Timeline for Does the matrix exponential preserve the positive-semi-definite ordering?
Current License: CC BY-SA 3.0
12 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jul 1, 2014 at 9:31 | vote | accept | nikka | ||
| Jun 30, 2014 at 19:39 | comment | added | Neil Strickland | @Suvrit: I am glad that you have written an answer, which makes it unlikely that the question will be closed, and so makes my comment less pressing. But I will say for the record: responses that simply provide a missing "magic keyword" can be extremely useful, and questions should certainly not be closed just because they can be answered in that way. | |
| Jun 30, 2014 at 18:58 | answer | added | Suvrit | timeline score: 23 | |
| Jun 30, 2014 at 18:35 | comment | added | Suvrit | @Dmitry: I did not say "It is well-known..." is the reason for the answer; my reason was the fact that Andreas has provided the magic keyword "operator monotone" googling which the answer becomes apparent (e.g., by reading the Wikipedia entry that shows up on searching "operator monotone matrix exponential"). Since it seems that others care about this question, I'll pen down an answer with some additional useful information that people may appreciate. | |
| Jun 30, 2014 at 18:21 | comment | added | Dmitry Savostyanov | @Suvrit "It is well-known that..." does not really answer the question, it just states that the answer is well known (to someone). | |
| Jun 30, 2014 at 18:12 | comment | added | Todd Trimble | To me as well. It might be "well-known" to the right people, but I doubt it's standardly known across the whole community. (I didn't know it, anyway.) | |
| Jun 30, 2014 at 17:59 | comment | added | Anthony Quas | seems like a reasonable question to me. | |
| Jun 30, 2014 at 17:47 | review | Close votes | |||
| Jun 30, 2014 at 23:14 | |||||
| Jun 30, 2014 at 17:36 | answer | added | Robert Israel | timeline score: 13 | |
| Jun 30, 2014 at 17:34 | comment | added | Suvrit | Andreas has already answered the question fully in his comment; am voting to close as this is not a research level question. best, | |
| Jun 30, 2014 at 16:17 | comment | added | Andreas Thom | Functions with this property are called "operator monotone". It is well-known that $\log$ is operator-monotone, but squaring or exponentiating ist not. | |
| Jun 30, 2014 at 16:12 | history | asked | nikka | CC BY-SA 3.0 |