Tagging - 2019-12-16

Xander Henderson

3:10 AM

Should the transformation tag be deleted?

It seems like it is quite broad, and never really appropriate all by itself.

I don't see it being terribly useful to anyone...

Martin Sleziak

5:20 AM

new-tag A new tag applications-of-integration was created by Burt.

0

Q: Can work be negative?

Which of the following is the work done by a non-constant force $F (x) = x$ moving an object along the $x$‑axis from $2$ to $0$? I was given this problem. The correct answer is $-2$ because the integral is set up like: $\int^0_2$. But, can work really be negative?

Martin Sleziak

10:07 AM

The tag transformation seems to be around for quite a long time. SEDE: data.stackexchange.com/math/query/927958/… data.stackexchange.com/math/query/883845/…

Queries which show also editors who added/removed the tag: data.stackexchange.com/math/query/1105163/… data.stackexchange.com/math/query/1038474/…

It has been mentioned also here in chat chat.stackexchange.com/transcript/3740/2014/11/7 chat.stackexchange.com/transcript/3740/2014/11/9 and on meta:

1

A: Tag cleanup 2014

What is transformation about? No wiki. Questions involve: transformations of probability distributions transformations of differential equations transformation of conic section transformation matrices Fourier transform, Abel transform, Hilbert transform, Laplace transform, Legendre transform, ...

6

Q: What is the 'transformation' tag for?

Looking at the tags, I see that transformation tag is the first tag without a tag wiki. Upon further investigation I see questions that are barely related. Some of them are geometry related, some are to do with linear algebra and others are even to do with integration. Is this tag really construc...

discussion tagging tag-wikis

Based on this query, I get 114 question which have only this tag: data.stackexchange.com/math/query/131389/… (It was taken from here: How to find questions having only given tag (and no other tags)?)

It seems that the inquiry on meta lead at least to creation of tag-excerpt: math.stackexchange.com/posts/1012685/revisions

2

A: What is the 'transformation' tag for?

I wrote a tag excerpt pointing out the ambiguity of the term, and suggesting alternatives. I think that as long as the tag is used together with another tag, it is not a problem: e.g., in the combination probability-distributions transformation the second tag adds some information. I suggest e...

> Transformation has many meanings in mathematics. If using this tag, add another tag related to the object being transformed. If there is a tag for your specific kind of transformations, use that one instead: e.g., (laplace-transform), (fourier-analysis), (z-transform), (integral-transforms), (rigid-transformations).

I'd think that linear-transformations is worth keeping, but I am less sure about transformation.

2

Regardless of whether the tag is going to be removed or not, I think that the questions which have only this tag are worth retagging. (At least to add some additional tag(s), and maybe remove this one if it's not suitable.)

Arnaud D.

1:23 PM

The tag-wiki for trigonometric-series indicate that it should be used only for series of the form $\sum_n c_n e^{inx}$ or $\sum_n (a_n\sin(nx)+b_n\cos(nx))$. But in practice it seems to be often used for any series that involves a trigonometric function. I'm not sure what usage is best ; the more restricted one seems similar to fourier-series, and the more general more or less amounts to a combination of sequences-and-series and trigonometry.

2

For the record, there are 660 questions tagged trigonometric-series, 545 tagged with both sequences-and-series and trigonometry, 67 with these three tags. There are also 4155 questions tagged fourier-series, and 59 that are tagged with both fourier-series and trigonometric-series.

Martin Sleziak

SEDE returns only 67 cases when the tag (trigonometric-series) was removed: data.stackexchange.com/math/query/1038474/…

Martin Sleziak

2:02 PM

@ArnaudD. Back in 2016 there was this suggestions: Merging “fourier-series” and “trigonometric-series”?.

However, even if mods agreed to do this, a major clean-up would be needed first.

Comments from the old discussion:

I do not think this is a good idea; these are different topics. Both tags serve different purposes, and I would prefer keeping them separate. The theory of trigonometric series is a (very) classical topic, and as such not so active nowadays, which explains the smaller number of questions. (Personally, I am interested in some research problems that definitely belong to this area, and for which the techniques of Fourier series seem irrelevant.) — Andrés E. Caicedo Jun 13 '16 at 12:27

@AndrésCaicedo: The current description of "fourier-series" says: "Questions on Fourier series, the expansion of a function in terms of basis functions that satisfy an orthogonality relation. Usually, complex exponentials or sines and cosines are used." To me, this is not significantly different from the current description of "trigonometric-series" (notice that Fourier series explicitly mention sines and cosines as a possible basis). — Alex M. Jun 13 '16 at 12:34

@AndrésCaicedo: For abstract Fourier analysis there is the tag "harmonic-analysis". — Alex M. Jun 13 '16 at 12:35

Arnaud D.

