On line graphs with maximum energy

Autor: María Robbiano, Eber Lenes, Exequiel Mallea-Zepeda, Z Jonnathan Rodríguez
Rok vydání: 2018
Předmět:
Zdroj: Linear Algebra and its Applications. 545:15-31
ISSN: 0024-3795
Popis: For an undirected simple graph G, the line graph L ( G ) is the graph whose vertex set is in one-to-one correspondence with the edge set of G where two vertices are adjacent if their corresponding edges in G have a common vertex. The energy E ( G ) is the sum of the absolute values of the eigenvalues of G. The vertex connectivity κ ( G ) is referred as the minimum number of vertices whose deletion disconnects G. The positive inertia ν + ( G ) corresponds to the number of positive eigenvalues of G. Finally, the matching number β ( G ) is the maximum number of independent edges of G. In this paper, we derive a sharp upper bound for the energy of the line graph of a graph G on n vertices having a vertex connectivity less than or equal to k. In addition, we obtain upper bounds on E ( G ) in terms of the edge connectivity, the inertia and the matching number of G. Moreover, a new family of hyperenergetic graphs is obtained.
Databáze: OpenAIRE