User talk:AxelBoldt

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Please add new comments at the bottom. I will reply on this page. If I wrote something on your talk page, please reply there. The idea is to make quoting easy and keep conversations in their logical order.

Older talk can be found in User_talk:AxelBoldt/Archive.

Hi Axel: I am trying to find out who originated the page for the Goedel's incompleteness theorem. My interpretation of its History page suggested to me that it was User:Maveric149, but he said he thought it might be you.

I am thinking about making a change to what appears to be something that has been there since the beginning of that page, and if you are the originator, I would like to first ask your opinion about this. I find that the notation under the proof sketch to be a little awry. In particular, for example, the notation G(F) should be G(F(x)). I don't want to go into a lot of detail here if you are not the right person, so I would appreciate it if you would clarifiy that for me first.

Best wishes, User:BuzzB Apr 3, 2003

Hello Axel,

Thank you for correcting the PMBOK entry.

I'm looking for volunteers to develop a GNU Free Documentation License Project Management Standard (just like the PMBOK, but possibly better). What do you think about it? User:Mkoval Apr 3, 2003.

Hi Axel:

Thank you for your reply to my previous message. It is not my intention to be predantic, but I think my proposed changes make the sketch slightly easier to understand. In addition to notational changes, and the adding of some clarifying text, I changed "proven" and "unproven" to "proved" and "unproved" because I could not find "unproven" in my dictionary. I will reply on your opinion about whether my proposed changes are useful before making them. My proposed revision is below. I have underlined my changes to highlight them.

By the way, I am currently working on a short paper which reconsiders the incompleteness theorem in the context of a three valued system where the three truth vlaues may be interpreted as TRUE, FALSE, and PARADOX. I wonder if you might be interested in reading it.

Proof sketch for the first theorem

The main problem in fleshing out the above mentioned proof idea is the following: in order to construct a statement p that is equivalent to "p cannot be proven", p would have to somehow contain a reference to p, which could easily end in an infinite regress. G�del's ingenious trick, which was later used by Alan Turing to solve the Entscheidungsproblem, will be described below.

First of all, every formula or statement that can be formulated in our system gets a unique number, called its G�del number . This is done in such a way that it is easy to mechanically convert back and forth between formulas and G�del numbers. Because our system is strong enough to reason about numbers, it is now also possible to reason about formulas.

A formula F(x) that contains exactly one free variable x is called a statement form. As soon as x is replaced by a specific number, the statement form turns into a bona fide statement, and it then is either provable in the system, or not. Statement forms themselves are not statements and therefore cannot be proved or disproved. But every statement form F(x) has a G�del number which we will denote by G(F). The choice of the free variable used in the form F(x) is not relevant to the assignment of the G�del number G(F).

By carefully analyzing the axioms and rules of the system, one can then write down a statement form P(x) which embodies the idea that x is the G�del number of a statement which can be proven in our system. Formally: P(x) can proved if and only if x is the G�del number of a statement that can be proved. (While this is good enough for this proof sketch, it is technically not completely accurate. See G�del's paper for the problem and Rosser's paper for the resolution. The key word is "omega-consistency".)

Now comes the trick: a statement form F(x) is called self-unprovable if ~P(F(G(F))), i.e. the form F applied to its own G�del number, is not provable. This concept can be defined formally, and therefore we can construct a statement form SU(y) which embodies the concept: SU(y) is provable if and only if y is the G�del number of a self-unprovable statement form. That is, y = G(F) for some particular form F(x), and ~P(F(G(F))). Then define the statement p = SU(G(SU)). This is the statement p that was mentioned above.

Intuitively, we are now asking the question: "Is the property of being self-unprovable itself self-unprovable?" This is very reminiscent of the Barber paradox: the barber who shaves precisely those people who don't shave themselves, does he shave himself?

If p were provable, then SU(G(SU)) would be true, and by definition of SU, that would make y = G(SU) the G�del number of a self-unprovable statement form, hence SU would be self-unprovable, which by definition of self-unprovable means that SU(G(SU)) is not provable, but this was our p: p is not provable. This contradiction shows that p cannot be provable.

If the negation of p were provable, then, assuming our system to be consistent, p cannot also be provable, i.e. SU(G(SU)) is not provable, and by definition of SU this means that y = G(SU) is not the G�del number of a self-unprovable form, which implies that SU is not self-unprovable. By definition of self-unprovable, we conclude that SU(G(SU)) is provable, hence p is provable. Again a contradiction. This one shows that the negation of p cannot be provable either.

Best wishes, User:BuzzB

Hi Alex:

I uploaded a revision in which I accepted your suggestion to leave the text with G(F) rather than G(F(x)), but I added some explanatory text.

I just printed out a copy of the Goedel proof from the web page reference, but I haven't had time to re-read it yet. Off hand, I tend to agree that the "only if" should be removed. I'm not sure I get the connection with inconsistancy, although if there is a connection then of course every statement would be provable.

Regarding my paper on a three valued interpretation, it is a work in progress. I don't expect to have a complete draft for a while yet, but if you would like me to send yoi a sketch of what I have in mind, I would be happy to do that.

Best wishes, BuzzB

Hi Alex:

I think your edit to the proof sketch is a very good improvement.

I finally got my personal web site up. There is a link on my User page. I would appreciate any comments you would care to make about anything I have there. When I complete a draft of the paper on a three valued re-intepretation of the Goedel theorem, I will post it there.

Best wishes, BuzzB

Many of your math entries (I was reading the one on the Open mapping theorem) can't be understood unless one is already studying that field of mathematics, or a similar topic. Could you define some of the terms that you use in the article? LittleDan

Re: Persuasion Technology. A bizzarre, rambling document. I tried paring it down to make it clearer some months back. Not that fuzzy thinking is much improved by fixing grammar. I had hoped the author would take the hint to de-ramble it. Instead, the author immediately restored the original text verbatim without comment. So I put the NPOV dispute at the top and watched. If the author is now banned, perhaps you will fair better. User:Williamv1138:Williamv1138

Axel, I am writing to you because you have been active in Wikipedia for a long time. I have been in an edit war with JTDIRL and 172 on the China page, and I think there is both a need for some intervention, and an intervention that is not based on any argument about China, but rather about Wikipedia conventions, especially NPOV and naming conventions. I wrote to Mav who made a very brief and in my opinion constructive comment on the talk page a couple of days ago, although nothing has come of it. I have thought of asking some others, but you are one of the most experienced people here. And, as I said, I think what is most needed now is some explicit discussion of Wikipedia conventions.

