User talk:Rgdboer

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Hello Rgdboer and welcome to Wikipedia! Hope you like it here, and stick around.

Here are some tips to help you get started:

Good luck!

Hi. Welcome to Wikibooks from me also. Style tips: you don't need to add spaces to the start of every line. Just type normally and let the text wrap around. Please italicise variables also. You might be interested in Wikipedia:Wikiproject Mathematics. Dysprosia 02:08, 7 Nov 2004 (UTC)


Leaf vegetables[edit]

There is now an article leaf vegetable, which you might find convenient for the self description on your user page.

Regards — Pekinensis 00:56, 19 Mar 2005 (UTC)

Whole grain[edit]

There is now an article whole grain, which you might find convenient for the self description on your user page.

Regards — Pekinensis 22:40, 15 Jun 2005 (UTC)

Tessarines, hypercomplex number[edit]

Dear Rgdboer,

I've added some isomorphic algebras to the article on tessarines which you may find interesting. In my eyes, tessarines with complex number coefficients actually form a mathematical field (not just a ring), since they are commutative, associative, and contain a multiplicative inverse for any non-0 element. If you agree, we could change this.

I'm currently asking around for opinions, also because of some concerns I have added to the discussion page of the hypercomplex number article. I'm currently soliciting comment from various parties, including you (since you've written much about non-traditional numbers in Wikipedia). Any feedback is appreciated; if you are in disagreement, or have a different suggestion, please respond on the discussion page of hypercomplex number to simplify the discussion.

Thanks, Jens Koeplinger 15:06, 19 July 2006 (UTC)

Thanks for letting me know that tessarines contain numbers with determinant t = zz - ww = 0, and are therefore not a field. Thanks, Jens Koeplinger 13:39, 20 July 2006 (UTC)
Hello. I've replaced the hypercomplex number article with a complete rewrite, which should include all previous content and statements, but with much more detail and categorization. I'm referring to many pages you've been editing here, and would appreciate any feedback. Thanks, Jens Koeplinger 22:36, 31 July 2006 (UTC)


(I’m not creating a new section because the current one is closely related to my question.)

Some time ago, in the “hypercomplex number” article, you have removed without explanation nor reference the sentence saying that:

None of these extensions other than the real or complex numbers form a field, because the field of complex numbers is algebraically closed by the fundamental theorem of algebra.

Would you have some example of an hypercomplex extension being a field and thus justifying that removal?

Thanks. — Ethaniel (talk) 11:47, 16 February 2016 (UTC)

Yes, in 2010 that trim was made since it cut too closely the broad topic opened in the article. The fact that most hypercomplex number systems are not fields is virtually non-descriptive, and holds up a standard inappropriate for most instances. However, since these algebras are vector spaces, the field concept is at the heart of hypercomplex number theory. — Rgdboer (talk) 01:29, 17 February 2016 (UTC)
As I’m not a native English speaker I’m not sure to have fully understand your answer: Do you mean that the sentence was right (i.e. that the only hypercomplex algebras actually being fields are indeed ℝ and ℂ) but that it may lead the reader to believe that only field-like hypercomplex algebras would be interesting to study because it was in the article introduction instead of a simple note, hence your removal?
My main concern is the rightness of the sentence more than its utility or its effect on the reader, as the French article is based on a 2006 version of the English one, and is thus including the sentence you have deleted: Should I delete the French sentence because it is plain wrong or could I leave it (possibly with a comment about its non-descriptiveness) because it is nevertheless right?
Thanks. — Ethaniel (talk) 14:00, 18 February 2016 (UTC)
Thank you for your interest in the French language approach to hypercomplex numbers. I would suggest reviewing the work of Jules Houel as he carried forward the study in that language, but not too well. To get some context, visit history of quaternions and Quaternion Society. As for the sentence, it is not wrong so it could be left. French literature includes The Theory of Spinors (1938) by Elie Cartan which was negligent in crediting previous expositions of the material in English, and generally the hypercomplex systems developed in English have not been recounted by Continental mathematicians. — Rgdboer (talk) 03:22, 19 February 2016 (UTC)

Thanks again - coquaternion, hyperbolic quaternion, etc[edit]

Rgdboer, thanks again for your help, clarifications, and clean-up that led to good improvements to several number system articles. When I started adding isomorphisms, I first noticed one here, then another there, and over the past two months there turned-out to be a flood of isomorphisms, many of which I've for now put on hold with adding. Maybe some time later we may want to think about creating a section on each of the number systems that are currently being referenced from hypercomplex number, and title it "Isomorphisms"? We could place such a section at the same position at each article, e.g. before or after the "See also" section, or maybe even as a subsection to the "See also"?

From my end, I'll slow down for a few months, to see what comes out from the Musean hypernumber debate. I had contacted authors of two more hypercomplex extension programs, which are currently not listed in Wikipedia at all, but after seeing what happend to the authors of the material which I refered to for the Musean hypernumber article, I better not dare to ask anyone whether they still want me to write-up a Wiki article about their numbers :) ... For good reason, of course. On the other side, I'm not comfortable in representing works from certain sources in a way that differs conceptually from these sources - which seems to be what some may have requested for the Musean hypernumber article ... also for good reason.

Anyway, let me know if there's anything urgent that you'd like to see done in Wiki (errors; bad, incorrect, or misleading statements - anything that really shouldn't be here).

Thanks again, Jens Koeplinger 00:43, 23 August 2006 (UTC)

The "complex plane"[edit]

Hello, Rgdboer!

I'm responding to a remark you put on the talk page for this article.

I have recently added a substantial amount of new material to this article, and I included a small section (Other meanings of "complex plane") near the end. I hope I've addressed most of your concerns. Since you seem to be a lot keener on abstract algebra than I am (although I did take a course on group theory from a guy named Aschbacher a long time ago), I'd appreciate your assistance with one little thing.

