An increasing sequence of lower bounds for the Estrada index of graphs and matrices

Some Lower Bounds for Estrada Index

Ela Lower Bounds for the Estrada Index of Graphs

The Estrada index was used to study the folding degree of proteins and other long-chain molecules [4, 5, 6, 9]. It also has numerous applications in the vast field of complex networks [7, 8, 13, 14, 17]. A number of properties especially lower and upper bounds [3, 10, 11, 12, 15, 16, 18, 19, 20] for the Estrada index are known. In this paper, we establish further lower bounds improving some res...

Lower Bounds for Estrada Index

If G is an (n,m)-graph whose spectrum consists of the numbers λ1, λ2, . . . , λn, then its Estrada index is EE(G) = ∑n i=1 e λi . We establish lower bounds for EE(G) in terms of n and m. Introduction In this paper we are concerned with simple graphs, that have no loops and no multiple or directed edges. Let G be such a graph, and let n and m be the number of its vertices and edges. Then we say ...

Lower bounds for the Estrada index

Lower bounds of Copson type for the transpose of matrices on weighted sequence spaces