Timeline for Is the crossed product $\mathcal{K} \rtimes G$ a groupoid algebra?
Current License: CC BY-SA 3.0
14 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 11, 2017 at 17:34 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Dec 12, 2016 at 17:05 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Nov 12, 2016 at 16:23 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Oct 13, 2016 at 21:48 | comment | added | Ruy | Depending on what you want to do, describing a C*-algebra as a twisted groupoid C"-algebra is often good enough. So @Ozawa's last comment could be what you need. | |
| Oct 13, 2016 at 15:48 | answer | added | Nicolas Boerger | timeline score: 6 | |
| S Jul 14, 2014 at 15:50 | history | bounty ended | CommunityBot | ||
| S Jul 14, 2014 at 15:50 | history | notice removed | CommunityBot | ||
| S Jul 6, 2014 at 14:24 | history | bounty started | SiOn | ||
| S Jul 6, 2014 at 14:24 | history | notice added | SiOn | Draw attention | |
| Jul 1, 2014 at 23:03 | comment | added | SiOn | yes, even not clear for finite groups(for trivial group its obvious only)! | |
| Jul 1, 2014 at 22:03 | comment | added | Narutaka OZAWA | You are right. It was isomorphic to ${\mathcal K}\otimes\mathrm{C}^*_\lambda(G,\bar{\omega})$. It isn't clear if it's a groupoid $\mathrm{C}^*$-algebra. | |
| Jul 1, 2014 at 20:32 | comment | added | SiOn | @NarutakaOZAWA if you look at this paper arxiv.org/pdf/math/0609784v2.pdf (page 5, second paragraph from top), this action by $G$ comes from a 2-cocycle from 2nd cohomology group of $G$, and the crossed product $\mathcal{K} \rtimes G$ highly depends on that cocycle. So can you please clarify the 1st statement? | |
| Jun 30, 2014 at 21:47 | comment | added | Narutaka OZAWA | Since all automorphisms of $\mathcal K$ are inner, the crossed product ${\mathcal K} \rtimes G$ is $*$-isomorphic to ${\mathcal K} \otimes \mathrm{C}^*_\lambda(G)$. The latter is a groupid $\mathrm{C}^*$-algebra. | |
| Jun 27, 2014 at 12:31 | history | asked | SiOn | CC BY-SA 3.0 |