Timeline for Some problems about symmetric convolution semigroup on the unit circle
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 2, 2016 at 7:35 | comment | added | yangmengqh | But how to prove this case? | |
| Feb 2, 2016 at 0:12 | comment | added | Fedor Petrov | For proving 1), it suffices to consider $\lambda_n=\min(|n|,M)$ for fixed positive integer $M$. Any other concave increasing sequence is a positive linear combination of such sequences. | |
| Feb 2, 2016 at 0:10 | comment | added | Fedor Petrov | 2) follows from 1). Indeed, pointwise product of positive semidefinite matrices $A,B$ is again p.d., hence so are $A^k$ for $k\geq 0$ and $e^{tA}$ for $t>0$. | |
| Feb 1, 2016 at 19:10 | history | asked | yangmengqh | CC BY-SA 3.0 |