To fully gradp the debate behind the edit war you would have to read a lot. Minimally, I would suggest reading the entire Talk: China (Archive 3) and Talk: China pages (which I know is a lot to ask of someone who may not be so interested. As a party to the dispute and biased, I don't want to misrepresent it, but I will try to sum it up.

The question is, how to identify the Chinese (specifically, PRC) state. The article identified the state as communist. I checked the Chinese Constitution which states that it is a socialist state; an official Chinese website states that it is not a communist state. JTDIRL and 172 responded that all political scientists identify China as a communist state and that we should go by what Western scholars do. I talked to a few colleagues of mine -- a sociologist, two anthropologitsts, and a political scientist. They told me that many political scientists used to label China a communist state but that they are moving away from that designation, considering it inaccurate and meaningless; that many political scientists and most other scholars identify China as a socialist state, although some qualify it as "late" or "post" socialist. Now JTDIRL claims that it doesn't matter what political scientists say, that what ought to be presented is a "formal encyclop�dic definition."

Now, I never heard of this phrase and doubt that it should be the basis of our deciding how to identify any state, as what we are trying to do is, arguably, devise a formal encyclopedic definition. I think he means we should call it a communist state because other encyclopedias do. I still think we ought to call it something that reflects the current state of scholarship.

But I hope you can see why I think this is a matter of clarifying general wikipedia conventions or norms, and not just a debate over China. And I hope you understand why I have turned to you.

I am not asking anyone to say "SLR is right and JTDIRL is wrong." I am asking the community, such as it is, to discuss the conventions and clarify them as they may apply to the case.

If you do not feel comfortable doing this, but understand why I bring it up, could you post this on the listserve for discussion? Either way, I appreciate your reading this far! Slrubenstein

Thanks for trusting me with this -- I don't want to get involved however. I'll post it on wikien-l (http://www.wikipedia.org/pipermail/wikien-l/). AxelBoldt 04:45 Apr 25, 2003 (UTC)

Thanks -- I understand, and appreciate it, Slrubenstein

Hi, From the page history I see that you're a main contibutor to the Euler pseudoprime page, I'd be in favour of moving the page and have given my reasons on Talk:Euler pseudoprime. I thought you may like to comment. Cheers -- Ams80 11:50 May 8, 2003 (UTC)

TeX Etymology

Why is it called TeX? Surely the name of such a useful tool must have a significance, doesn't it? This information would interest the reader. I Googled a bit and couldn't find out anything. --Menchi 19:30 May 13, 2003 (UTC)

I don't know the etymology, but I agree it would be interesting to know. It's possible that "TeX" is just a variation on "text" though, with fancy letters and pronunciation. I would think that Knuth gave his reasons in the TeX book. AxelBoldt 20:46 May 13, 2003 (UTC)

Found it. Have included in the article. --Menchi 20:15 May 15, 2003 (UTC)

Nice. I noticed that you use font=symbol for tecne. It would be better if you used the greek HTML characters directly (wikipedia:How to edit a page), since the symbol font only works on Windows. Cheers, AxelBoldt 20:39 15 May 2003 (UTC)

Hi Axel. One of your references in the linked article refers specifically to Columba livia, and it seem improbable that the other items refer to a different species (although it's a long time since I had to study F X Skinner) so I've moved it to Rock Dove. If I've got it wrong, please move it back. If you think it should be in both articles anyway, please make it clear it's Feral Pigeon in the group article. thanks jimfbleak 17:25 May 15, 2003 (UTC)

Hi Axel!
Thanks for noticing I hadn't named the painter (Renoir) in the Impressionism article. I can't believe I did that!
Adrian Pingstone 15:48 16 May 2003 (UTC)

Axel, I'm no maths guru, but I confess to some suspicion of User:Stupidmoron's contributions so soon after the other nonsense, now deleted. Mind running an eye over them? Tannin 13:43 20 May 2003 (UTC)

Thanks Axel. That's good to know. Tannin

______

Hi there - you had a slight factual error in the resignation of Otto von Bismarck. He was actually dismissed by the Kaiser, rather than as a result of the gains of rival political parties as you suggest. Dare I be cheeky and ask for the W1 you have offered for factual errors? - David Stewart 09:06 21 May 2003 (UTC)

Great, thanks. W1 is on its way. AxelBoldt 19:12 21 May 2003 (UTC)

Many thanks! - David Stewart 01:31 22 May 2003 (UTC)

Axel,

I just noticed that you posted a question a month ago to my talk page about my additions to the quaternion entry. ... I've written up a response there. Steven G. Johnson (Jun 9 2003)

Axel, I put a new proposal for naming of symbolic logic. Definetely you know more about math and give me comments if you don't mind. Cheers! -- Taku 15:31 31 May 2003 (UTC)

Hi, found this (http://art-bin.com/art/medhistorypix/omedicalimages.html) on one of the blogs I frequent, and thought you might know what to do with it, if anything. Koyaanis Qatsi

Hello Axel, I fixed a couple of minor factual errors on Otto von Bismarck. Since that's listed on User:AxelBoldt, does that earn me the Wikipedia:WikiMoney you pledged? :-) -- djmutex 10:50 4 Jun 2003 (UTC)

Sure, thanks! AxelBoldt 18:04 4 Jun 2003 (UTC)

