# User talk:YohanN7

Hi. Thank you for your recent edits. Wikipedia appreciates your help. We noticed though that when you edited Wigner's classification, you added links pointing to the disambiguation pages Spin and Helicity (check to confirm | fix with Dab solver). Such links are almost always unintended, since a disambiguation page is merely a list of "Did you mean..." article titles. Read the FAQ • Join us at the DPL WikiProject.

It's OK to remove this message. Also, to stop receiving these messages, follow these opt-out instructions. Thanks, DPL bot (talk) 10:48, 6 April 2017 (UTC)

## Spacetime Drive-by tagging

Only way to stop the "Son of Ref" tagger is to quickly add a bunch of references.

I've been working on them! No sweat. I think that I've located the primary sources for most of the later, poorly referenced sections. It seems to me that a bunch of guys who wanted to show off their "advanced" level of understanding looked up some graduate level texts and just added stuff randomly, not caring that most of the material that they added was totally irrelevant to the typical Wikipedia user.

Being a pack rat, I'm reluctant to section blank this stuff, despite its poor quality, until I've provided a good substitute.

I've been spending the last few weeks writing an Introduction section which I hope to be accessible to an intelligent high school student who is willing to put some effort into understanding the material. I've so far managed to limit myself to two (2) equations, preferring to substitute diagrams for math. The majority of the diagrams are mine, many newly created for this article.

Anyhow, leave the template alone. In a few weeks, I should have the article sufficiently referenced that I should be able to remove the tag and not be afraid of "Son of Ref" restoring it.

Thanks! Stigmatella aurantiaca (talk) 17:51, 13 April 2017 (UTC)

I've been enjoying myself with your article Representation theory of the Lorentz group. Not the whole article, just the prerequisites section. All of the material that you presented in this hidden section was thoroughly familiar to me once upon a time about 40 years ago, before I switched majors from physics to biology.
Anyhow, I've been considering adding a hidden Summary section to the Introduction section of the Spacetime article, sort of like your prerequisites section. What I am thinking about is something like this summary on the Spacetime "Talk" page. Unfortunately, the {{Hidden begin}} template doesn't work on mobile, and a non-hidden Summary section would be very detrimental to the user experience of somebody accessing the article on a phone.
Is there any precedent for creating an entirely separate Wikipedia article whose sole purpose is to be optionally wikilinked to?
If such a thing is allowed, then maybe I would title the article something like "Spacetime/Introduction Summary"? Then I could have something like this, which should work equally well on desktops and mobile:

### Summary

Spacetime/Introduction Summary

What do you think? Stigmatella aurantiaca (talk) 05:05, 18 April 2017 (UTC)
I'll get back later and respond with more detail. But as far as the tag goes, it is no longer there. The point (at least my point) is that every article needs more citations, but no article needs the tag. Especially not "popular" ones. It is obvious to everyone. At any rate, this article had about 30 citations when I removed the tag (and about 40 now). This is well above the average for a C-class article. YohanN7 (talk) 07:19, 19 April 2017 (UTC)
I sort of hope in the future to develop a second section covering the Lorentz transformation to introduce the math of spacetime. In doing so, I want to stay as far away from the two-postulates approach as I possibly can. I may or may not want to follow Taylor and Wheeler as a model. I envision the second section as being non-calculus-based and accessible to a high school senior. A third section will introduce weak fields, and I don't see how to avoid calculus. I do, however, think that it should be possible to make the material accessible to a high school AP or freshman college science student. Stigmatella aurantiaca (talk) 20:21, 19 April 2017 (UTC)

Stigmatella aurantiaca (talk) 22:59, 19 April 2017 (UTC)

## Your GA nomination of Representation theory of the Lorentz group

Hi there, I'm pleased to inform you that I've begun reviewing the article Representation theory of the Lorentz group you nominated for GA-status according to the criteria. This process may take up to 7 days. Feel free to contact me with any questions or comments you might have during this period. Message delivered by Legobot, on behalf of SparklingPessimist -- SparklingPessimist (talk) 18:01, 21 April 2017 (UTC)

