude of a quantum circuit can also be encoded as computing the permanent of a matrix [2]. In addition, the constant term of the permanental polynomial of a chemical graph enumerates the close-packed dimers (which is termed as perfect matchings in Mathematics) of a graph, and the coefficients and zeros of permanental polynomials are related to the stability and structure information of chemical graphs [3], [4]. Therefore, it is interesting and exciting to evaluate the permanental polynomials of graphs.As is well known, computing the permanent of a matrix is a #P-complete problem [5]. So it is very hard to compute the permanents and the permanental polynomials directly. Is there an efficient method to deal with the permanental polynomials of some interesting and special graphs? Many graphs widely used in Chemistry and Physics could be generated by a series of subdivision operations. Motivated by this, in this paper we provide ways to compute the permanental polynomials of subdivision graphs. We introduce some definitions and notations. u and v is denoted by e = (u, v). A cycle is a graph with an equal number of vertices and edges whose vertices can be placed around a circle so that two vertices are joined by an edge if and only if they appear consecutively along the circle.Let G be a finite and simple graph on n vertices. The permanental polynomial of G is defined as
The Permanental Polynomials of Subdivision Graphs Wei LiInternational Journal of Applied Physics and Mathematics, Vol. 4,No. 4 A graph G is a triple consisting of a vertex set V , an edge set E , and a relation that associates with each edge two vertices called the end-vertices. An edge e with end-vertices