Hi, Axel,
I'm no mathemetician, but you are, so I come hat-in-hand asking for a favour. The constellation of contributions at neutrosophy, neutrosophic set, Florentin Smarandache, outer-art, the contributions of new user "Lit-sci" (http://www.wikipedia.org/w/wiki.phtml?title=Special:Contributions&target=Lit-sci), the contributions of 64.106.24.51, which maps to University of New Mexico Gallup Branch (http://www.wikipedia.org/w/wiki.phtml?title=Special:Contributions&target=64.106.24.51), and of 64.106.24.53, of that same institution (http://www.wikipedia.org/w/wiki.phtml?title=Special:Contributions&target=64.106.24.53) lead me to suspect we're being scammed into covering a fairly idiosyncratic concept as though it were generally accepted. Is this something more than say 50 people have heard of/found useful? I'd be interested in your comments. -- Someone else 20:49 4 Jun 2003 (UTC)

On the contrary, I thank you for having the knowledge and inclination to set it all in its proper context! -- Someone else 23:12 5 Jun 2003 (UTC)

Thanks for that Axel - I had ever confidence somebody knowledgeable would come along and fix it eventually :) Martin

Very nice work on Gertrude Stein, which I hope was more enjoyable than the equally-appreciated-though-undoubtedly-more-gruelling grunt work you've been doing on the Smarandistas. -- Someone else 23:52 9 Jun 2003 (UTC)

Hi, could you take a look at DXM when you get a chance? I tried to correct the formatting and convert fragments to sentences, but I left parts of it alone because I didn't know how to change them, being generally unversed in the subject. Thanks. Koyaanis Qatsi 05:39 12 Jun 2003 (UTC)

DXM looks much better now, thanks. Glad you liked the wikien missive; Eclecticology has given me an idea--maybe with some practice I could be a comedy writer. ;-) Koyaanis Qatsi 20:57 12 Jun 2003 (UTC)

Would you mind explaining your changes to limit (mathematics)? Pizza Puzzle

yes but from "division-by-zero" you cut:

In cases where substitution results in 0 / 0, a limit probably exists; in other cases (such as 17 / 0) a limit is less likely. For instance; if f(x) = x³ + 1 / x - 1; then, if one substitutes 1 for x, one will obtain 2 / 0; the limit of f(x) (as x approaches 1) does not exist, as f(x) is unbounded
- this should be rewritten to state, "the numerator is 0" rathern than " 0 / 0" but I do not think it should be cut. Pizza Puzzle

and (x² - 6x) / x involved a notably different technique than (x³ - 1) / (x - 1) , which I argue to be just as "nice" of a technique

and, yes, the absolute value definition duplicates a paragraph further down in the formal section, but it does so informally which makes it far more useful for the neophyte reader Pizza Puzzle

The statement "In cases where substitution results in 0 / 0, a limit probably exists; in other cases (such as 17 / 0) a limit is less likely." is simply false: 0/0 may or may not exist and 17/0 never exists. We have examples of both cases.

The technique for the two example functions is the same: use algebra to rewrite your function until you can plug in c. AxelBoldt 21:25 18 Jun 2003 (UTC)

You also deleted the section on one-sided limits. Pizza Puzzle

1.b4 (Your move!) You also deleted (at product rule):

Development of this rule is credited to Leibniz; who demonstrated that (x + dx)(y + dy) - xy = x(dy) + y(dx); as (dx)(dy) is "negligible".
- As sources I offer The History of Mathematics by Burton and Calculus of a Single Variable: Early Transcendental Functions (3rd Edition) by Edwards, Hostetler, and Larson

Is this not true?

Oh yes, I meant to put that into a history section, maybe with a little bit more information, then I forgot about it.

Also, I am of the understanding that this is the Product Rule; not merely a product rule. Pizza Puzzle

Yes, but in the math arena we decided a while ago to use lower case throughout, for instance Fermat's last theorem. I agree it's a bit strange. 1. ... c6. AxelBoldt 15:27 19 Jun 2003 (UTC)

If everyone agrees its "strange" (I havent heard anybody actually support it) why continue to do it?

Well, some math books use the lower case style, and there's a general tendency to use lower case in titles, because in article texts people are much more likely to write "product rule" than "Product Rule".

Doesn't f(x) = (x2 - 1) / (x - 1); have a discontinuity?

No: the function is continuous at each point of its domain, which doesn't include 1.

1.b4 c6 2.c4 Pizza Puzzle

2.... d5 AxelBoldt 04:18 21 Jun 2003 (UTC)

Yes, f(x) is continuous at each point of its domain; but, the function has a discontinuity at x = 1; thus, the domain of f(x) is all real numbers except x = 1. Or so I understand...

1.b4 c6 2.c4 d5 3.e3 Pizza Puzzle

The Wikipedia articles on the laws of non-contradiction are not as clear as they could be. Would you mind taking a look at the articles on Law of excluded middle and Law of non-contradiction? I was wondering if we could give an example showing how the these are similar, and how they are diferent; Functionally, when are they practically identical? What examples can best show us the differences between what these laws? RK 00:28 28 Jun 2003 (UTC)

moin Axel! sorry f�r die sp�te antwort.. ganz ehrlich habe ich den artikel de:Walletjes damals (in meiner newbie-zeit bei wikipedia) ganz aus dem kopf heraus geschrieben. ich bin mir wirklich nicht mehr ganz sicher woher ich diese info hatte, ich denke das kam von einem freund der ein paar jahre in amsterdam wohnte.. (zu meiner schande habe ich damals auch nicht wirklich nach-recherchiert). wenn du dich da besser auskennst �ndere es bitte! gru�! pit 16:38 2 Jul 2003 (UTC)

I thought you might be interested in the opinion poll going on now at Talk:Clitoris. MB 18:08 9 Jul 2003 (UTC)

How about a making fun of Barnes & Noble? This page (http://video.barnesandnoble.com/search/glossary.asp?userid=53XT7V6C94&LTR=C&TRM=1004639) conflates cinema verite with Dziga Vertov's Kino Pravda as well as Robert J. Flaherty's heavily fictionalized work; it claims verite has no director (!? WTF) (Flaherty himself directed quite a lot--having an igloo made with a side cut away to allow enough light for him to shoot the end of Nanook of the North, and cutting in the footage of the family inside the partial igloo to make it look as if they had built shelter just in time to avoid a blizzard--and in an earlier scene insisting that Nanook et al. hunt with harpoons instead of rifles); the page also claims that cinema verite did not use a script, making its inclusion of Vertov doubly misleading--Vertov had planned quite a bit of Man with the Movie Camera, though he may not ever have written it out in script form. Also the "real life" B&N mentions on camera hinges on Vertov's two phrases "life caught unawares" and "life as it is," which are commonly confused for each other and actually mean two distinct things. In short, I would say the last two sentences of the B&N article can go without qualification; the previous two need serious qualification; and the rest is crap. Koyaanis Qatsi 02:21 15 Jul 2003 (UTC)

