Timeline for Test functions with small support and nonnegative Fourier transform
Current License: CC BY-SA 3.0
3 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 28, 2012 at 16:05 | vote | accept | user25235 | ||
| Oct 28, 2012 at 16:05 | |||||
| Oct 28, 2012 at 16:04 | comment | added | user25235 | An unexpectedly simple solution ; thanks ! I think this still applies in the noncommutative case (the Haar measure is left and right invariant) : If $VV \subset U$, $g_1$ is any map vanishing outside $V$, with nonzero mean, and $g_2 : x \mapsto g_1^{*}(x^{-1})$, then $f = g_1 \star g_2$ should work. | |
| Oct 28, 2012 at 15:31 | history | answered | Abdelmalek Abdesselam | CC BY-SA 3.0 |