English

Vertex weighted Laplacian graph energy and other topological indices

Combinatorics 2016-09-14 v1

Abstract

Let GG be a graph with a vertex weight ω\omega and the vertices v1,,vnv_1,\ldots,v_n. The Laplacian matrix of GG with respect to ω\omega is defined as Lω(G)=diag(ω(v1),,ω(vn))A(G)L_\omega(G)=\mathrm{diag}(\omega(v_1),\cdots,\omega(v_n))-A(G), where A(G)A(G) is the adjacency matrix of GG. Let μ1,,μn\mu_1,\cdots,\mu_n be eigenvalues of Lω(G)L_\omega(G). Then the Laplacian energy of GG with respect to ω\omega defined as LEω(G)=i=1nμiωˉLE_\omega (G)=\sum_{i=1}^n\big|\mu_i - \bar{\omega}\big|, where ωˉ\bar{\omega} is the average of ω\omega, i.e., ωˉ=i=1nω(vi)n\bar{\omega}=\dfrac{\sum_{i=1}^{n}\omega(v_i)}{n}. In this paper we consider several natural vertex weights of GG and obtain some inequalities between the ordinary and Laplacian energies of GG with corresponding vertex weights. Finally, we apply our results to the molecular graph of toroidal fullerenes (or achiral polyhex nanotorus).

Keywords

Cite

@article{arxiv.1609.01425,
  title  = {Vertex weighted Laplacian graph energy and other topological indices},
  author = {Reza Sharafdini and H. Panahbar},
  journal= {arXiv preprint arXiv:1609.01425},
  year   = {2016}
}