I'd like to add one or two more paragraphs explaining why the (Eulerian/Gaussian) complex numbers have generated so much interest in analysis, while the other 2-dimensional algebraic extensions of the reals (split-complex, dual numbers) have not generated such a vast literature. I suppose it's mainly because you can't get a positive definite norm on the split-complex / dual numbers. That, and the fundamental theorem of algebra. Anyway, I'd appreciate hearing more about your views before I write those one or two additional paragraphs. Or maybe you'd like to stick something in there.

Oh -- on the "complex plane" as C×C, I'm thinking that some allusion to Cantor's mapping of C into R might be fun to put in there. What do you think?

Have a great day!  ;^> DavidCBryant 23:56, 6 January 2007 (UTC)

Thanks for expanding Isaak Yaglom[edit]

Thanks for expanding Isaak Yaglom and for adding the annotated list of works. What was your source for the biographical details you added? --Jtir 15:48, 10 June 2007 (UTC)

All the biographical information I used is from the Russian Mathematical Surveys v.44 obituary listed in the references. Rgdboer 22:27, 11 June 2007 (UTC)
Thanks. I have added <ref> tags citing it. I added an introductory sentence to the Institutes and titles section to have a place to hang the <ref> tag there. --Jtir 22:07, 12 June 2007 (UTC)

Your extraordinary degree of detail, precision, and insistence of historical facts[edit]

Robert - during the past year or so I've come across several of your edits in certain algebra related articles, most recently in the discussion about merging split-/para-/hyperbolic-/coquaternions into one article. During every edit you have exhibited an extraordinary desire to present and preserve historically and factually correct information. It is your diligence that actively provides better and more profound support of factual and historical information in Wikipedia. Therefore you truly deserve:

Barnstar of Diligence.png The Barnstar of Diligence
For your active contribution and clarification of historical facts in 19th century algebra related articles. Jens Koeplinger 01:06, 11 June 2007 (UTC)

Thank you.Rgdboer


Hello Rgdboer, I am very interested in your work about inversive rings and conformal geometry. So I wish to know how I could adquire more information about your work, maybe books or papers... I am a spanish researcher and my email is XXXXXXXXXXXX. Thanks you very much —Preceding unsigned comment added by (talk) 11:48, 7 September 2007 (UTC)

Please do not leave your e-mail address here, for your own sake, as this is a public place. Generally the "User talk" is for Wikipedia business: pages in development, work done or to be done, progress reports. If you have a need to contact me personally for any reason, click on the "E-mail this user" in the left column toolbox. I will reply and we can carry on our research or what have you.Rgdboer 22:37, 13 September 2007 (UTC)


This "User talk" space is for whatever comments or concerns may arise from readers at large or WP editors. Just click on the "edit" to the upper-right, and when the "Editing" window opens begin typing at the left margin.Rgdboer (talk) 20:56, 12 February 2008 (UTC)

Thoughts on Vector (Gibbs-Heaviside)[now deleted][edit]

I noticed your work on Vector Analysis (Gibbs/Wilson). I'm wondering if an editor of a related-article would have some thoughts on the Vector (Gibbs-Heaviside) article. Very happy to learn first hand your thoughts on it or those of current and possible future wikipedia articles on vector analysis. --Firefly322 (talk) 11:09, 8 March 2008 (UTC)

You have my recent remarks at Talk:Vector (spatial)#Historical remarks. Beyond that let me keep researching, reading, studying, and thinking.Rgdboer (talk) 00:07, 12 March 2008 (UTC)

Walter Bradford Cannon[edit]

Hi I am from the country of your Grand Parents. You just made added a "high school mentor" to the Walter Bradford Cannon. Could you tell me your source, because I couldn't find this on Google. -- Marcel Douwe Dekker (talk) 22:12, 17 June 2008 (UTC)

Hi Mdd: Saul Benison (1987), WBC: Life and Times a Young Scientist. I'll get the page number soon. Have added this book and a 2000 sequel to the references. I would also like to eventually work in his relationship with G. W. Pierce. The formation of these individuals interests me greatly.Rgdboer (talk) 22:20, 17 June 2008 (UTC)
Thanks. I think you should add this source to the article itselve with a reference-tag. I wikified your other contributions myself. Good luck. -- Marcel Douwe Dekker (talk) 22:31, 17 June 2008 (UTC)

Economic crisis of 2008[edit]

Hi, I just wanted to let you know I reverted your edit to Economic crisis of 2008 as it sounded too much like wp:or. If you have some sources for this, please feel free to reinsert the information. NJGW (talk) 00:33, 12 July 2008 (UTC)

References on Age wave so no OR. Difficult to blame constrictive population pyramid cause for stagnation.Rgdboer (talk) 21:25, 12 July 2008 (UTC)

Nine-point hyperbola[edit]

Hello. I just added nine-point hyperbola to the list of triangle topics. If you know of others that should be there and are not, could you add those too? Thanks. Michael Hardy (talk) 20:26, 13 July 2008 (UTC)

Graphics lab[edit]

I've replied to your request at the graphics lab here. --pbroks13talk? 22:37, 13 July 2008 (UTC)

Pappus harmonic theorem[edit]

I've replied to your query at Talk:Projective_harmonic_conjugates Dickdock (talk) 21:34, 6 September 2008 (UTC)

AfD nomination of Tessarine[edit]

Ambox warning pn.svg

I have nominated Tessarine, an article you created, for deletion. I do not think that this article satisfies Wikipedia's criteria for inclusion, and have explained why at Wikipedia:Articles for deletion/Tessarine. Your opinions on the matter are welcome at that same discussion page; also, you are welcome to edit the article to address these concerns. Thank you for your time. Ben (talk) 08:12, 11 September 2008 (UTC)


Hi, could you please look at that page: Talk:History of special relativity#Tessarines?. It's about the inclusion of the section "Mathematical Background" in the article and the importance for the history of special relativity. --D.H (talk) 21:16, 28 October 2008 (UTC)

Routh's theorem[edit]

You added the following text to the article on Routh's theorem:

This theorem was given by Edward John Routh on page 82 of his Treatise on Analytical Statics with Numerous Examples in 1896. The particular case has become popularized as the one-seventh area triangle.

