Timeline for Question about "wide" random matrices
Current License: CC BY-SA 2.5
9 events
| when toggle format | what | by | license | comment | |
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| Sep 5, 2010 at 5:40 | vote | accept | umar | ||
| Sep 4, 2010 at 7:12 | vote | accept | umar | ||
| Sep 4, 2010 at 7:12 | |||||
| Sep 3, 2010 at 20:09 | answer | added | umar | timeline score: 2 | |
| Sep 3, 2010 at 11:21 | answer | added | Bob Durrant | timeline score: 1 | |
| Sep 3, 2010 at 10:11 | comment | added | J. M. isn't a mathematician |
umar: An $m\times n$ matrix has $\min(m,n)$ singular values.
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| Sep 3, 2010 at 8:02 | comment | added | umar | J.M. -- Thanks. I don't understand your claim that $\phi(A) = \sigma_{min}(A^T)$ when $m < n$. Isn't it the case that $\sigma_{min}(A^T) = \sigma_{min}(A)$? So doesn't my $m = 1$ and $n > 1$ counterexample still apply? | |
| Sep 3, 2010 at 6:20 | comment | added | J. M. isn't a mathematician | "although I am not certain why this is true" - books on numerical linear algebra devote a paragraph or two to this, since this is related to the discussion of the conditioning of least squares problems. | |
| Sep 3, 2010 at 6:19 | comment | added | J. M. isn't a mathematician | For $m<n$, $\sigma_{\min}$ of $A^T$ is your $\phi$. | |
| Sep 3, 2010 at 5:27 | history | asked | umar | CC BY-SA 2.5 |