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12:18 AM
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A: Tag management 2023

Ulysse KellerI think that at least 1 new tag for questions based on Bourbaki's math' treatises is needed, especially for their measure theory which is practically another subject than what is found under that title elsewhere. This is not always a problem, but it can be, due to different definitions - one can ...

 
 
5 hours later…
4:57 AM
Questions where the tag was added/removed (including the editors): data.stackexchange.com/math/query/1105163/… data.stackexchange.com/math/query/1038474/…
The tag was mentioned here several times, you can find some questions that had this tag here in chat: chat.stackexchange.com/search?room=3740&q=bourbaki
The tag was created and removed in 2015 - a single question: math.stackexchange.com/posts/994986/revisions
There were several questions in 2016 - and a related post on meta: math.meta.stackexchange.com/a/22983
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A: Tag management 2016

Asaf Karagila Resolved: manually removed from all questions. The tag bourbaki is entirely useless. It gives nothing that searching "Bourbaki" doesn't already do.

The tag (bourbaki) was created and removed in the past, I have posted some statistics in the Tagging chatroom. There is a related post in an older tag management thread. (And there was a separate question today - now deleted: I want at least one new tag for questions specific to Bourbaki's math' treatises, especially measure theory.) — Martin Sleziak 2 mins ago
 
 
2 hours later…
7:22 AM
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Q: What is Casimir tensor corresponding to a non-degenerate invariant bilinear form?

Anil Bagchi.Let $\mathfrak {g}$ be a semisimple Lie algebra with a non-degenerate invariant bilinear form $B$ (e.g. Killing form). Then what is meant by saying that $C$ is a Casimir tensor with respect to the bilinear form $B\ $? The wikipedia article on Casimir element says the following $:$ Given a basis $...

In mathematics, a Casimir element (also known as a Casimir invariant or Casimir operator) is a distinguished element of the center of the universal enveloping algebra of a Lie algebra. A prototypical example is the squared angular momentum operator, which is a Casimir element of the three-dimensional rotation group. More generally, Casimir elements can be used to refer to any element of the center of the universal enveloping algebra. The algebra of these elements is known to be isomorphic to a polynomial algebra through the Harish-Chandra isomorphism. The Casimir element is named after Hendrik...
A new tag with three questions.
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Q: Morphisms of ringed spaces from the point of view of the étale space

Elías Guisado Villalgordo$\def\sO{\mathcal{O}} \def\sA{\mathcal{A}} \def\sB{\mathcal{B}} \def\sF{\mathcal{F}} \def\sG{\mathcal{G}} \def\et{\operatorname{\acute Et}} \def\shtop{\mathsf{ShTop}} \def\etl{\mathsf{\acute Etale}} $A morphism of ringed spaces $(X,\sO_X)\to(Y,\sO_Y)$ can be defined to be a continuous map $\varph...

2
Q: Equivalence of categories between étale spaces and sheaves of sets over a topological space. Where to find a proof?

Elías Guisado Villalgordo$\def\et{\operatorname{\acute Et}} \def\sh{\operatorname{Sh}} \def\set{\mathsf{Set}} \def\top{\mathsf{Top}} \def\psh{\operatorname{PSh}} $From a google search, it appears to be a well-known fact that there is an equivalence of categories $\et(X)\simeq\sh_\set(X)$, where $X$ is a topological space...

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Q: More details in the proof of the equivalence of categories between vector bundles over a smooth manifold and locally free sheaves

Elías Guisado Villalgordo$\def\VB{\mathsf{VB}} \def\sO{\mathcal{O}} \def\Mod{\mathsf{Mod}} \def\LFMod{\mathsf{LFMod}}$For a ringed space $(X,\sO_X)$ and a ring $R$, denote $\Mod(\sO_X)$ and $\Mod(R)$ to the categories of $\sO_X$-modules and of $R$-modules. Let $M$ be a smooth manifold and denote $\sO_M$ to the sheaf of s...

In category theory, a branch of abstract mathematics, an equivalence of categories is a relation between two categories that establishes that these categories are "essentially the same". There are numerous examples of categorical equivalences from many areas of mathematics. Establishing an equivalence involves demonstrating strong similarities between the mathematical structures concerned. In some cases, these structures may appear to be unrelated at a superficial or intuitive level, making the notion fairly powerful: it creates the opportunity to "translate" theorems between different kinds of...
@MartinSleziak I have edited that question and removed the tag .
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Q: Prove That PDF is ≥ 0 for all real numbers

oatmilkunicornI am taking my first stats course and struggling quite a bit as my professor does not explain things well. I wanted to double check that I am on the right track. My question is: Show that $f(x)≥0$ for all $x ∈ R$ , where $x$ is the exponential density function:$$f(x) = \begin{cases}λ\operatornam...

 
 
7 hours later…
2:56 PM
@MartinSleziak the target of the last links (a now deleted question) was mine. After receiving a duplicate mention and realizing that I was supposed to enter my proposal here (and doing this) I deleted that myself. From another of your links, I found written: "The tag [bourbaki] is entirely useless. It gives nothing that searching "Bourbaki" doesn't already do". How is such a search done? Is it only finding Bourbaki when mentioned in a title? And who might do that? IMHO the same argument might apply to all tags ... so why tags at all? (continued) — Ulysse Keller 4 mins ago
I take the opportunity to mention that I did not find how to search for 2+ tags at the same time (combined with AND) Is this possible, if yes, how is it done? Same question for a tag and a non-tag word — Ulysse Keller 56 secs ago
Search for two tags is simple - for example here are the questions tagged general-topology and reference-request.
Similarly, you can simply add to a tag some other word - for example, posts tagged general-topology with the word Bourbaki.
@UlysseKeller The basics of searching are unrelated to the discussion here - in order to avoid a long discussion unrelated to this topic, I posted some examples of possible searches in chat. — Martin Sleziak 15 secs ago
For the record, if you search for bourbaki using the built-in-search, the results are post containing the word bourbaki - not only when bourbaki is mentioned in the title.
Some useful information about searching can be found in this FAQ post: How to search on this site?
 
 
5 hours later…
8:24 PM
I vaguely remember having read that for certain purposes in the Math. SE one has to install some special software; may-be it was for making such searches. At that time I didn't want to do such an installation - not feeling really a necessity at that time. Even now it might suffice to me that interested people can do it. But you talk about the built-in search ... doesn't that mean built-in in this website? If so, what is the recipe for this?
 
8:40 PM
Now I find the answer with title Built-in-search. It says the search bar is near the top of the site, so I made some trials ... and it worked! Thank you
 

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