Timeline for Find a "natural" group that contains the quotient of the infinite symmetric group by the alternating subgroup
Current License: CC BY-SA 4.0
20 events
| when toggle format | what | by | license | comment | |
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| May 31, 2022 at 8:06 | history | edited | Martin Sleziak | CC BY-SA 4.0 |
a minor typo
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| Feb 25, 2019 at 22:42 | answer | added | YCor | timeline score: 9 | |
| Feb 25, 2019 at 22:11 | history | edited | YCor | CC BY-SA 4.0 |
rewrote title to reflect the actual question; changed tags
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| Jan 20, 2010 at 1:08 | comment | added | Martin Brandenburg | well, computers can't understand the concern, but maybe a mathematician. | |
| Jan 19, 2010 at 19:02 | comment | added | S. Carnahan♦ | -1. What precisely do you mean by "write down a homomorphism" from permutations on an infinite set? Is the regular permutation embedding of your quotient no good? | |
| Jan 19, 2010 at 18:15 | history | edited | Martin Brandenburg | CC BY-SA 2.5 |
added 11 characters in body; edited tags
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| Jan 19, 2010 at 18:13 | comment | added | Mariano Suárez-Álvarez | "Signum function" is perfectly good English, but is used, as far as I know, to refer to the function $\mathrm{sgn}:\mathbb R\to\{-1,0,1\}$ that we all know from Calculus. | |
| Jan 19, 2010 at 17:46 | history | edited | Martin Brandenburg | CC BY-SA 2.5 |
added 88 characters in body; added 86 characters in body; added 126 characters in body
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| Jan 19, 2010 at 17:44 | comment | added | Martin Brandenburg | perhaps I should take another english course :) | |
| Jan 19, 2010 at 17:39 | answer | added | Reid Barton | timeline score: 11 | |
| Jan 19, 2010 at 17:33 | history | edited | Martin Brandenburg | CC BY-SA 2.5 |
edited body
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| Jan 19, 2010 at 12:58 | history | edited | Martin Brandenburg | CC BY-SA 2.5 |
deleted 6 characters in body; edited title
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| Jan 19, 2010 at 12:57 | answer | added | Pete L. Clark | timeline score: 22 | |
| Jan 19, 2010 at 11:54 | history | edited | Harry Gindi |
edited tags
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| Jan 19, 2010 at 11:11 | answer | added | Kevin Buzzard | timeline score: 16 | |
| Jan 19, 2010 at 11:03 | comment | added | Kevin Buzzard | And "reminds on the signum" probably means that he wants the extension to S_infty to have a definition which is reminiscent of the definition of "sign" on G. | |
| Jan 19, 2010 at 11:02 | comment | added | Kevin Buzzard | "signum" sounds to me like the kind of thing a native German speaker might call "sign" (of a permutation). The question seems pretty clear to me. S_infty contains the subgroup G of permutations that only move finitely many elements. Such permutations have a sign. That gives us a map s:G-->Z/2. The OP claims there's no group hom S_infty-->Z/2 that extends s, and wants to know whether there's an "explicit" group hom s:S_infty-->(some group containing Z/2) that restricts to s. And he doesn't want an argument of the form "by Zorn's Lemma blah blah done", he wants an explicit construction. | |
| Jan 19, 2010 at 10:58 | history | edited | Kevin Buzzard | CC BY-SA 2.5 |
mathds didn't work for me (KB); I changed it to mathbf.
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| Jan 19, 2010 at 9:51 | comment | added | Thorny | Could you clarify the question a bit? In particular, what do you mean by a homomorphism that "restricts to the signum"? | |
| Jan 19, 2010 at 8:43 | history | asked | Martin Brandenburg | CC BY-SA 2.5 |