I checked page 82 (and several other pages) of that Treatise (which most people date to 1898 instead of 1896), but could not see any mention of this result. Could you double-check that reference? —Preceding unsigned comment added by (talk) 21:08, 2 November 2008 (UTC)

Oh, never mind... I found it in a different edition of that Treatise. (The page numbers must have changed.) Thanks. —Preceding unsigned comment added by (talk) 02:17, 3 November 2008 (UTC)

Alexander Macfarlane (mathematician)[edit]

Hi, I'd be glad to help, but I'm bit busy this week with finals and papers and all. Leave me a message with how/where I can access this letter and I will do what I can to find the information to you (assuming that I can access it of course!) next weekend or so. Cheers, CP 19:14, 30 November 2008 (UTC)

Thank you Canadian Paul for chasing down that letter from Helen Macfarlane in the archives at your university.Rgdboer (talk) 02:10, 8 January 2009 (UTC)

Screw theory[edit]

Hi Rgdboer - happy new year! A few month ago, you asked me a question regarding the calculus of screws. I just got an email that there will be a summer school for screw theory based methods in robotics (here), and I thought you might be interested in taking a look. --Jiuguang (talk) 16:23, 13 January 2009 (UTC)

My interest in screw algebra stems from efforts to improve the articles on Eduard Study and his biquaternions. I learned of a line of work by Yang, McCarthy, Rooney, and Baker; see dual quaternion#References. Some of the math puzzled me so I started asking around, including User talk: Jiuguang Wang. Good to see math for robotics etc., but some claims seem dubious.Rgdboer (talk) 01:28, 1 February 2009 (UTC)
After reading Julian Coolidge on screw theory in his A History of Geometrical Methods (1940) in October 2013 the method of screw displacement by homography became apparent. This topic has been perpetuated in engineering schools for decades; it deserves to be assimilated into mainstream modelling of motion. However, Chasles' theorem (kinematics) is a key result that we need yet to provide with an elementary proof.Rgdboer (talk) 23:21, 19 June 2014 (UTC)


Your edits on the Charles Proteus Steinmetz were very interesting as to information, and it fits pretty well with what I know about him also... but could you find outside references say to the book or a book about the book to make a ref/citation note to the information? If there is a copy of the book you mention on line or a description of the passages that would work well I think or a book about the book. If you have something like that and do not have the time to connect it together I could probably do it also if you could give me a link to further info. Best wishes to you. skip sievert (talk) 23:00, 30 May 2009 (UTC)

The latest biography of Steinmetz is Ronald Kline (1998). Reading that biography in connection with his applied complex variable work, brought me to his essay on "political economy" which anticipated a convergence between corporations of industrial and social type. Due to the current events that show Steinmetz had some insight 93 years ago, I read through the book, selected a couple key quotes, and contributed the now deleted addition to his biographical article.Rgdboer (talk) 22:10, 31 May 2009 (UTC)
I was able to find this,, as to the book you are referring to... Despite his efforts, by 1922 Steinmetz concluded that socialism would never work in America because the country lacked a "powerful, centralized government of competent men, remaining continuously in office" and because "only a small percentage of Americans accept this viewpoint today. That was written by Kline.. here is a link [1] - I am a fan also of Steinmetz as you are. He was a notable genius very obviously. You may find it interesting to investigate his involvement at Columbia University in the Technical Alliance. My guess is that he modified his view very significantly between when that book was written and his death. The concept of [2] was the focus of his last few years I think. This revolves around something connected with this [3] in an Energy accounting system using Thermoeconomics in a non monetary system... so that pretty much eliminates corporations as are known in that sense. That does not take away from his book at all published before his contact with that group and it would be good to add some of the info... and put it all into context in the article. Here is another link you may find interesting [4] If this information is not interesting to you please just ignore it. Regards, skip sievert (talk) 22:58, 31 May 2009 (UTC)

Space time[edit]

Concerning your mathematical model of space time, How about developing a 4 dimensional spacetime model by investigating the mathematical relationship of the diagonal of a cube to the 3 side diagonals. Then we could hypothetically carry out a 3 dimensional Michelson-Morley experiment with light originating at the beginning of the diagonal, and with the time vector congruent with the diagonal. Then the point of convergence of the returning light would be at the 2/3 point on the diagonal. And I assume there would still be no indication of "ether drag" in such a test. But I cant work out the mathematics of the effect of translation motion of the cube on the results of the experiment, and I wonder if you could help.WFPM (talk) 17:04, 10 August 2009 (UTC)

Thanks for your reply and please see my further discussion re this matter in my talk page.WFPM (talk) 15:01, 12 August 2009 (UTC)

Topology of pseudo-Riemannian manifold[edit]

I've put a comment on the talk page explaining (at least in the Minkowski spacetime) how to reconstruct the underlying topology from the pseudo-metric. I hope this is useful. (talk) 20:17, 19 August 2009 (UTC)

See Talk:Pseudo-Riemannian manifold#Oxymoron for the dialogue (some comments from an unnamed contributor have been moved there).Rgdboer (talk) 21:31, 4 September 2009 (UTC)

Cockle and Macfarlane WebCited[edit]

Hi, we crossed paths at History of special relativity, which led to my archiving the GeoCities pages on Cockle and Macfarlane. The Cockle links are on his page, here Macfarlane's:

Regards, Paradoctor (talk) 09:20, 26 October 2009 (UTC)

Synthetic spacetime in History of special relativity[edit]

You might be interested in this talk page item. Regards, Paradoctor (talk) 17:39, 26 October 2009 (UTC)

Articles for deletion nomination of Tachyboloid[edit]

Ambox warning pn.svg

I have nominated Tachyboloid, an article that you created, for deletion. I do not think that this article satisfies Wikipedia's criteria for inclusion, and have explained why at Wikipedia:Articles for deletion/Tachyboloid. Your opinions on the matter are welcome at that same discussion page; also, you are welcome to edit the article to address these concerns. Thank you for your time.

