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18 votes
2 answers
5k views

Minimum off-diagonal elements of a matrix with fixed eigenvalues

I am an engineer working in radar research. I came accross a problem on which I cannot seem to find literature. I can ask it in two different ways. Perhaps depending on the reader, the alternative ...
mermeladeK's user avatar
6 votes
2 answers
438 views

Can a perturbation of a matrix product always be represented as product of perturbations of its factor matrices?

Given $A=BC$ where $A\in\mathbb{R}^{m\times n}$ and for some $B\in\mathbb{R}^{m\times k}, C\in\mathbb{R}^{k\times n}$. We assume that $k>=\min(m,n)$ so that this decomposition always exists for any ...
jayki's user avatar
  • 135
6 votes
1 answer
371 views

Separating the spectrum of a Hermitian matrix

Given Hermitian matrix $A$, I would like to perturbate it so that its eigenvalues become well-separated. Specifically, let $A$ be some Hermitian matrix, and let $G$ be a Gaussian matrix, with each ...
Lior Eldar's user avatar
1 vote
1 answer
1k views

Spectral radius's relation with row sum

Let $A$ be a non-negative $N \times N$ square matrix with $a_{i,i}=0, 1 \leq i \leq N$. Also, let $r_i$ be the $i$-th row sum of $A$. I know that $\rho(A)$, the spectral radius of $A$, is bounded as ...
Val K's user avatar
  • 355
0 votes
1 answer
568 views

Perturbation theory for matrices

I encountered the following problem. Since this is somewhat not related to what I normally do, I wanted to know what the best estimates in this field are. Let $A \in \mathbb{R}^{n \times n}$ be a ...
Michel's user avatar
  • 3