Timeline for Attaching an ideal whose square is zero: does this operation have a name and a notation?
Current License: CC BY-SA 3.0
22 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 10, 2022 at 12:17 | answer | added | user494529 | timeline score: 1 | |
| May 18, 2016 at 7:28 | comment | added | chizhek | @Fred Rohrer - Yes, that's where I saw it! Thank you. | |
| May 17, 2016 at 19:49 | comment | added | Fred Rohrer | Dear chizhek, maybe you saw it in Lam's Lectures on Modules and Rings, where it is introduced on page 37 under the name of "trivial extension". | |
| May 17, 2016 at 13:16 | vote | accept | chizhek | ||
| May 17, 2016 at 13:05 | history | edited | chizhek | CC BY-SA 3.0 |
Improved a wording of a definition.
|
| May 17, 2016 at 12:49 | history | edited | Frieder Ladisch |
Added one arXiv-tag
|
|
| May 17, 2016 at 12:47 | comment | added | Frieder Ladisch | This ring $ A\ltimes N$ can also be realized as a subring of a triangular ring, namely $$ \left\{ \begin{pmatrix} a & n \\ & a \end{pmatrix} \colon a \in A, n\in N \right\} .$$ | |
| May 17, 2016 at 12:24 | history | edited | chizhek | CC BY-SA 3.0 |
Improved some formulations. Chosen better line breaks (to improve readability).
|
| May 17, 2016 at 12:16 | history | edited | chizhek | CC BY-SA 3.0 |
Improved some formulations. Chosen better line breaks.
|
| May 17, 2016 at 10:16 | history | edited | chizhek | CC BY-SA 3.0 |
Two corrections.
|
| May 17, 2016 at 10:11 | history | edited | chizhek | CC BY-SA 3.0 |
Expanded the question, by a proposed definition of a semidirect product for rings instead of groups.
|
| May 17, 2016 at 7:40 | comment | added | chizhek | @Fred Rohrer - Thank you, found it. Though this is not where I saw it before. I believe it was somewhere in Tsit Yuen Lam's "A First Course in Noncommutative rings", but for the life of me cannot locate it. | |
| May 17, 2016 at 7:14 | history | edited | chizhek | CC BY-SA 3.0 |
Cut out the second part of the question, to repost it on meta.mathoverflow.net.
|
| May 16, 2016 at 21:26 | comment | added | Fred Rohrer | Bourbaki treats this construction in A.II.1 Exercice 7, but does introduce neither name nor notation for it. | |
| May 16, 2016 at 20:52 | answer | added | John Rognes | timeline score: 5 | |
| May 16, 2016 at 18:00 | answer | added | Jeremy Rickard | timeline score: 2 | |
| May 16, 2016 at 17:48 | history | edited | Yemon Choi |
added some tags which looked relevant
|
|
| May 16, 2016 at 17:47 | comment | added | Yemon Choi | This kind of construction has appeared in many papers on Banach algebras, many of which IMO are reinventing the wheel, even if I can't pin down where the wheel came from. For algebras over a field, I think it might be mentioned explicitly in Hochschild's papers from the 1940s, since it is precisely the extension of A by N that corresponds to the zero cocycle in H^2(A,N) | |
| May 16, 2016 at 17:03 | comment | added | chizhek | @Anthony Quas - Stupid me: meta.mathoverflow.net gets me there. I am hurrying home right now. Tomorrow I will cut the second part of the question out and repost it on the meta site. Thanks. | |
| May 16, 2016 at 17:00 | comment | added | chizhek | @Anthony Quas - I think so. I would rather post it there, it is inappropriate here. But when you are in pain, you don't care for appropriate manners, you just cry out... How do I get there, to meta.mathoverflow.net? Below on this page there is only the link to Meta Stack Exchange. | |
| May 16, 2016 at 16:44 | comment | added | Anthony Quas | I'm not sure - is the second part of the question appropriate for meta.mathoverflow.net? | |
| May 16, 2016 at 16:00 | history | asked | chizhek | CC BY-SA 3.0 |