Please contact me if you're unsure why you received this message. TimothyRias (talk) 08:57, 18 November 2009 (UTC)

Read and remember:WP:NEO#Articles wrongly titled as neologisms. The phrase "it can be tempting to employ ... a neologism" says it all. Upon reflection, this policy maintains the authoritivity of WP. My mistake. A move to rapidity space conforms with the policy of a "descriptive phrase" title. The old title is now a redirect, soon to be deleted.Rgdboer (talk) 23:06, 22 November 2009 (UTC)
Readers interested can find some information at rapidity#In more than one spatial dimension. Fixing the name did not work.Rgdboer (talk) 02:06, 2 December 2009 (UTC)

Martin Gardner, James Randi, and the 1/7-area triangle[edit]

In the Martin Gardner article, there is a paragraph (which you added back in 2008) mentioning that Gardner told Randi about Steinhaus's geometrical "tiling" proof that the triangle has area 1/7. I don't understand what makes this more notable than any of the (probably hundreds of) other occasions when Gardner told some other fairly well known person about a nice bit of mathematics. (I also don't understand why it's included under the heading "Pseudoscience", since its only connection with pseudoscience is that the two people involved happen to be anti-pseudoscientists.) What am I missing here? [Note: I asked the same question on the talk page of that article, which might actually be a better place for further discussion, if there is any.] Gareth McCaughan (talk) 17:51, 30 December 2009 (UTC)

Articles for deletion nomination of Hyperbolic coordinates[edit]

Ambox warning pn.svg

I have nominated Hyperbolic coordinates, an article that you created, for deletion. I do not think that this article satisfies Wikipedia's criteria for inclusion, and have explained why at Wikipedia:Articles for deletion/Hyperbolic coordinates. Your opinions on the matter are welcome at that same discussion page; also, you are welcome to edit the article to address these concerns. Thank you for your time.

Please contact me if you're unsure why you received this message. RDBury (talk) 01:38, 5 June 2010 (UTC)

I have marked you as a reviewer[edit]

I have added the "reviewers" property to your user account. This property is related to the Pending changes system that is currently being tried. This system loosens page protection by allowing anonymous users to make "pending" changes which don't become "live" until they're "reviewed". However, logged-in users always see the very latest version of each page with no delay. A good explanation of the system is given in this image. The system is only being used for pages that would otherwise be protected from editing.

If there are "pending" (unreviewed) edits for a page, they will be apparent in a page's history screen; you do not have to go looking for them. There is, however, a list of all articles with changes awaiting review at Special:OldReviewedPages. Because there are so few pages in the trial so far, the latter list is almost always empty. The list of all pages in the pending review system is at Special:StablePages.

To use the system, you can simply edit the page as you normally would, but you should also mark the latest revision as "reviewed" if you have looked at it to ensure it isn't problematic. Edits should generally be accepted if you wouldn't undo them in normal editing: they don't have obvious vandalism, personal attacks, etc. If an edit is problematic, you can fix it by editing or undoing it, just like normal. You are permitted to mark your own changes as reviewed.

The "reviewers" property does not obligate you to do any additional work, and if you like you can simply ignore it. The expectation is that many users will have this property, so that they can review pending revisions in the course of normal editing. However, if you explicitly want to decline the "reviewer" property, you may ask any administrator to remove it for you at any time. — Carl (CBM · talk) 12:33, 18 June 2010 (UTC) — Carl (CBM · talk) 13:04, 18 June 2010 (UTC)

The Principles of Mathematics[edit]

Hi, Rgdboer! I just wanted to say how much I appreciate your recent work to improve this article. It's been a real pleasure to watch it develop with your additions. Thanks!  – OhioStandard (talk) 02:48, 3 October 2010 (UTC)

Vancouver Wikipedia 10th Anniversary Meetup[edit]

A small group of us editors gathered at the above location to mark the transition from the first to the second decade of the encyclopedia project. We enjoyed eachothers conversation as we chatted about the wikis. I did not stay to the end. The T-shirt I took home has the project name in many languages across the back, and the puzzle-globe logo on the front. Quite handsome!Rgdboer (talk) 01:42, 28 January 2011 (UTC)

Seeking your mathematical expertise[edit]

Hi, I'm looking over Pentagram map and am wondering -- is this stuff generally right? I never got much beyond calculus and statistics so I can't tell if this article is real. There's only one chief contributor to this article, although he seems thoroughly legit (Brown U. math prof) but he has been known to play pranks on fellow professors at Brown, and I'm wondering if you might have a look over the article and see if you think it's okay. --Tomwsulcer (talk) 23:23, 27 June 2011 (UTC)

It is an interesting article based on a simple geometric idea for a convex polygon. The active contributor did not start the article; it had other editors early on, but now the contributor has expanded it using himself and others as references. From what I know, no falsehoods are perpetrated though many of the references are beyond me. The section on cross-ratio is not yet referenced, but it seems the article is still evolving. The editor already has a barnstar posted to his Talk for his efforts. From the editor's use of his refereed articles it seems unlikely that a prank in afoot, unless those vehicles too are misled. Another reader will have to find a glich; perhaps more reading and thinking will show something, but so far it seems to be geometry. One may have reservations about the liberty with projectivity, since the finite plane does not cover the projective one. But a fault based on this observation ought to show up in one of the arguments.Rgdboer (talk) 03:07, 28 June 2011 (UTC)
Reassuring. Thanks so much. I have no idea what this stuff is about. I expanded the article Richard Schwartz nevertheless. When I came across evidence of the prank, and that the contributor was editing his own article, I raised an eyebrow, but with your paragraph above, it's been lowered with a smile.--Tomwsulcer (talk) 03:31, 28 June 2011 (UTC)