Axel, could you look over the most recent changes to Turing machine? Personally, I think the article is considerably less accessible and a less useful introduction since the introduction of the "mathematical formulation". --Robert Merkel 05:57, 7 Aug 2003 (UTC)

Hi Axel,

I like your bookmarklet for searching Wikipedia, but I want to adapt it for phrase search. I tried (for IE)

javascript:s=(document.frames.length?'':document.selection.createRange().text);for(i=0;i<document.frames.length;i++){if(s)break;s=document.frames[i].document.selection.createRange().text;}if(!s)void(s=prompt('Enter search terms for Wikipedia:',''));wikiw=window.open('http://wikipedia.com/'+(s?('wiki.phtml?search='+'"'+escape(s)+'"'):''));wikiw.focus()

i.e. putting the phrase in quotes, e.g. for "closed and reclaimed" I get

http://www.wikipedia.org/wiki.phtml?search=%22closed%2520and%2520reclaimed%22

which does not work; using the wikipedia search box one gets

http://www.wikipedia.org/w/wiki.phtml?search=%22closed+and+reclaimed%22

which gives the right result.

http://www.wikipedia.org/w/wiki.phtml?search=%22closed%20and%20reclaimed%22

works also.

Do you know I should change the bookmarklet?

Patrick 11:55, 8 Aug 2003 (UTC)

Hallo Axel. Mir sind einige Ungereimtheiten im Artikel zero divisor aufgefallen, die ich in der dortigen Diskussions-Seite dargelegt habe. Vielleicht hast du ja Zeit, den Artikel zu ueberarbeiten. -- SirJective 10:52, 12 Aug 2003 (UTC)

Danke, so gef�llts mir. Auf die Sache mit den Produkten von Linksnullteilern h�tte ich ja selbst kommen k�nnen! *g* Da ich seit diesem Artikel einen Account in dieser Wikipedia habe, kann ich kleine Sachen auch selbst �ndern. Gr��ere Probleme werden nach wie vor zur Diskussion gestellt. --SirJective 19:56, 29 Aug 2003 (UTC)

Hi Axel. I just saw your May 22 edit of the property table at Nitrous oxide. In the future could you please make a note of your opinions on the tables at Inorganic table information, and perhaps even edit the template table there? I'm trying to keep all the tables consistent, but it's a bit hard to watch all 40 of them for edits. Also, I note you have been adding CAS numbers. Do you think it would be a good idea to include them in the table, underneath the formula? -- Tim Starling 02:26, Aug 21, 2003 (UTC)

Did you get my email regarding an emergency developer contact list?

Axel, check out the new proposal at Talk:Ethics; this looks like it should fix things in regards to that article. Your thoughts? RK 22:21, 31 Aug 2003 (UTC)~

See . -- Tarquin 12:03, 11 Sep 2003 (UTC)

Circumcircle :-) (and the triangle image doesn't show in the triangle article -- just the link as text. I can't work out what's wrong with it Tarquin 15:01, 11 Sep 2003 (UTC)

Can you help me with something in math? I know this question is not wikipedia, but you're a math professor, so I though I could ask you. If I can't, that's OK. I'm trying to learn first-order predicate calculus from a book I got in my local library, and I understood most of it, but I just got stuck. Right now, they are proving that predicate calculus is complete, so they are working with tautologies in the process. I don't understand the difference between the truth of a statement and if it is a tautology. I don't know why they are reproving things like modus ponens with tautologies instead of proofs, and subsequently I don't understand these proofs (they are just in English, not in any formal mathematical statement). The tautology article doesn't offer much help and neither does MathWorld. Am I in over my head? LDan 01:52, 29 Sep 2003 (UTC)

There's a subtle difference between true statements about predicate calculus, and tautologies. The following is a true statement about predicate calculus:

Whenever p→q holds and p holds, then q holds as well.

This is not a statement within the predicate calculus, but it is a statement about the predicate calculus, a so-called meta statement. And it is a true meta statement, called the modus ponens. Now a tautology is a formula within predicate calculus, which holds no matter what the variables stand for. The following is a tautology within predicate calculus

((p→q)∧p)→q

This formula holds always, no matter what you replace p and q with. And obviously, this tautology is closely related with the above meta statement, almost identical (and also sometimes called the modus ponens). In the chapter you're reading, they are probably currently proving these tautologies, assuming the corresponding meta statements. If you don't know the difference, then these proofs may look pointless. AxelBoldt 10:43, 29 Sep 2003 (UTC)

Regarding your question on the heart-and-lung image on nl:, I have forwarded it to the user who uploaded the image. I can only hope he answers - I had sent him a message about another image a few days earlier, and not yet received answer although he has been around. Andre Engels 13:12, 15 Oct 2003 (UTC)

Only now I see I had placed it on his user page rather than his talk page, so maybe there will be an answer after all. Andre Engels 13:16, 15 Oct 2003 (UTC)

Thanks Andre. Whether he answers or not, the episode has already been very fruitful for me: I just found a wonderful wealth of public domain anatomy drawings at http://www.bartleby.com/107/ . Cheers, AxelBoldt 13:40, 15 Oct 2003 (UTC)

While Keating's conviction was overturned on technicalities, he spent 4 1/2 years in prison, and pleaded guilty in April 1999 to reduced charges [1] (http://www.hollandsentinel.com/stories/080799/new_charleskeating.html) which would let him out of prison. I think there were also some new hearings, possibly even a new trial. So I do not consider your current presentation entirely accurate, but I will abstain from editing the article until a conclusion has been reached regarding the basics.—Eloquence 00:32, Oct 27, 2003 (UTC)

Everything is fully explained at Charles H. Keating Jr.. AxelBoldt 00:41, 27 Oct 2003 (UTC)