## Your GA nomination of Representation theory of the Lorentz group

The article Representation theory of the Lorentz group you nominated as a good article has been placed on hold . The article is close to meeting the good article criteria, but there are some minor changes or clarifications needing to be addressed. If these are fixed within 7 days, the article will pass; otherwise it may fail. See Talk:Representation theory of the Lorentz group for things which need to be addressed. Message delivered by Legobot, on behalf of SparklingPessimist -- SparklingPessimist (talk) 16:20, 11 May 2017 (UTC)

## GAN

It is possible that my wording in the current GAN was not unambiguous. I did not mean to say you plagiarize a text-book, but that the exposition is like in a textbook (concerning of the level of detail).

Since you were digging your heels into the Good Article Criteria, I cannot refrain from applying these criteria, applied to the current version of the article.

1a:  Fail (not free of spelling errors, the prose is often both verbose and lacking precision)

1b:  Pass

2a-2d:  Pass

3a: I am not an expert, from what I can tell though:  Pass

4:  Pass

5:  Fail [under the current changes]

6a-6b:  Pass

7:  Fail

Good luck with the article. Jakob.scholbach (talk) 18:02, 18 May 2017 (UTC)

## Representation theory of the Lorentz group

Hi! Thank you for the work you have been doing on that page, I just wanted to make two suggestions:

1. Lets change the in-line Lie algebra notation. Doesn't ${\displaystyle {\mathfrak {sl}}(2,\mathbf {C} )}$ looks far better than sl(2, C) for example? If you agree let me know and I will make the changes.
2. The table in 3.3.2.2.1 needs to change. Why purple? Why bold?? One sees the diagonal there is no need to use boldface as a reminder! Also having the sums for ${\displaystyle m\neq n}$ in the same cell of the table as the ${\displaystyle (m,n)}$ representation strikes me as confusing. Let's have a table that only does ${\displaystyle (m,n)}$ pairs with an added row and column for ${\displaystyle {\tfrac {3}{2}}}$ and talk about the direct sums separately.

Latex-yow (talk) 20:01, 23 May 2017 (UTC)

Both excellent suggestions!
Some "history" about the inline notation: It used to be that PNG was default rendering, and inline Latex looked worse than awful, sometimes the size was double that of surrounding text and alignment was off. It was also the case that neither MathML nor MathJax could render all Latex in the article. Inline HTML math templates looks decent (but no more) on all devices. This has changed; now MathML is default, and some show-stopping bugs have been fixed.
Maybe the table could go up to 2? (Thinking gravitons here.) But this is not important, and would perhaps leave too many blank cells.
By the way, do you (or anyone) know which one corresponds to the adjoint representation? For the real (not complexified!) Lie algebra it is one of the irreducible ones since ${\displaystyle {\mathfrak {so}}(3,1)}$ is simple (has no non-trivial ideals). It is not ${\displaystyle (1,0)\oplus (0,1)}$ as has been suggested, though this works out for the complexified Lie algebra. Counting dimensions, it has to be one of ${\displaystyle ({\tfrac {5}{2}},0)}$, ${\displaystyle (1,{\tfrac {1}{2}})}$, ${\displaystyle ({\tfrac {1}{2}},1)}$, or ${\displaystyle (0,{\tfrac {5}{2}})}$, but with any of these, there are other problems (funny spin content) when one looks at the restrictions to ${\displaystyle {\mathfrak {so}}(3)}$ of the adjoint action. I am honestly confused about this. YohanN7 (talk) 07:43, 24 May 2017 (UTC)
And oh, this belongs better on the article talk page than here. YohanN7 (talk) 12:05, 24 May 2017 (UTC)
Yes we should copy some of this conversation on the talk page. At any rate I have started no. 1 and redid the table into a plain looking one with added row and column for 3/2. Will add 2 right after this. As for your question I don't know the answer but I will try to look it up.
Thanks. There was an error (now corrected) in my candidates for the adjoint representation. The list is built by counting the dimension (2m + 1)(2n + 1)) of the candidates, which must be 6, the dimension of the Lie algebra itself. YohanN7 (talk) 07:07, 26 May 2017 (UTC)