Revisions to article on Screw Theory[edit]

I have been working to revise the article on screw theory and because you made contributions over the years I thought it would be a good idea to let you know. What started as small changes are slowly growing in scale. I hope you find the additions to be useful. Prof McCarthy (talk) 05:52, 29 June 2011 (UTC)

See comments at Talk:Screw theory.Rgdboer (talk) 23:30, 29 June 2011 (UTC)


Hi Rgdboer, belated congratulations for contributing over 50 articles, I've now made your account an Autopatroller. Thanks for giving me some interesting reading. ϢereSpielChequers 21:34, 15 May 2012 (UTC)


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Hello, Rgdboer. You have new messages at Maschen's talk page.
You can remove this notice at any time by removing the {{Talkback}} or {{Tb}} template.

Thanks, Maschen (talk) 21:33, 30 November 2012 (UTC)

Please proofread the wikilinks to Rendiconti del Circolo matematico di Palermo that you've added lately[edit]

Either spelling of redirect needs to be exact, or use a piped wikilink.

Rendiconti del Circolo matematico di Palermo (capitalization incorrect in red wikilink)
Rendiconti del Circolo matematico di Palermo (piped wikilink)
Rendiconti del Circolo Matematico di Palermo (exact capitalization to redirect)
Stigmatella aurantiaca (talk) 01:38, 6 December 2012 (UTC)
For some inexplicable reason this User thought redlinks had been made. Evidently the User thought better when a change was made to the title of this section. Yes, always use Preview before Save to confirm edits.Rgdboer (talk) 21:01, 7 December 2012 (UTC)
I corrected a redlink that you added to Kaufmann–Bucherer–Neumann experiments by using a pipe. Checking your Dec 6 contributions show redlinks in Speed of gravity and Refractive index (both capitalization errors), while the reference that you added to Compact space showed blue. So Dec 6 was a bad day for you, 3 out of 4 being incorrect.
I've just reviewed your 13 references to Rendiconti del Circolo Matematico di Palermo made on Dec 5 and they are all blue.
Please correct your two remaining red Dec 6 contributions. And yes, please follow your own advice, and always use Preview. Stigmatella aurantiaca (talk) 01:14, 8 December 2012 (UTC)
Ok, Speed of Gravity and Refractive index done.Rgdboer (talk) 01:29, 8 December 2012 (UTC)
Bad days happen to the best of us. :-) Stigmatella aurantiaca (talk) 01:55, 8 December 2012 (UTC)

inversive ring geometry[edit]

Hello Rgdboer. I was recently looking at inversive ring geometry, but I was unable to find the topic elsewhere. Do you happen to have some reliable secondary sources on hand that support the contents and the name? I will watch this page for your response. Thanks! Rschwieb (talk) 21:07, 14 December 2012 (UTC)

There are seven references given. Walter Benz (1973) Vorlesungen uber Geometrie der Algebren develops the general theory of commutative rings. The non-commutative formulation encompasses a bit more. As stated, it just extends the usual projective complex line, or Riemann sphere, linear automorphisms (Mobius maps) to ring theory. Benz shows that there is a theory here, though constrained to the commutative case. Other references exhibit practitioners.Rgdboer (talk) 00:37, 15 December 2012 (UTC)
Before I continue again, let me say that the reason I am looking into this is that I was trying to find the topic "inversive ring geometry" on the web, and I had no luck. It's a crude litmus test on the notability of topics, you see.
Part of the difficulty here is that it is hard for me to verify that Benz's work contains this topic as a secondary resource. Do any of the texts refer to "inversive ring geometry" by name? Does the name appear anywhere else?
I have no doubt these ideas appear somewhere. What I am trying to discern is if there really is (as far as an encyclopedia would be concerned) a topic with this name.
Thanks! Rschwieb (talk) 11:56, 15 December 2012 (UTC)
The title blends inversive geometry with ring (mathematics) or ring theory. As the policy WP:Article titles states:
The ideal article title resembles titles for similar articles, precisely identities the subject, and is short, natural and recognizable.
The title W. Benz uses is Ketten, meaning Chains. In this project we have seven mathematical uses of this term, none appropriate: Chain (disambiguation)#Mathematics. Adopting some variant of that seems less than ideal.Rgdboer (talk) 00:26, 16 December 2012 (UTC)

So, in other words, the title is not actually used in any reliable secondary sources? Which of the secondary sources actually supports the point that this is really a self-contained theory? Rschwieb (talk) 02:58, 16 December 2012 (UTC)

The historical notes indicate the persistent urge of mathematical authors to form linear fractional transformations with elements from a ring, notably Study, Vahlen, and Cartan. But a line had to be drawn against non-associative rings such as hyperbolic quaternions since without associativity the relation defining points on the projective line is not transitive, and hence falls short of an equivalence relation. Note that Linear fractional transformation redirects to Mobius transformation, presuming the complex field. Since the areas of mathematics are richly linked, why are you asking for a "self-contained theory"? The group generated by multiplicative inverse and affine transformations over a ring is a useful concept as shown by references.Rgdboer (talk) 03:25, 17 December 2012 (UTC)
"Self-contained theory" is probably not the right thing to say. Here is what I'm trying to get at. As it stands, it rather looks like the contents of inversive ring geometry are WP:SYNTHESIS of several ideas that do exist in the literature. Of course, synthesis would not apply if these ideas were unified under some sort of heading in a few reliable secondary resources. That's what I'm trying to determine with my questions.
I do find the contents interesting, by the way, but I'm trying to determine whether or not they are appropriate to include as an independent article by WP's standards. Rschwieb (talk) 14:10, 17 December 2012 (UTC)
See Talk:Projective line over a ring#New title. Significant steps have been taken.Rgdboer (talk) 21:29, 1 March 2013 (UTC)
Well done! This term definitely shows up on googlescholar immediately, and while I haven't read the sources, the term is very transparent, and I gather that it is what they are talking about. It is certainly a more transparent title, and now I believe that the topic really does have a foothold. Thanks for making that improvement. Rschwieb (talk) 22:10, 1 March 2013 (UTC)

motor variable[edit]