That article is good, but Mother Teresa should note that Keating spent 4 1/2 years in prison for the Savings & Loan scandal. "Turley's statements have never been proven" is POV -- would Turley agree with that? He would probably say that his statements have been proven, but that the proof was ignored by the higher court on grounds of a technicality. IMHO the whole sentence is redundant with the "overturned" part.—Eloquence 01:00, Oct 27, 2003 (UTC)

The "technicality" was that the jury never determined whether Keating intended to defraud the victims, and that is of course the whole thrust of Turley's statements. In the end, the 50 months Keating spent in federal prison were for a bankruptcy fraud only marginally related to and much smaller than the S&L scandal; his two convictions in that scandal were both overturned. AxelBoldt 02:08, 27 Oct 2003 (UTC)

For the claim "Turley's statements have never been proven", it does not matter what the jury has determined -- it matters which proof has been presented in the case against Keating.—Eloquence 02:23, Oct 27, 2003 (UTC)

Ok, how do you like it now? AxelBoldt 14:02, 27 Oct 2003 (UTC)

Much better, thank you (didn't know about the plane). BTW, Keating is also the producer of Perversion for Profit (http://webdev.archive.org/movies/movieslisting-browse.php?collection=prelinger&cat=Pornography), a notorious propaganda film against porn ("This same type of rot and decay caused sixteen of the nineteen major civilizations to vanish from the earth. Magnificent Egypt, classical Greece, imperial Rome, all crumbled away. Not because of the strength of the aggressor, but because of moral decay from within.") Perhaps also of interest: "By 1960, Keating was testifying before the U.S. House of Representatives armed with, according to a Cincinnati Enquirer article, 'hundreds of books and magazines -- purchased at newsstands throughout the country -- describing and depicting a variety of perverse sexual activities' After Keating's testimony...the House subcommittee burned the mass of material." [2] (http://www.geocities.com/SoHo/Lofts/2613/ccv.htm) —Eloquence 14:17, Oct 27, 2003 (UTC)~

What was wrong with my definition of homeomorphic on Planar graph? [3] (http://planetmath.org/encyclopedia/Homeomorphic.html) seems to agrees with me... Dysprosia 02:02, 29 Oct 2003 (UTC)

Well, it wasn't a definition. If, given the graphs A and B, and B which is an expansion of A, it is often described that A is homeomorphic to B.

The statement is technically correct, but readers could very easily leave with the mistaken impression that this is the definition of homeomorphic. For example, the graphs

    * - * - * - * - *
        |
        *

and

    * - * - * - *
        |
        *
        |
        *

are homeomorphic, but neither is an expansion of the other. AxelBoldt 10:36, 29 Oct 2003 (UTC)

Thanks :) You see, I mistakenly assumed that an expansion and a homeomorphism between two graphs was the same thing... You wouldn't mind if I clarify the homeomorphism terminology, would you? Dysprosia 11:05, 29 Oct 2003 (UTC)

Not at all; maybe a homeomorphism (graph theory) is in order. AxelBoldt 11:15, 29 Oct 2003 (UTC)

Lungs

You ask a subtle question, grasshopper<G>. I, who cannot draw to save my life, drew you a diagram for this one. Have a look at Lung and let me know if my words and pictures have made the interplay between tidal volume and lung capacity more obscure, or less obscure...-- Someone else 17:00, 8 Nov 2003 (UTC)

Statue of Liberty

When I said the torch was open, I meant the crown. Sorry. I hope you won't discredit me forever! -- Mattworld 02:35, 12 Nov 2003 (UTC)

Well, I may grant you one last chance to redeem yourself, if you can find out the status of the torch balcony for me :-) AxelBoldt 14:16, 12 Nov 2003 (UTC)

Hi Axel. It was closed for a while, then opened before 9/11, then closed after the attack. (Just checked with security here. I am right by the ferry and we were closed too). Danny 19:37, 14 Nov 2003 (UTC)

Thanks! AxelBoldt 20:57, 14 Nov 2003 (UTC)

Pic Captions

Hi Axel, just a quick one to ask why "my" caption on Edith Piaf was changed to largish font? I think the larger font looks a little ugly because it's now very slightly larger than the text. I thought that the caption-text produced by the small command had been accepted as looking about right for captions?
Adrian Pingstone 09:53, 16 Nov 2003 (UTC)

Just another thought, have a look at Trainer and imagine how a longer caption would look in that large font!

Adrian Pingstone 10:03, 16 Nov 2003 (UTC)

I think small fonts are difficult to read, especially in italics fonts. Trainer is an example of a caption that has way too much information. AxelBoldt 14:17, 16 Nov 2003 (UTC)

Axel, regarding the two math questions you left on my talk page. The theorem about the dimensions of division algebras is usually stated for real division algebras. I suspect it's capable of some generalization, but I'm don't know for certain. Also, it does apply to fields -- the proper definition of dimension of a division algebra is its dimension as a vector space over its center, so fields always have dimension 1. I do know the most general statement, which is that the dimension of a division algebra is always a square.

Regarding Gelfand-Mazur, since Banach algebras are by definition associative, so trivially Gelfand-Mazur applies to associative algebras. I think Mazur's theorem, and the various generalizations and variants of Gelfand-Mazur that are sometimes also called the Gelfand-Mazur theorem all require associativity. Loren Rosen 22:44, 20 Nov 2003 (UTC)

Thanks, I added the bit about division algebra dimensions being square to division algebra. I also made a couple other changes on that page and on Banach algebra and normed division algebra all having to do with topics you seem to be knowledgable about, so please have a look if you like. AxelBoldt 19:32, 21 Nov 2003 (UTC)

The word is "controversially" [4] (http://dictionary.reference.com/search?r=2&q=controversially). Cheers, Cyan 03:06, 8 Dec 2003 (UTC)

WikiProject Programming languages

Would you be willing to join WikiProject Programming languages, I could really use your help. —Noldoaran (Talk) 03:56, Dec 17, 2003 (UTC)

Thanks, but to be honest I'm not too eager. AxelBoldt 11:52, 17 Dec 2003 (UTC)

Challenge Problems:

Use the algebra of dimension theory to derive both the Planck-Einstein Law (E = Planck constant times frequency) and the De Broglie Law (momentum times wavelength = Planck constant) from the photonic law (wavelength times frequency = constant). Answer: http://members.fortunecity.com/jonhays/dimalg.htm.)

