Let us define the following matrix: $C=AB$ where $B$ is a block diagonal matrix with $N$ blocks, $B_1$, $B_2$ … $B_N$, each of dimensions $M \times M$. I know that $B_k = I_M – \mu R_k$ with $R_k$ equals to a hermitian matrix and $\mu$ some positive constant. Moreover, I know that the the entries … Read more
Denote by $\circ$ the Kronecker product, let $|\cdot|$ denote the matrix/vector of absolute values, and let $e$ be the vector of all ones. Comparison is entrywise, i.e., $y \ge x$ is equivalent to $y_i \ge x_i$ for all $I$. Problem 1: Let $A$ be a real $n\times n$ matrix, $n>1$, and assume $$ (A \circ … Read more
Let $A$ be a real square matrix of size $n \times n$. Is there an upper bound on the minimum spectral norm under diagonal similarity, i.e., $$ s(A) = \min_{D} \lVert D^{-1} A D\rVert_2, $$ where $D$ is a non-singular, diagonal real matrix. Also, is there are a relation between $s(A)$ and the spectral radius … Read more
Let Bn denote the set of n×n matrices with entries in {0,1}. It follows from the spectral radius formula that if M∈Bn is not nilpotent, then ρ(M), the spectral radius of M, is ≥1. I need a condition for ρ(M)>1 in terms of the proportion of 1s. QUESTION. Is there a c∈(0,1) such that for … Read more
I encountered an inequality when reading a paper. Can someone help to show how to prove it? Let be the spectral radius of matrix $A$ or $\rho(A)=\max\{|\lambda|, \lambda \text{ are eigenvalues of matrix }A\}$. For matrices $S$ and $T$ with positive spectral radii, and two arbitrary real positive numbers $a$ and $b$, such that $\rho(S) … Read more
We need a help to find a reasonable condition such that the spectral radius for a special matrix $\mathbf{J} \otimes\hat{\mathbf{G}}\hat{\mathbf{W}} + \mathbf{I}\otimes\mathbf{\hat{H}}$ is smaller than 1. Here $\otimes$ is tensor product. These matrices $\bf J$, $\hat{\bf{G}}$, $\hat{\bf{H}}$ are defined below. I am thinking about if there is a matrix norm $\|\|$ such that $\|\mathbf{J} \otimes\hat{\mathbf{G}}\hat{\mathbf{W}} … Read more
Consider the space $$ S = \left\{ A \in \mathbb{R}^{n \times n} : \mathrm{SpectralRadius}(|A|) \leq 1 \right\}$$ where $|A|$ is the entry-wise absolute value. Given a matrix $M \in \mathbb{R}^{n\times n}$ such that $M \not \in S$. Is there a way to solve $$\arg\min_{\hat M \in S} \Vert M – \hat M \Vert$$ for some … Read more
I would like to know which is the spectral radius of this n×n matrix: 01…110…0…………10…0 I know that the spectral radius is the maximum eigenvalue, but I don’t know how to calculate it in this matrix… I also know that if we’ve got a symmetric amtrix the spectral radius is ||A||2 but I neither know … Read more
a) Prove using Schur decomposition \lim_{n \rightarrow \infty}||A^n||=0 \iff p(A)<1 where A is in \mathbb{C}^{mxm} and p is the spectral radius. b) \lim_{t \rightarrow \infty}||e^{At}||=0 \iff a(A)<1 where A is in \mathbb{C}^{mxm} and a is the spectral abscissa. My thoughts are as follows. For (a), I think that \lim_{n \rightarrow \infty}||A^n||=0 will only happen if … Read more
Suppose A and B have the same spectral radius ρ. We can find a norm ‖ s.t. \|A\|_A – \epsilon < \rho. We can likewise find a another norm s.t. \|B\|_B – \epsilon < \rho. Under what conditions can we find a norm \|\cdot\|_* such that both \|A\|_* – \epsilon < \rho and \|B\|_* – … Read more
