In the recent years, the trace norm of graphs has been extensively studied under the name of graph energy. The trace norm is just one of the Ky Fan k-norms, given by the sum of the k largest singular values, which are studied more generally in the present paper. Several relations to chromatic number
Edge addition, singular values, and energy of graphs and matrices
โ Scribed by Saieed Akbari; Ebrahim Ghorbani; Mohammad Reza Oboudi
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 135 KB
- Volume
- 430
- Category
- Article
- ISSN
- 0024-3795
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โฆ Synopsis
The energy of a graph/matrix is the sum of the absolute values of its eigenvalues. We investigate the result of duplicating/removing an edge to the energy of a graph. We also deal with the problem that which graphs G have the property that if the edges of G are covered by some subgraphs, then the energy of G does not exceed the sum of the subgraphs' energies. The problems are addressed in the general setting of energy of matrices which leads us to consider the singular values too. Among the other results it is shown that the energy of a complete multipartite graph increases if a new edge added or an old edge is deleted.
๐ SIMILAR VOLUMES
With the help of the undirected graph of a matrix we establish new theorems for estimating the singular values. The location of singular values of a matrix A is described in terms of its deleted absolute row sums and column sums. The formulation has an appearance analogous to Brauer's and Brualdi's