Use dimensional algebra to derive D'Alembert's Principle from Newton's Second Law of Motion, and to derive both D'Alembert's Principle and Newton's Second Law of Motion from The Antitonic Principle. (Answer: http://members.fortunecity.com/jonhays/dalderive.htm.)jonhays 17:23, 19 Dec 2003 (UTC)

I've created a diagram of the human heart similar to the one you linked to on Wikipedia:Requested pictures. No labels or anything yet, but they'd be easy enough to add. I'd welcome suggestions for improvements in coloring and anatomical correctness! It's SVG, so I can modify it fairly easily. Would it help if I produced a series of images showing the heartbeat process? Leave a message on my talk page. -- Wapcaplet 20:02, 20 Dec 2003 (UTC)

I'll go ahead and add labels to the heart diagram, and work up a couple of shots showing the blood flow. I can upload the finished SVG in addition to the exported .png images, so others can modify it for non-English versions. -- Wapcaplet 16:32, 24 Dec 2003 (UTC)

Done. Check it out and let me know what you think. -- Wapcaplet 20:51, 24 Dec 2003 (UTC)

just want to say thanks for the many quality math articles you contributed. I enjoyed them extremely. Xah P0lyglut 14:08, 2004 Jan 7 (UTC)

Axel, could I ask you to look at my latest remark under Talk:Marquis de Sade and see if you & I can get consensus? I don't think we are very far apart at this point, if at all. -- Jmabel 23:27, 9 Jan 2004 (UTC) TNX, looks like we now agree. --Jmabel 06:56, 11 Jan 2004 (UTC)

Neither \begin{eqnarray*}...\end{eqnarray*} nor \begin{align*}...\end{align*} are possible to use inside an equation. Does an alignment markup exists, that can be used inside $$ $$ ? (it'd be simple to add out-of-$$ markup to texvc, I'm just trying not overcomplicate the matter from the users' perspective).

For other stuff, see the recent wikitech post. Taw 23:24, 19 Jan 2004 (UTC)

Contradiction in ordinal number article

Hello Axel.

The article ordinal number contains statements that seem to contratict each other."Ordinals which don't have an immediate predecessor can always be written as a limit of smaller ordinals" contradicts "no sequence of elements in ω1 has the element ω1 as its limit". I have two month ago written this on the talk page, but noone answered yet. Do you know enough about ordinals to help me with this? --SirJective 16:21, 1 Feb 2004 (UTC)

Answer on talk:ordinal number. AxelBoldt 16:14, 2 Feb 2004 (UTC)

Royal Library book thief

In case you missed an answer, please look at http://da.wikipedia.org/wiki/Wikipedia:Landsbybr%F8nden#Royal_Library_book_thief --Christian 14:28, 9 Feb 2004 (UTC)

Thanks! AxelBoldt 14:58, 9 Feb 2004 (UTC)

Review request

Hi. I wrote a couple paragraphs in standard deviation, on interpretation and application. Would you mind looking it over and improving a bit? I've tried but it still feels incomplete and clunky to me. Isomorphic 09:03, 10 Feb 2004 (UTC)

I thought the paragraph was good; I changed only one little thing: we don't usually reject a hypothesis if our measurements are only one standard deviation away from the prediction; more commonly a 95% rule is used, which roughly corresponds to two standard deviations if we assume normally distributed measurement errors. AxelBoldt 02:38, 11 Feb 2004 (UTC)

Re:Linking captions

Sorry, but (right now) wiki does not support linking captions in pictures like that. The preference is that you discuss the picture in the article, and link relavent people/places/thingss from there. →Raul654 18:21, Feb 12, 2004 (UTC)

Random Praise

I just wanted to say that the stuff you've written about Group Theory is the best I've been able to find on the web, and it's more comprehensible than I remember my professor being when I took "Intro to Group Theory" a while back. I wish all my professors could lecture like you write! D0SBoots 00:03, 15 Feb 2004 (UTC)

Thanks! When I cover a topic on Wikipedia, I do try to produce the best stuff available on the web -- else, what would be the point? We would just be wasting our readers' time. Most of the group theory material wasn't written by me however, but by User:Chas_zzz_brown who produced excellent work but unfortunately seems to have left the project. Cheers, AxelBoldt 00:46, 15 Feb 2004 (UTC)

Hi, your search bookmarklet (http://math-www.uni-paderborn.de/~axel/bookmarklet.html) listed at Wikipedia:Searching#Bookmarklets doesn't work with Mozilla. I think you need to change wiki.phtml?search= to /w/wiki.phtml?search=. Angela . 04:08, Feb 16, 2004 (UTC)

Yes, thanks, will do :-) AxelBoldt 14:11, 16 Feb 2004 (UTC)

Hi. Unifying conjecture is listed on VfD by Charles Matthews, who says it's basically nonsense. I'm inclined to agree, but some have expressed a discomfort at relying on the opinion of one expert. Could you take a look and give another expert opinion? Thanks, Isomorphic 21:54, 23 Feb 2004 (UTC)

Hi. I just wrote an article on the short term Fourier transform. Aside from accuracy errors, I would like it if you could help with the relationship to the uncertainty principle, which I have seen connected in various articles online, with conflicting explanations. you were involved in a conversation on the uncertainty talk page, and I figured you would know about the relationship, or could help me find more, accurate, information to write it myself.

Thanks, Omegatron

Here's what I think I know about this: quantum mechanics postulates that the state of a system is described by a vector in a Hilbert space, and an observable (a variable like position or momentum) is modeled by an operator on that space. Given such a state and an observable, i.e. a vector and an operator, one can compute the probability distribution of the outcomes of measurements of that variable. Now from these postulates, one can prove purely formally that an uncertainty principle holds: it relates the product of the uncertainties of two variables to the commutator of the corresponding operators. All this doesn't need Fourier transforms.