Hi again. I don't mean to split attention between this section and the ongoing last section, but my question is somewhat similar. I could use your guidance again as to where the term "motor variable" appears in the references, and which references are the reliable secondary resources. Thank you. Rschwieb (talk) 14:21, 18 December 2012 (UTC)

Three references in this article frame the subject: Catoni, Boccaletti, Cannata (2008) "functions of a hyperbolic variable", Vignaux (1935) "funciones de una variable compleja hiperbolica", and Scheffers (1893) "generalization of the usual complex functions" (in translation). The article title might be Split-complex variable. The term motor is adopted from W.K. Clifford’s "Preliminary sketch of Biquaternions" (1873). It can be found at page 181 of his Mathematical Papers (1882), with motor defined at page 185, and put on a par with "biquaternion" in a chart at page 188. Clifford’s article is on algebraic kinematics and responds to Robert Stawell Ball, originator of screw theory. As the screw theory has survived, Clifford’s motors have given way to other views of biquaternions. Since biquaternions are often the earliest context in which students see split-complex numbers, adoption of the term motor was motivated.Rgdboer (talk) 21:48, 18 December 2012 (UTC)
Thank you for the constructive criticism. Some secondary references have been moved inline. Those remaining at the foot are original.Rgdboer (talk) 02:59, 19 December 2012 (UTC)
Unfortunately, "euphony and tradition" are not necessarily valid reasons for this choice. It would be most desirable to use the most widespread and recognizable term for the topic, even if its creator used a different word. At the WP:MATH talkpage, we are testing the idea that it might make sense to have articles on functions of a hypercomplex number in a single article, since it looks like there is good support for that topic. While real and complex analysis are huge and well-known, the reaminder of hypercomplex function study does not seem to warrant splitting into both "motor" and "quaternion" variable articles. Separately some might complain they are given undue weight, but together I think they would make a good article. Rschwieb (talk) 14:41, 19 December 2012 (UTC)
Since we last left this conversation, I've had a chance to do some background on quaternion and hypercomplex analysis. Before I had said that quaternion analysis could be lumped together, but now I feel it could probably remain separate. I notice you have recently created a new article: hypercomplex analysis. I should think that the contents of motor variable belong there, unless you can provide some convincing evidence that they should be treated separately. Rschwieb (talk) 20:28, 6 January 2013 (UTC)

initial context-setting[edit]


Please notice this edit and its edit summary. You need to tell the lay reader that mathematics is what the topic is. You didn't do that. Michael Hardy (talk) 06:21, 6 January 2013 (UTC)

Very good point. Thank you for making the edit. Except in biographies, a common feature of lead sentence construction is a prepositional phrase such as "In mathematics, ..." in this case. Recalling this, I had intended to make the contextual introduction for the lay reader, but came back finding it done.Rgdboer (talk) 21:57, 6 January 2013 (UTC)

Interesting "See also" link to Monadology#Controversy in rationalism[edit]

Hallo there Rgdboer (talk),
wow! That was an interesting link!. Please keep up the good work.. thank you!   M aurice   Carbonaro  07:35, 9 March 2013 (UTC)

Question about the diagram of circular and hyperbolic angle[edit]

There might be a mistake in the diagram of circular and hyperbolic angle: File:Circular and hyperbolic angle.svg.

Angle size and sector area are the same when the conic radius is Square root of two. This diagram illustrates the circular and hyperbolic functions based on sector areas.

Would you like to join the discussion on Talk:Hyperbolic_angle? Thanks.

Armeria wiki (talk) 03:23, 9 June 2013 (UTC)

The areas are not the same, so u has different values in the circular and hyperbolic case, as realized in the discussion.Rgdboer (talk) 20:26, 7 August 2013 (UTC)
Explanatory caption has been added to the diagram.Rgdboer (talk) 02:36, 8 August 2013 (UTC)

History of public relations[edit]

Responding to a year-old post you made on Talk:History of public relations. Would welcome any input. CorporateM (Talk) 05:11, 7 July 2013 (UTC)

Hi Rgdboer. I'm having a hard time finding sources for the Modern Era (1990s - 2010) and was wondering if you knew of any good books or academic publications about the recent era. CorporateM (Talk) 22:20, 27 July 2013 (UTC)

Reversion: Rapidity[edit]

I understand if you might disagree with the formatting style (e.g. HTML math vs LaTeX math) since it's somewhat subjective, but I don't feel it's justified to revert all the changes I made, especially considering the original format is far worse than the edited version (and breaks Wikipedia's style policies in just about every single way). In particular, I would prefer to know if there is anything in particular that you didn't agree with in the new format so I can fix that. Thanks. --Freiddie (talk) 22:50, 4 October 2013 (UTC)

Yes, I reverted your edit to rapidity because the markup failed to compile. Instead of seeing the article text, I saw red error messages. When I looked at the markup you had done, there were lines of code beginning with blanks. Apparently you did not Preview your edit, or you would have seen the problem. As the article has many daily readers and was not available in the form you gave, and there was no simple fix to your markup, I reverted.Rgdboer (talk) 21:44, 5 October 2013 (UTC)

I use the MathJax mode on Wikipedia and there were no issues when I previewed it. I will try to find the cause of the problem and fix it. Thanks. --Freiddie (talk) 23:53, 5 October 2013 (UTC)

Alright I redid the formatting: Rapidity. For whatever obscure reason the renderer on WP's server has like a ~1/6 chance of failing on the markup for unknown reasons, but slightly altering the whitespace in the code "fixed" it. I suspect it's some cache-related bug on WP's end, but I didn't look much further. If the pages are still not working for you, please let me know what OS/browser combination you're using so I can attempt to reproduce the issue. --Freiddie (talk) 00:41, 6 October 2013 (UTC)

