# User talk:Rgdboer

To facilitate current discussion an archive has been established to clear this page for 2017.Rgdboer (talk) 02:40, 22 December 2016 (UTC)

## Undoing edits

Hey, there!

I see that you undid all of my edits from last night on Protein combining without entering any information as to why. Please refrain from doing that. Let me know if you have any questions.

Thanks!

--SaletteAndrews (talk) 20:47, 13 January 2017 (UTC)

## Laurence Clancy

Hello Rgdboer. I was delighted to see you started a new article on Laurence Joseph Clancy! I started an article on the same person in about 2008 but after a few months it was listed for deletion and, despite my best efforts, the listing was successful. You can read the deletion debate at Wikipedia:Articles for deletion/Laurence Clancy. This will show the sort of argument people brought to bear to have "my article" deleted in 2008, and the sort of argument we need to be able to combat in 2017.

You may wish to ask an Admin to retrieve my 2008 article in order to see what it said, and what citations were supplied. Either way, I am happy to contribute to your new article to make it as robust as possible so it can withstand any future deletion debate.

I continue to cite Clancy in most of the aerodynamics articles I work on, so I am very glad Wikipedia again has some information about him. Best wishes, Dolphin (t) 03:42, 16 January 2017 (UTC)

PS: I have asked an Admin to send me the text of my 2008 article; see my diff. Let me know if you want a copy. Dolphin (t) 02:41, 18 January 2017 (UTC)

PPS: User:RHaworth has restored the 2008 edits to the history of Laurence Joseph Clancy. Earlier versions can be seen by selecting them in the history of the current article. Dolphin (t) 04:04, 19 January 2017 (UTC)

## I was going to be eliminating those subheader titles that you changed, but thanks!

The way that the section in Spacetime was going, I was going to delete the subheaders, but thanks! I've always appreciated your contributions! Stigmatella aurantiaca (talk) 23:13, 24 March 2017 (UTC)

## Liebmann (1905)

You wrote in Möbius_transformation#Lorentz_transformation, that Liebmann (1905) noted the isomorphism between Lorentz group and Möbius group. However, the 1905 edition of his "Nichteuklidische Geometrie" does not contain (as far as I can see) any discussion of the Lorentz group (in the 1923 edition there is a little bit). I think a better source is Herglotz (1909), who pointed out that "Lorentz transformations definitely correspond to hyperbolic motions in ${\displaystyle R_{3}}$", transforming the unit sphere into itself (p. 407). Using Klein's classification of hyperbolic motions, Herglotz separated the one-parameter Lorentz transformations into loxodromic group, hyperbolic group, elliptic group, and parabolic group (p. 408). --D.H (talk) 11:30, 28 June 2017 (UTC)

Thank you for the notes and links on this fascinating topic. Given that special relativity is a branch of linear algebra (with physical content), the alignment of the Riemann sphere with the celestial sphere accomplishes the Möbius-Lorentz group correspondence. Liebmann was cited because Coxeter mentioned him, but now it seems Herglotz is more appropriate. These century-old sources show that Penrose was a late-comer to this topic. — Rgdboer (talk) 23:22, 28 June 2017 (UTC)

I've now included a description of the formulas of Fricke & Klein (1897) and Herglotz (1909) in Spherical_wave_transformation#Conformal_group_isomorphic_to_Lorentz_group. Regarding Liebmann (1905), on pp. 52ff. he discussed the relation between hyperbolic motions and "Kreisverwandtschaften" (Möbius transformations), obtaining and extending some results of Fricke & Klein (without citing them). In the third edition of his book from 1923 (on p. 143), Liebmann mentioned the relationship between Lorentz transformations and motions of the hyperbolic plane using Weierstrass coordinates. --D.H (talk) 11:59, 20 July 2017 (UTC)

The following relevant reference has flaws:
• Remi Langevin (2015) Integral Geometry from Buffon to Geometers of Today, chapter 18 "Integral geometry of Lorentz spaces", page 147, Société mathématique de France ISBN 978-2-85629-822-0
The misprint in the description of Pz (third line from bottom of page) has ${\displaystyle {\mathcal {L}}(x,z)=1}$ where it should be ${\displaystyle {\mathcal {L}}(x,z)=0.}$ This orthogonality property is given at the outset, but omits to mention hyperbolic orthogonality as the non-perpendicular meaning in this case. The use of Möbius name is overly broad, being invoked for SO(1,1) and the term Mob used instead of Lorentz group as is standard. Langevin's effort to sketch the Mobius-Lorentz group isomorphism is a gloss, not a proof. Rgdboer (talk) 01:37, 25 December 2017 (UTC) — Rgdboer (talk) 01:46, 25 December 2017 (UTC)