Now, this uncertainty principle is completely general; the traditional uncertainty principle however is concerned with particular variables: position and momentum. Position is modeled by the operator "multiplication with x" and momentum by the operator "-i d/dx" (both are operators on the Hilbert space of square integrable functions f(x)). Now it turns out that the Fourier transform of -i df/dx is 2 π s F(s) (if F(s) is the Fourier transform of f(x)). From this, and the fact that the Fourier transform is invertible and compatible with the inner product in L², one derives that the probability distribution of the momentum variable is the Fourier transform of the probability distribution of the position variable. Furthermore, there is a general theorem about Fourier transforms (unrelated to the above theorem about operators) which says something like "the standard deviation of g(x), times the standard deviation of G(s) (the Fourier transform of g(x)), is always bigger than 1/2." (See [5] (http://www.physics.uiowa.edu/~gpayne/teaching/uncert.pdf); this is often called the "uncertainty principle for Fourier transforms".) This then yields an alternative proof of the physical uncertainty principle. The advantage of this proof is that it doesn't need fancy Hilbert space operator magic, and that it gives some intuition behind the uncertainty relation: just like a signal cannot be simultaneously concentrated in time and frequency, a measurement cannot be simultaneously concentrated in position and momentum. The disadvantage of this second proof is that it only works for these particular observables (position and momentum), or slightly more generally for any pair of observables whose operators are related by the Fourier transform. AxelBoldt 13:28, 26 Feb 2004 (UTC)

Uh... You lost me at Hilbert space. Maybe I will go and learn about it someday, but for now I guess I am hardly qualified to write this section of the article... Omegatron 16:03, Feb 26, 2004 (UTC)

As an occasional contributor to the Nivokov self-consistency principle article, I'm hoping that you have some familiarity with Newcomb's paradox. I am asking for informed comment on that article. Thanks for any assistance you can provide. Rossami

Hello, actually I didn't know Newcomb's paradox, but it looks very interesting. I'll read over it and put comments in Talk. Cheers, AxelBoldt 13:14, 20 Mar 2004 (UTC)

Follow-up request for you on Newcomb's paradox. I replied on the talk page and would like your thoughts on what I misunderstood. Thanks. Rossami

Ahhh. I was misremembering the definition of the Nash equilibrium. When the rest of the Newcomb's paradox article stabilizes, I am going to add a few words to try to make that distiction come through more clearly just from the context. Thanks. Rossami

If you have some time, I need some help with Ramanujan modular functions. JWSchmidt 20:03, 24 Mar 2004 (UTC)

Sorry, I don't know the Ramanujan modular function and I certainly don't know its connection to string theory. AxelBoldt 13:40, 25 Mar 2004 (UTC)

Germans

I've for long (a year, actually) been itched by the way Wikipedia-links are done with often sloppy distinctions between nationality, citizenship and ethnicity (with regard to persons) and also between nations and countries. This is particularly obvious in the case of people or entities that are denoted as German. A link to the Federal Republic of Germany is often outright unhistorical and wrong, but this has until now been the most usual.

Therefore I'm considering an article on Germans, which I've started at User:Ruhrjung/Germans. I would wish to avoid lots of edit wars. In particular, I would not wish to see the current disputes over German-Polish matters automatically extend also to this article, why I kindly ask you for comments now, in advance, in order to try to find wordings acceptable to as many as possible of concerned wikipedians.

I look forward to your comments at User talk:Ruhrjung/Germans.
--Ruhrjung 23:33, 14 Apr 2004 (UTC)

Old Request

Axel, I noticed on Wikipedia:Requested_pictures#List_of_Pictures_Requested that several months ago you requested a drawing of the inner workings of the heart. When I checked the article, it has a very good drawing. Is that request still valid or can it be removed from the request list? Thank you. SWAdair | Talk 09:50, 24 Apr 2004 (UTC)

The excellent drawing of heart is a result of my request, so the picture request can be deleted, which I just did. Cheers, AxelBoldt 10:11, 10 Jun 2004 (UTC)

Axel, I just wanted to note that I made a response to an older comment of yours in Talk:Twin_prime_conjecture - Taxman 12:33, Jun 9, 2004 (UTC)

New layout kudos

from the pump

The new page layout is just wonderful: clean, logical, functional and uncluttered. To whoever is responsible for the new design: Thanks for the great work! AxelBoldt 10:26, 9 Jun 2004 (UTC)

Good to hear there's at least one user who likes the new layout ;-) MediaWiki_talk:Monobook.css seems to indicate most would prefer returning to the standard skin... -- Gabriel Wicke 15:24, 9 Jun 2004 (UTC)

Nah, you only hear from the unsatisfied. I went back to standard for a while, but found it crufty and old-fashioned, so I'm back with monobook. I guess 50% of the complaints (and the most bitter) stem from the cache-snafu prone transitional period (and the categories layout bug period). The only long-lasting issue is (I think) the verdana diacrita placement bug, which (if it isn't sorted already - I wouldn't know!) is something we do need to address. -- Finlay McWalter | Talk 15:49, 9 Jun 2004 (UTC)

I agree - I like the new layout after the initial shock - The javascript errors seem to be finally dieing out too! good on you! Erich 19:21, 9 Jun 2004 (UTC)

Yes, I find Monobook to be a lot better too. Great work! --Chopchopwhitey 06:58, 10 Jun 2004 (UTC)

I love the new layout. As I experience it (Mac OS X 10.3.4, Safari) it looks prettier and the text is more legible and the pages are just as information-dense or maybe denser than before. There are very minor glitches—for example, the article creation text tells you to click "edit this page" but the tab, of course, just reads "edit." Dpbsmith 00:06, 10 Jun 2004 (UTC)

I like the new layout too - especially how each user can customize it for themselves. Perhaps we should create a page for Monobook fans? - jredmond 00:17, 10 Jun 2004 (UTC)

In general, I like the new layout, but I still can't agree with overriding the user's default font choices, and forcing a sans-serif font in particular. See also Wikipedia_talk:Serif or sans-serif and MediaWiki_talk:Monobook.css#Font typeface —Steven G. Johnson 06:04, Jun 10, 2004 (UTC)

