Timeline for Cancellation theorem for direct and other kinds of products between groups
Current License: CC BY-SA 4.0
14 events
| when toggle format | what | by | license | comment | |
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| May 19, 2019 at 16:03 | history | edited | YCor | CC BY-SA 4.0 |
made title more specific
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| May 19, 2019 at 15:25 | review | Close votes | |||
| May 20, 2019 at 11:13 | |||||
| May 19, 2019 at 15:02 | 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. | |
| Apr 19, 2019 at 16:55 | review | Close votes | |||
| Apr 21, 2019 at 15:04 | |||||
| Apr 19, 2019 at 14:38 | answer | added | John McVey | timeline score: 3 | |
| Dec 14, 2011 at 11:44 | comment | added | Martin Brandenburg | I think the question is a little bit to vague and unfocused. | |
| Dec 14, 2011 at 8:04 | comment | added | Steve D | Here's a counterexample for knit products: mathforum.org/kb/… Of course, knit products and semidirect products are more general than direct products, so the counterexample you cited above works in both those cases as well. | |
| Dec 14, 2011 at 6:43 | comment | added | David Roberts♦ | Consider the maps of short exact sequences in the case of semidirect products... | |
| Dec 14, 2011 at 6:31 | comment | added | Ehsan M. Kermani | @Steve D: That's a good point! I mean, for each sides of the semi-product, and wreath product (which I'm not very familiar and comfortable with the latter one) | |
| Dec 14, 2011 at 6:25 | comment | added | Ehsan M. Kermani | @Yemon Choi: I tried for the semi-direct product of finite groups, but nothing came out! | |
| Dec 14, 2011 at 6:12 | comment | added | Steve D | Also, from the Grushko decomposition theorem, it would seem that for free products, cancellation is possible for finitely presented groups. | |
| Dec 14, 2011 at 6:03 | comment | added | Steve D | There's an inherent lack of symmetry in other products, like the semidirect product or wreath product. Which of the two subgroups involved would you like to cancel? I'm pretty sure there are counterexamples for either one though. | |
| Dec 14, 2011 at 5:58 | comment | added | Yemon Choi | Which of these various examples have you already tried? | |
| Dec 14, 2011 at 5:34 | history | asked | Ehsan M. Kermani | CC BY-SA 3.0 |