We consider the problem of reconstructing an cell matrix constructed from a vector of positive real numbers, from a given set of spectral data. In addition, we show that the spectra of cell matrices and are the same for every permutation .
The study on limit points of eigenvalues of undirected graphs was initiated by A. J. Hoffman in 1972. Now we extend the study to digraphs. We prove: 1. Every real number is a limit point of eigenvalues of graphs. Every complex number is a limit point of eigenvalues of digraphs. 2. For a digraph , the set of limit points of eigenvalues of iterated subdivision digraphs of is the unit circle in the complex plane if and only if has a directed cycle. 3. Every limit point of eigenvalues of a set...
We propose a new localization result for the leading eigenvalue and eigenvector of a symmetric matrix . The result exploits the Frobenius inner product between and a given rank-one landmark matrix . Different choices for may be used, depending on the problem under investigation. In particular, we show that the choice where is the all-ones matrix allows to estimate the signature of the leading eigenvector of , generalizing previous results on Perron-Frobenius properties of matrices with...
By a hollow symmetric matrix we mean a symmetric matrix with zero diagonal elements. The notion contains those of predistance matrix and Euclidean distance matrix as its special cases. By a centered symmetric matrix we mean a symmetric matrix with zero row (and hence column) sums. There is a one-toone correspondence between the classes of hollow symmetric matrices and centered symmetric matrices, and thus with any hollow symmetric matrix D we may associate a centered symmetric matrix B, and vice...