Timeline for Conditions for when an off-centre ellipsoid fits inside the unit ball
Current License: CC BY-SA 3.0
9 events
| when toggle format | what | by | license | comment | |
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| May 23, 2017 at 12:37 | history | edited | CommunityBot |
replaced http://stackoverflow.com/ with https://stackoverflow.com/
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| Aug 26, 2013 at 3:59 | history | edited | Ricardo Andrade | CC BY-SA 3.0 |
added top level tag
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| Aug 26, 2013 at 3:46 | answer | added | fedja | timeline score: 3 | |
| Aug 25, 2013 at 17:23 | answer | added | Robert Bryant | timeline score: 4 | |
| Aug 25, 2013 at 15:06 | answer | added | Wlodek Kuperberg | timeline score: 2 | |
| Aug 25, 2013 at 11:54 | comment | added | Wlodek Kuperberg | Your problem for the ellipse (the 2D case) can be solved analytically, since it leads to a polynomial equation of degree 4, but in higher dimensions finding the most distant point analytically is probably impossible. However, if you just want a "yes-or-no" answer to "is the ellipsoid contained in the ball?", without locating the point, then perhaps it is possible, but could be very hard already in 3D. | |
| Aug 25, 2013 at 5:06 | comment | added | Noam D. Elkies | There are natural questions in "basic Euclidean geometry" that lead to complicated equations that don't have simple solutions. For example, given $5$ general conics $C_1,\ldots,C_5$ in the plane there's finitely many conics $C$ tangent to all of them, but in general finding $C$ requires solving an equation of degree $3264$ $-$ and even the determination of the degree is nontrivial, never mind the equation! See isites.harvard.edu/fs/docs/icb.topic720403.files/book.pdf | |
| Aug 25, 2013 at 2:37 | answer | added | Wlodek Kuperberg | timeline score: 2 | |
| Aug 25, 2013 at 1:06 | history | asked | Antony | CC BY-SA 3.0 |