Timeline for Subgroup of p-adic units

Current License: CC BY-SA 4.0

16 events

when toggle format	what		by	license	comment
Mar 19 at 15:51	comment	added	Antonius		But $\widehat{\mathbb{Z}^\times}$ is.
Mar 19 at 14:40	comment	added	Chris Wuthrich		Don't worry, I think there was no danger that you are misunderstood. Similarly $\mathbb{Z}_p^{\times}$ is not the $p$-adic completion of $\{\pm1\}$.
Mar 19 at 14:23	history	edited	Antonius	CC BY-SA 4.0	added 10 characters in body
Mar 19 at 14:22	comment	added	Antonius		No, the times is correct, otherwise we have the profinite completion of the unit group of $\mathbb Z$, which is $\{\pm 1\}$. I have put brackets around the ring, to make it clear, what I mean.
Mar 18 at 17:07	history	became hot network question
Mar 18 at 13:43	history	edited	gmvh	CC BY-SA 4.0	Removed extra "is"
Mar 18 at 13:09	comment	added	LSpice		TeX note: $\widehat{\mathbb Z}^\times$ `\widehat{\mathbb Z}^\times` puts the `\times` too high. To get it at the proper level, you can `\smash` the `\widehat{\mathbb Z}` to force TeX to forget its height: $\smash{\widehat{\mathbb Z}}^\times$ `\smash{\widehat{\mathbb Z}}^\times`. I have edited accordingly.
Mar 18 at 13:09	history	edited	LSpice	CC BY-SA 4.0	`\smash`
Mar 18 at 11:22	vote	accept	Antonius
Mar 18 at 11:11	answer	added	GH from MO		timeline score: 5
Mar 18 at 10:47	history	edited	YCor		edited tags
Mar 18 at 10:43	history	edited	Antonius	CC BY-SA 4.0	added 44 characters in body
Mar 18 at 10:00	comment	added	Antonius		Sorry, I meant dense in the unit group, not the ring. I am not sure, whether a similar argument applies for the unit group.
Mar 18 at 9:51	history	edited	Antonius	CC BY-SA 4.0	added 7 characters in body
Mar 18 at 9:32	comment	added	YCor		A subgroup is dense iff it is contained in $\ell\widehat{\mathbf{Z}}$ for no prime $\ell$. Given this, you should be able to answer your question.
Mar 18 at 9:06	history	asked	Antonius	CC BY-SA 4.0

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