The new layout is great and professional looking. That way Wikipedia will become mainstream - massa 16:38, 12 Jun 2004 (UTC)

When I first saw MonoBook, I actually went to IRC to ask who made this amazing-looking artistic theme. People who like the standard skin don't value aesthetics! --Menchi 16:40, 13 Jun 2004 (UTC)

Well, in fact they value aesthetics as much as you do, but they feel that bare functionality is more important that glossy looks. — Monedula 10:48, 16 Jun 2004 (UTC)

Sickle cell anemia image

Hi there! I'm doing a bit of work on sickle cell anemia and was hoping that you could provide the copyright status of the image you've placed there. (Since it's from NIH, I'm guessing it's PD, but it's good to double-check :-) Thanks! --Diberri | Talk 18:17, Jun 21, 2004 (UTC)

Yes, automatically public domain as part of a US government publication. AxelBoldt 18:41, 21 Jun 2004 (UTC)

Polymethyl methacrylate

Great work on the PMMA article (IMHO). Thanks!

Well thanks, it has been fun. AxelBoldt 11:49, 26 Jul 2004 (UTC)

Inline TeX

Re: fiber bundle. Please contribute to the LaTeX discussion with your opinions on inline TeX. mat_x 21:29, 8 Aug 2004 (UTC)

Re: Tor functor. I see you have undone some of my TeXifying again. I would like to know why you feel this is a good idea. Best, mat_x 10:43, 17 Aug 2004 (UTC)

Well, it's a matter of taste really; I don't like to inline TeX because the TeX's font size doesn't match the font size of the surrounding HTML, and because it seems a waste to transmit a whole png file where a simple HTML character would do. But if you feel strongly about this, feel free to revert. Cheers, AxelBoldt 11:23, 17 Aug 2004 (UTC)

I think I agree with Ardonik's view of things, which is covered in some detail on the TeX talk page. He claims there that there isn't really a significant difference in the transfer of a .png and HTML; I was initially under the impression that HTML had to be faster. I also agree that the problem seems to lie in the rendering of .pngs inline. However, I'm definitely not savvy on the intricacies of this matter, and as a relative newcomer to Wikipedia I won't be entering into these debates too deeply. I was just checking that you knew what you were doing ;-) mat_x 13:33, 17 Aug 2004 (UTC)

taxobox documetation

Just wanted to give you a head's up: The documentation is in the works. You can see the working copy at Wikipedia:WikiProject_Tree_of_Life/Taxobox_Usage. Feel free to edit at your leisure or discuss on its talk page. - UtherSRG 17:51, 10 Aug 2004 (UTC)

Image without image entry

Hello Axel,

you edited the image description page Image:Kathoey.jpg. This image has no upload information, did you upload it? See also this list for all such images I found. --SirJective 12:45, 12 Aug 2004 (UTC)

Yes I uploaded it. I remember that there was some sort of timeout when I uploaded (the image is very large), so I first assumed it hadn't uploaded properly, but in fact it was all there, only my user information was missing. There's a bug somewhere. AxelBoldt 12:58, 12 Aug 2004 (UTC)

Index set

Hi Axel, I was reading Cartesian product, and I wondered if the cardinality of the Index set needs to be (at most) the same as of the natural numbers, or can it be higher. In none of those articles is explicity stated. Thanks --AstroNomer 00:52, Sep 8, 2004 (UTC)

The cardinality of the index set can be as high as you like, and higher :-) For instance, the set of all functions from R to R is often written as R^R, i.e. a cartesian product of many copies of R, where as index set we take R itself. AxelBoldt 02:09, 8 Sep 2004 (UTC)

LTP

Thanks for your edits to LTP. It's about time someone pored over my original contributions :-) --Diberri | Talk 22:10, Sep 9, 2004 (UTC)

Well, thank you, it's a good article, I learned a lot. AxelBoldt 20:04, 10 Sep 2004 (UTC)

could you take a look at Natural units? it appears that you have made some contribution there. i do have a couple of objections that noted at the talk page. i don't think that the Planck Current is either historically correct nor keeping with the original concept of Planck Units. personally i wish that Planck had normalized 4*pi*G instead of just G, but that is a different (and later) argument.

r b-j (talk page)

Islam & menstruation

Adha does literaly means 'a hurt'! Why did you change the text? Do you understand Arabic? A. 04:42, 12 Sep 2004 (UTC)

I replied on talk:menstrual cycle. AxelBoldt 19:45, 12 Sep 2004 (UTC)

more on Natural Units

could you take a look at my talk page? i posted a more current version of that sci.physics.research article that i called "The Most Natural Physical Units". i really believe that the Planck current is wrong on the Natural units page. but, in addition, more thought should be put into the concept of Natural Units and not simply equate them to Planck Units.

r b-j 18:28, 13 Sep 2004 (UTC)

I think it would be ok to list your concerns about natural current on the Natural units page, especially if Planck never used that notion (but others clearly do, so we shouldn't just delete it). Your other thoughts on natural units make sense to me, but I think they fall into the category of "original research", i.e. ideas that haven't been published and are not (yet) widely accepted, and we try to keep original research out of Wikipedia. AxelBoldt 22:14, 13 Sep 2004 (UTC)

Menstruation picture

Hi. I will do so soon, but currently i am on a trip and away from my regular computer with the neccessary software. I hope to get around to do it next week. I will also include some comments I got when I tried to nominate the image as a featured image, but recalled the nomination. May nominate it again at a later point after fixing it. Cheers -- Chris 73 Talk 21:21, Sep 14, 2004 (UTC)

Thanks, and have fun on your trip. AxelBoldt 22:36, 15 Sep 2004 (UTC)

Trip was highly sucessful. I updated the image based on different online sources (google image search (http://images.google.com/images?sourceid=navclient&ie=UTF-8&q=menstrual+cycle)). The lines match now, and there is a "average only" sentence at the bottom. (Press CTRL-Reload if you still see the old image) -- Chris 73 Talk 13:35, Sep 20, 2004 (UTC)

Very nice, thanks again. AxelBoldt 22:01, 20 Sep 2004 (UTC)

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