OK. Your edit looks clean now. Thank you.Rgdboer (talk) 20:25, 7 October 2013 (UTC)

WER-Editor of the Week Award[edit]

Back in Dec of 2013 you made a comment @ WER talk about how the EotW awards were counter productive. I made a rather snide comment and moved on [5]. The funny things is that, at the time, I had forgotten that I had nominated you to receive the award back in early November. You are in line to receive the award in about 3 weeks...Wikipedia:WikiProject Editor Retention/Editor of the Week/Accepted nominations...unless of course you would rather not. The award is intended to be a simple pat on the back for a job well done. Nothing more. I hope you will reconsider and allow us to present you with the award later this month. You deserve it! ```Buster Seven Talk 18:51, 15 January 2014 (UTC)

Thank you. I take your words and nomination as a compliment. What harm could accepting do? I think of the other 100,000 WP:Users that are also investing their time and best efforts in this project. My contributions are often in scientific areas, and science is something of a churn, so the contributions stand or fall on the writing or references brought forth. Our collaborative efforts have an advantage in the near-anonymity of authorship since content is out front, not the author's identity. It is quite fulfilling to serve readers, some arriving from a Google search, and I would like to continue. The EoW designation could be distracting from the normal contacts through articles and talk pages. Please carry on with other editors in the EoW program; it may have an effect on editor retention.Rgdboer (talk) 02:24, 16 January 2014 (UTC)
Thanks for all the hard work, award or not. I started Wikipedia Editor Retention two years ago with no clear idea of what the project should look like, but I had a lot of faith in the people around me that we could at least do something. Most of what we do never is seen by anyone and doesn't make the pages on the Project. The Editor of the Week program is one of the more visible efforts. In my opinion, the greatest thing to come from the program isn't the individual awards as much as the program fosters the idea that we should treat everyone with "thanks" every day, in all they do. Just as with the entire project, the goal is simply to create greater awareness and appreciation in general, especially for those that work in their own corner of the Wiki, avoiding the spotlight, and doing good things simply because they want to do good things. We will never be able to thank everyone that deserves it, but maybe we can plant seeds to make us all a bit more tolerant, a bit more thankful. Dennis Brown |  | WER 19:27, 13 June 2014 (UTC)
Thank you too Dennis Brown for fostering good attitudes in this democratic experiment. As for gratitude, note the tag on editorial that reminds us that many places do not have freedom of expression. In despotic hands, a publication with an editorial may have ominous tone. Retaining editors is a lofty goal, best wishes in your efforts.Rgdboer (talk) 22:55, 17 June 2014 (UTC)

Split-complex number[edit]

I explained the reason for removing the Warmus material at Talk:Split-complex_number#Interval_arithmetic: Warmus does not use the term "split-complex", and I gave reasons for believing that his interval numbers are not in fact split-complexes. In your revert [6] you simply say "Reference verified". What does that mean? That you checked that it exists? Or do you claim that my reasons for removing the material were wrong? Anyway, please explain and engage in discussion, not here, but at the article talk page. Deltahedron (talk) 21:19, 9 September 2014 (UTC)

Edits by タチコマ robot[edit]

Hello White Cat. Your work eliminating double redirects has done a speedy job with articles that redirected to linear fractional transformation while a discussion was had at Talk:Linear fractional transformation. After discussion the Redirect to Mobius transformation stands reverted, so now the work of White Cat Bot on six related pages must be undone. May I suggest that White Cat Bot be programmed to detect Talk discussion and delay its action to prevent this type of extra effort.Rgdboer (talk) 20:53, 24 September 2014 (UTC)

It is very difficult to assess intent based on talk page messages. Bot wouldn't be able to distinguish if it is the redirect that is being discussed or something else. I am not saying this is a bad idea but I am unsure about the practicality. The bot will re-correct any new double redirects after the revert of its edit on next double redirect scan by MediaWiki. This happens infrequently so it may take about a day or two at times (depending on server load I believe). -- A Certain White Cat chi? 04:37, 26 September 2014 (UTC)

Ramanujan; Tripos of 1898[edit]

It was good to find you had applied your Miltonic principles to the entry for R. A. Herman. Please do not feel in any way obliged to restore any of the text you thoughtfully removed, even if you find that it does all check out as written. I am sure no one is really that interested in Herman, and it is quite customary to leave out whole chunks of a biography. For example, in the numerous tellings of the story of Ramanujan, few if any notice that Hardy and Walker had that prior history. — Preceding unsigned comment added by (talk) 10:32, 9 November 2014 (UTC)

Tripos of 1898[edit]

I note further activity on your part in editing the entry for R. A. Herman. Do you understand that in editing out material that it was presumably you had put in, you might appear to be acknowledging that you had no source for it? How did it come to be there? Surely, if you had reason for thinking the assertions correct, a better way of editing would be to provide a reference. You may have been confusing the responsibilities of a tutor in College with the services of a coach, one who might, at this juncture, be a member of the same College, even a College fellow. You were, however, incorrect in placing JHJ third wrangler when he was bracketed second, with Cameron of Caius. — Preceding unsigned comment added by (talk) 15:33, 11 November 2014 (UTC)

Walker and Jeans: undertook vs. understood[edit]

I am now getting a fuller picture of your editorial - and reading - capabilities. GTW gave an undertaking to JHJ and GHH; ``understood" here makes nonsense of the passage. But I can understand now why you might delete perfectly accurate information on spurious grounds. But I can also see that you view the entry for R. A. Herman as your baby, so it is just fine that you take such good care of it. — Preceding unsigned comment added by (talk) 15:34, 11 November 2014 (UTC)

See WP:Ownership of articles for concept of stewardship.Rgdboer (talk) 21:21, 14 November 2014 (UTC)

Russ Baker[edit]

Main article: Russ Baker (pilot)

User:Heidibakerk posted the following:

Hello I would like to know why you erased what I wrote under my grandfathers page, Russ Baker, I am his granddaughter and I think I know my family history better then you do , I could say what you have written here about your family is all a lie, and I could erase all of it like you did to my Granfather's page. I am his granddaughter I think I know my family history better then you and I gave photos to prove it, I see no photos here on your family , so everything you have written could be a lie on this page !!

