Timeline for Crossed products and unitaries implementing $\mathbb{Z}_n$-actions
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 20, 2017 at 16:29 | history | edited | Ulrich Pennig | CC BY-SA 3.0 |
added details about crossed product
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| Aug 20, 2017 at 16:19 | vote | accept | worldreporter | ||
| Aug 20, 2017 at 16:19 | comment | added | worldreporter | All right! I think I get it now. Tanks a lot! | |
| Aug 20, 2017 at 15:58 | comment | added | Ulrich Pennig | Note that $t$ is not an element of $A$, i.e. the automorphism does not have to be inner from the start. However, the crossed product is defined in such a way that the automorphism becomes inner by adding another element $t$ that satisfies $tat^* = \alpha(a)$. | |
| Aug 20, 2017 at 15:54 | comment | added | worldreporter | Thanks for your answer! I see that if we have a $t$ such that $tat^*=\alpha(a)$ elements of the above polynomial form are exactly the elements of the crossed product. But why is every automorphism of this form? Is this a general property of the multiplier algebra? | |
| Aug 20, 2017 at 12:54 | history | answered | Ulrich Pennig | CC BY-SA 3.0 |