Enumeration of spanning trees of middle graphs

Autor: Weigen Yan
Rok vydání: 2017
Předmět:
Zdroj: Applied Mathematics and Computation. 307:239-243
ISSN: 0096-3003
Popis: Let G be a simple graph with n vertices and m edges, and and the maximum degree and minimum degree of G. Suppose G is the graph obtained from G by attaching dG(v) pendent edges to each vertex v of G. Huang and Li (Bull. Aust. Math. Soc. 91(2015), 353367) proved that if G is regular (i.e., =,G=G), then the middle graph of G, denoted by M(G), has 2mn+1m1t(G) spanning trees, where t(G) is the number of spanning trees of G. In this paper, we prove that t(M(G)) can be expressed in terms of the summation of weights of spanning trees of G with some weights on its edges. Particularly, we prove that if G is irregular (i.e., ), then t(M(G))=2mn+1m+k1t(G), where k is the number of vertices of degree one in G.
Databáze: OpenAIRE