Efforts may be made to confirm what has been posted on Russ Baker's article. Apparently this new WP:Wikipedian is not yet familiar with requirements for sources in the project, and has so far not participated in WP:Talk. These provide standards of communication in this project.Rgdboer (talk) 20:21, 29 November 2014 (UTC) The same user posted this:

So Rgdboer are you a person or a robot who keeps erasing what I write about for my grandfathers page Russ Baker, truly not sure how to talk to you on the wiki , you must be human if you have great grandparent or do robots now have grandparents would you mind telling me why you keep deleting my factual information.....

Please refer to Talk:Russ Baker (pilot) for progress on this issue.Rgdboer (talk) 03:38, 2 December 2014 (UTC)

Angle of parallelism[edit]


You removed the reference to Bonola's book in angle of parallelism, I was thinking, given that the google book reference only links to a description of the book (not to a readable copy of the book ) is it not reasonable to also include a reference to the printed book by Bonola? (okay the two references I added to it was a bit over doing it, one reference like you did it is better ) Friendly greetings WillemienH (talk) 00:51, 9 February 2015 (UTC)

Hello WillemienH:
The Google book link is in fact a readable copy of the book. Scroll down from the description and click on pages listed or key terms.Rgdboer (talk) 00:43, 10 February 2015 (UTC)

Hello Rgdboer: the Google link only gives a snippet view of the book, not whole chapters or even complete pages (in my case that is ) (and Bonola's book iis also good for other points), hope you can agree whit the current version, Ps I was also puzzeling with the Napierian Logharithms that Lobachevsky mentioned, does he mean Napierian logarithm or Natural logarithm? Lobachevsky calls it Napierian, but if I am correct, the original base of the Napierian logarithm is between 0 and 1 so not as he mentions > 1, any ideas / comments on this? WillemienH (talk) 20:08, 10 February 2015 (UTC)

See Talk:Angle of parallelism#Napier ?.Rgdboer (talk) 02:10, 11 February 2015 (UTC)


I added refereces to , i am also thinkting to rewrite the article to give less prominence to the text from Halsted especially I think "This publication became widely known in English after the Texas professor G. B. Halsted produced a translation in 1891. (Geometrical Researches on the Theory of Parallels)" is a bit overstatement (or in need of references), I think that in those times knowledge of german was quite common for mathematicians. WillemienH (talk) 23:01, 16 March 2015 (UTC)

Yes, you have noted two faults with the text. It is only of historic (for English readers) importance. Several other references have now been collected, and we are looking forward to more from you. The demonstration given relies on the analytic geometry of the half-plane model, so motivation for the angle=of=parallelism function on a more primitive basis, as Lobachevski and others have done, would enhance the appreciation of that article.Rgdboer (talk) 02:16, 17 March 2015 (UTC)


At first glance I don't see anything in your new Hypersphere to justify forking from n-sphere (to which it until recently redirected). —Tamfang (talk) 03:58, 19 February 2015 (UTC)

See Talk:Hypersphere#Embedding.Rgdboer (talk) 02:13, 20 February 2015 (UTC)

Minkowski space[edit]

You said: "One day I noticed that if the i, j, and k in the quaternion group were given +1 for their squares, then one obtains a quasi-group of order 8, and the real algebra over this quasi-group has many features of Minkowski space." Would you mind explaining the quasi-group of order 8 to a mathematical amateur? This finding could be very useful (assuming I can understand it)... TIA. Rjowsey (talk) 07:39, 11 June 2015 (UTC)

The articles quasigroup and hyperbolic quaternion expand the idea. The particular quasigroup is listed as an Example in the Quasigroup article. Loss of associativity (compared to a group) inhibits the utility for transformation theory, but the hyperbolic quaternion algebra precipitated a major debate among English-speaking mathematicians. See A History of Vector Analysis (1967).Rgdboer (talk) 21:07, 11 June 2015 (UTC)
Thanks. Rjowsey (talk) 21:13, 11 June 2015 (UTC)

Quaternionic analysis[edit]

I tried one of the https links to the Cornell site. First, my browser didn't recognize the certificate. When I bypassed that, the link still didn't work over https. The same link then worked when I changed https back to http. It seems the Cornell server is not configured to support https for those links. — Carl (CBM · talk) 01:46, 17 July 2016 (UTC)

The article HTTPS has some information on this topic. — Rgdboer (talk) 22:59, 18 July 2016 (UTC)


Why do you want to spell Caltech wrong? Gah4 (talk) 23:35, 23 August 2016 (UTC)

The spelling Cal Tech is in a quotation from Theodore von Kármán in his autobiography The Wind and Beyond. Since it is in a direct quotation, there is no correcting it, but rather, as seen in your edit, a [sic] inserted editorially. The strange spelling was noted by one of the reviewers of the autobiography. Lee Edson prepared the manuscript for publication after Theodore's death; he is responsible for this irregularity. — Rgdboer (talk) 20:46, 24 August 2016 (UTC)

Protein combining - user ErinMOBrien[edit]

Thanks for the vote of confidence. I've very concerned about all of ErinMOBrien (talk · contribs)'s edits to date. Any chance you've looked at others from the account, or would be interested in doing so? --Ronz (talk) 14:41, 30 September 2016 (UTC)

Nevermind. All the edits from the account have been removed already. I didn't realize that only one was left when I wrote the above. --Ronz (talk) 17:18, 30 September 2016 (UTC)