@MartinSleziak I fixed the "Front" link in my answer, which was more of a search for a specific author, but took the opportunity to fix some other links in other answers there, too. In particular, Springer's internal links (from springer.com to Springerlink) to LNM volumes are broken, so I had to bypass that.
I have notice an edit in 2017 with the edit summary "corrected broken link (this arxiv's mirror is not in operation for several weeks)". So this is not the first time there is a similar problem. — Martin Sleziak30 secs ago
I am teaching an introductory group theory course, and it has come to the inevitable proof that $A_n$ is simple for $n\geq 5$. Now, there seem to be a number of proofs that I can find – one the "standard" one with $3$-cycles, and the others using primitivity or conjugacy class size estimation. Do...
I am teaching an introductory group theory course, and it has come to the inevitable proof that $A_n$ is simple for $n\geq 5$. Now, there seem to be a number of proofs that I can find – one the "standard" one with $3$-cycles, and the others using primitivity or conjugacy class size estimation. Do...
@MartinSleziak I added a few tags: symmetric group (because simplicity of the derived subgroup is a result on the symmetric group), and alternative proof to follow your suggestion. I didn't add permutation group which I think is unnecessary to add to every question on the symmetric group.
I also changed the "almost ring theory" link to its (heh) almost certain target; it looks like maybe there was a spurious '5' in the link that prevented it from being an arXiv identifier, so I thought it was worth editing in light of @MartinSleziak's recent meta post on the arXiv front-end. — LSpice10 hours ago
deprecated-tags I will just remind that mods can merge tags without any bumping. So if at some point we will reach the state that all question tagged abstract-algebra are questions where gr.group-theory fits, mods can change the tags without bumping any questions.
deprecated-tags Alternatively a tag could be burninated, which removes all instances of the tag without any bumping. (This cannot be done by mods. However, MO mods sometimes used merging into tag-removed as a replacement.)
If some merging should be made, it would rather be ra.rings-and-algebras, which in a sense is more generic than the other two. I might then retag the group theory questions currently tagged abstract-algebra then, and more generally those for which [ra.rings-and-algebras] wouldn't fit too well. (Tagging ra-rings.and.algebras questions of pure commutative algebra being a minor side effect.)
One question in any case is whether any mod is currently prone to deal with retagging. François Dorais used to do so but seems to have his last activity in the "help cleanup tags" thread in March 2019, in spite of many pending requests (including some obvious ones).
Todd Trimble expressed interest to be more involved in tag-related issues at some point. However, it was back in 2018, I am not sure whether he is still interest.
Looking at the list of tag-synonyms, many of them were created by François G. Dorais.
@YCor I suppose that retagging abstract-algebra might take several months before it is cleaned-up sufficiently for merging. So it is more important whether the moderators will be active after that happens.
However, I believe they at least read meta. (And, in addition to that, mods get notification about each new question on meta into their moderator inbox.)
So I suppose that a reasonable thing to do would be to make a post on meta. (When the abstract-algebra tag - or some other deprecated tag - is cleaned-up enough to consider merging.)
It seems that I have basically repeated some things which I said here before: chat.stackexchange.com/transcript/10243/2019/1/24 Although this time we are mostly interested in activity of moderators.
In Theorem 7.4 of the paper "patching and the p-adic Langlands program for GL2(Qp)", https://arxiv.org/pdf/1609.06902.pdf, it is proved that in the minimally ramified case, the completed homology of given level is the completed tensor of the dual family of Banach representation (denoted as $\til...
Given the discussion, I tend to be gradually convinced that creating small-uncountable-cardinals is a good idea, and a good counterpart to the existing quite broad large-cardinals, which currently has almost 500 occurrences. I initially expressed that all this could be embedded into continuum-hyp...
> Edit (April 2020)
> Finally a majority led to create cardinal-characteristics about 13 months ago, with at this date 38 questions including 10 older ones that were retagged.
> The use of this tag seems consistent and I'm finally convinced it was a good idea and that my reluctance was excessive.
I'm confused Decoupling theory probably it is anciant theory in mathematics but no enough backgrounds on it either in wiki or mathworld , And also I accrossed this theory on Tao Blog here , Now I ask why in mathoverflow there is no tag about this theory like homotopy and others theories ?
I'm confused Decoupling theory probably it is anciant theory in mathematics but no enough backgrounds on it either in wiki or mathworld , And also I accrossed this theory on Tao Blog here , Now I ask why in mathoverflow there is no tag about this theory like homotopy and others theories ?