You may be interested in

as well as in the recent additions to

with a bunch of many other authors having historical variants of Lorentz transformations via Weierstrass coordinates, or via Cayley absolute, or via Cayley-Hermite transformation, or via Quaternions etc. (PS: Liebmann did indeed have the Lorentz transformations in 1905, which I initially overlooked). --D.H (talk) 21:44, 22 March 2018 (UTC)

## Unblock

Requested text:

This user's request to have autoblock on his/her IP address lifted has been reviewed by an administrator, who accepted the request.
Rgdboer

Block message:

Autoblocked because your IP address was recently used by "Theskyisblue". The reason given for Theskyisblue's block is: "Abusing multiple accounts: Please see: [[Wikipedia:Sockpuppet investigatio...

Accept reason:

It looks like collateral damage. I've unblocked you. Let me know if you have further trouble. NinjaRobotPirate (talk) 03:33, 1 October 2017 (UTC)

Thank you. — Rgdboer (talk) 02:42, 1 October 2017 (UTC)

## ArbCom 2017 election voter message

 Hello, Rgdboer. Voting in the 2017 Arbitration Committee elections is now open until 23.59 on Sunday, 10 December. All users who registered an account before Saturday, 28 October 2017, made at least 150 mainspace edits before Wednesday, 1 November 2017 and are not currently blocked are eligible to vote. Users with alternate accounts may only vote once. The Arbitration Committee is the panel of editors responsible for conducting the Wikipedia arbitration process. It has the authority to impose binding solutions to disputes between editors, primarily for serious conduct disputes the community has been unable to resolve. This includes the authority to impose site bans, topic bans, editing restrictions, and other measures needed to maintain our editing environment. The arbitration policy describes the Committee's roles and responsibilities in greater detail. If you wish to participate in the 2017 election, please review the candidates and submit your choices on the voting page. MediaWiki message delivery (talk) 18:42, 3 December 2017 (UTC)

## History of logarithms

R, this version you wrote has a story similar to the one we just fixed at Napierian logarithm. The ref 13 doesn't appear to support what's said about this. Care to weight in on where to take this? Dicklyon (talk) 02:33, 13 May 2018 (UTC)

Please correct. That text was copied from Logarithm when History of logarithms was begun. November 24, 2015, the Logarithm article was seen to be too long, with much historic material. The namespace "History of logarithm" had a redirect to Logarithm, so text was moved to reduce Logarithm and begin an independent article. The prehistory of natural logarithm includes the story of Napier, but my efforts have been expended on A. A. de Sarasa and Gregoire de Saint-Vincent. While mathematics resists the notion of paradigm shifts, the invention of logarithms was revolutionary for productivity and setting up calculus. — Rgdboer (talk) 21:27, 14 May 2018 (UTC)

## Relational view on functions

I just came here to express my wish/hope that you do not bother my use of your idea for these edits. Besides your unlucky use of a (typoed?) link, I shared D.Lazard's view of the original place not really being an optimal one. I expect that the new place and the reduced content might find grace in the eyes of the lords. It is beyond me to invite you to possibly add contents, according to your ideas (composition as another example?), but at least I want to say thanks for the trigger. Purgy (talk) 11:04, 7 September 2018 (UTC)

You’re welcome Purgy! Thank you for moving the material higher up the article. Editing on an frequently-viewed article is adventurous! But of course, relation is prior to function. — Rgdboer (talk) 02:19, 8 September 2018 (UTC)

## Kutta condition

Hi Rgdboer. We are under siege at Talk:Kutta condition#"An aircraft with a wing with a smoothly rounded trailing edge would generate little or no lift.". If you are able to comment that would be appreciated. Regards. Dolphin (t) 13:21, 7 October 2018 (UTC)

A figure from flow separation was used to comment on lift (force) and use of potential flow. — Rgdboer (talk) 02:14, 9 October 2018 (UTC)
Many thanks for your contribution. I have commented on the Talk page.
I’m sure you are aware that potential flow is based on the assumption of zero viscosity, whereas flow separation occurs because of viscosity, so I find mention of both in the same sentence to be challenging. Dolphin (t) 12:25, 9 October 2018 (UTC)