2:20 PM

@MartinSleziak Thanks for the link. So apparently it may not be as similar to fourier-series as I thought. Then maybe the tag-excerpt could be edited to make the meaning of "trigonometric series" more explicit and discourage the more general usage I described above.

Martin Sleziak

I do not doubt that Andrés E. Caicedo's knows a lot about these things, but it seems that Alex M. disagrees with him.

I do not consider myself knowledgeable enough whether there is sufficient disticntion to keep them apart.

Trigonometric series

A trigonometric series is a series of the form: A 0 2 + ∑ n = 1 ∞ ( A n cos ⁡ n x + B...

Fourier series

In mathematics, a Fourier series () is a periodic function composed of harmonically related sinusoids, combined by a weighted summation. With appropriate weights, one cycle (or period) of the summation can be made to approximate an arbitrary function in that interval (or the entire function if it too is periodic). As such, the summation is a synthesis of another function. The discrete-time Fourier transform is an example of Fourier series. The process of deriving the weights that describe a given function is a form of Fourier analysis. For functions on unbounded intervals, the analysis and...

Probably, there is, but it would be good to hear from somebody who knows more about this.

In any case, the current usage of trigonometric-series seems to be a big mess - and far from the description given in the tag-info.

Arnaud D.

@MartinSleziak True, but Andrés' comment has been upvoted more than Alex's and has the same total score as the question... None of this is very conclusive, of course.

@MartinSleziak Agreed. Maybe the precise form defining a trigonometric series could be added in the excerpt, to say something like "For questions about or related to trigonometric series, i.e. series of the form $a_0 + \sum_{n = 1}^{\infty} (a_n \cos{nx} + b_n \sin{nx})$ or $\sum_n c_n e^{inx}$."

Martin Sleziak

2:36 PM

Yes, that sounds reasonable. I think you should go ahead and suggest the edit.

Arnaud D.

@MartinSleziak I just did it. I took the opportunity to correct (what I think was) a mistake in a formula in the tag-wiki.

Martin Sleziak

The excerpt edit has already been approved: math.stackexchange.com/posts/538949/revisions For the tag-wiki, I'll leave it to more knowledgeable users to see whether or not it was indeed a mistake: math.stackexchange.com/posts/538948/revisions

Martin Sleziak

3:56 PM

@MartinSleziak So that we can later check whether the numbers went down: At the moment, there are 125 questions tagged divergence-operator+sequences-and-series and 158 questions tagged divergence-operator+convergence-divergence.

Xander Henderson

4:33 PM

@MartinSleziak I will start making efforts to clean up the tag.

Martin Sleziak

5:12 PM

specific-question The tag gcd-and-lcm seems a good choice for $\gcd (a,b) = 1$ then $\gcd (a^n,b^k) = 1$ - however, all five slots for the tags are already taken.

I have removed (number-theory) and left only (elementary-number-theory) - perhaps that is reasonable.

Xander Henderson

6:12 PM

Tags seem, in general, to be better when they are words, rather than abbreviations. Would it be reasonable to create a new tag singular-value-decomposition, then make the existing tag svd an alias of that?

2

(or rename svd to singular-value-decomposition, then make the former an alias of the latter---whatever technical thingy needs to be done)

Martin Sleziak

In fact, suggestion along these lines have been made before:

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A: Expanding abbreviated tag names

I also went trough the list of extremely short tags (using this query). svd can be expanded into singular-value-decomposition lft can be expanded into linear-fractional-transformation sos can be expanded into sum-of-squares-method rbf can be expanded into radial-basis-functions pde can be expa...

Xander Henderson

@MartinSleziak Thanks!

Martin Sleziak

However, that post was about several tags.

My guess is that if you post the proposal to create a synonym in the tag management thread, it will quickly gains several upvotes.

And if you mention the above post in passing, perhaps mods will have a look also on other tag names suggested back then by wythagoras.

I see that you've mentioned this in the mods' office. So let's hope that somebody will respond.

Xander Henderson

6:29 PM

I was just about to mention that I had poked the mods.

You're too fast! :P

Feeds

10:29 PM

0

Q: $\rm\LaTeX$ Preview While Editing Tag Wikis from Chromium-Based Browsers

I've edited a few tag wikis, and I have found that the $\rm\LaTeX$ preview is quite spotty in Chromium-based browsers such as Chrome and Vivaldi. Most of the time, the equations in the tag wiki don't render at all. In Safari or Firefox they render just fine. This is not an issue with questions an...

bug mathjax tag-wikis

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$Mathematics$ Tagging