User talk:Dan Gluck

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'Bold text'Welcome!

Hello, Dan Gluck, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or place {{helpme}} on your talk page and someone will show up shortly to answer your questions. Again, welcome!  - jak (talk) 16:44, 12 June 2006 (UTC)

How to move a page[edit]

Thanks for moving Picture(string theory) to a more accurate title, but next time it it might be preferable to use the move tag at the top of the page. It takes the history and talk page with it. Cheers - jak (talk) 16:44, 12 June 2006 (UTC) thanks Dan Gluck 17:50, 15 June 2006 (UTC)

Please contribute to Straw Poll[edit]

Hi, we are having a straw poll in order to save the "9/11 Conspiracies" page from generalized disorganization. Could you please help us out by casting your vote [here]? Thanks --146.115.123.152 19:03, 19 September 2006 (UTC)

Secrets of the Baby Whisperer[edit]

Hello,

Thank you for your stub submission. You may wish to note that it is preferable to use a stub template from Wikipedia:WikiProject Stub sorting/Stub types instead of using simply {{stub}}, if you can.

Thanks! --Vox Causa 01:18, 14 December 2006 (UTC)

Proof sketch of Godel's theorem[edit]

I have started a discussion here about this article. Since you are the primary author, I thought it would be appropriate to let you know. CMummert · talk 22:45, 4 April 2007 (UTC)

3D harmonic oscillator[edit]

Hi Dan, in the 3D harmonic oscillator you gave as a factor of the final wavefunction rl+1. IMHO it is rl. I changed it, but could you please check it, so that we agree? Thanks,--P.wormer 11:25, 28 May 2007 (UTC)

Yes, my mistake Dan Gluck 14:09, 12 June 2007 (UTC)


Hi Dani,

You are doing great work here!

Ofer Manela

Hi Ofer what's up? being sarcastic isn't like you at all... Dan Gluck 19:11, 25 June 2007 (UTC)

Hi,

Why sarcastic?
I really meant that.

Ofer

Thanks :-) (Why don't you sign using your username by the way? you do it by writing: ~~~~) Dan Gluck 14:25, 27 June 2007 (UTC)

I don't have a username here, since I don't contribute regularly to Wikipedia. I just edit when I read something and find a mistake.

Ofer

The unfortunate "Fluid Entropy"[edit]

Hallo! You do not need to apologize. I am a little familiar with such situations, because I am active on PL-Wikipedia in rather controversial subject - homeopathy. I did not study physics, I am only interested in the concept of entropy because it explains a lot, even a cancer disease. I wonder, what was told to you about entropy and fluids on the university, maybe you like to tell briefly? I could write about subjects connected with my profession but I prefer new things. I had never thought that "fluid entropy" would be so controversial. I do not know if the article will be deleted or not. I will wait and see. It does not matter any more. Deletion means I am free to do something else, if the article is allowed to stay then I have a lot of work to do in order to improve it and all the critical remarks must be taken into consideration. The discussion is not always nice, but always interesting and useful for all of us, I hope. Greetings. --LidiaFourdraine 16:45, 29 June 2007 (UTC)

Hi Lidia. Well, entropy in general (and fluid entropy as part of it) is a rather complicated subject... this is why I participated in writing the articles about entropy and the arrow of time. Fluid entropy has some special features, but in fact they have general analogues in entropy of other systems. This is basically why I think there is no justification to deal seperately with fluid entropy. Anyway, I invite you to read what is already written in the article about "entropy", I don't think I can easily (or at all) write it better than what's already written there. But if you still have questions, I'll be very happy to try to answer. Have a good day and nice weekend! Dan Gluck 19:06, 29 June 2007 (UTC)
In fact, Lidia, I hope you don't think that you can write about stuff like this after merely reading an article or two in the subject. While this may be the situation in pseudosciences like homepathy, it is not the situation in sciences like physics, where a great body of knowledge has been developed and repeatedly verified to the level that an outsider can have nothing worthy to add. If you do write on physics (and many other subject) without having the expertise needed, you only waste the time of experts in trying to fix what you have done, and instead of benefitting the Wikipedia, you will only damage it. I myself intend to leave physics in favour of Biology as soon as my PhD is over (which is going to happen in October), but as much as I would live to write about the citric acid cycle, I am in no position (yet?) to add anything, and I focus on things which I already know. If you want to benefit the Wikipedia rather than damage it, I advise you to do the same.Dan Gluck 19:54, 29 June 2007 (UTC)

Dan, I noticed that you contacted two other editors, Joshua Davis and PhysPhD, regarding the deletion debate for this article. Please, in the future, do not canvass for votes. It can seriously hinder a good AfD outcome. — Scientizzle 22:13, 11 July 2007 (UTC)

Re. assuming good faith[edit]

Hi Dan- Thanks for the clarification you left on my talk page. It was a misunderstanding that I'm glad has been cleared up. Good thing I won't be pontificating on physics anytime soon ;-) Cheers, — Zerida 00:32, 7 July 2007 (UTC)

Hoax warnings[edit]

Just to let you know: I removed the {{uw-hoax}} warnings that you posted on Calactydacus plant and Bytheria. Those templates are user warnings and they are intended to be used on the user talk pages of the contributors, rather than on the articles in the main wiki. You were correct, however, in adding the {{hoax}} tag. ●DanMSTalk 17:52, 8 July 2007 (UTC)


Hi, i recieved your comment on my article about the water engine and was mildly annoyed. While i respect your view and your education i do not believe that it is right to label the article as a hoax. i would like to hear your views on why it is a hoax as it baffles me why it is, unusual or strange maybe but not a hoax.

Lifeforce99

Aha, i see your point as to why it would appear to be a hoax and i am now unsure of its accuracy. I think i may try to build such a thing to see for myself :D. Thanks Lifeforce99

Invite[edit]

Gregbard 09:59, 14 July 2007 (UTC)

Image[edit]

Regarding your tag on Image:Calabi-Yau.jpeg: the image is nice, but certainly not central to the article. In any event, I am confident it can be recreated by someone with a knowledge of Mathematica. The author even gives instructions on his web page for how to do so. The nonfree image policy does not take into consideration whether it is particularly easy to recreate the image - our policy is that any image that can be replaced with a free alternative should be. I am going through all nonfree images used on math articles to fix their license tags so that they will not get deleted en masse. Some of the nonfree images, like this one, just need to be replaced instead. — Carl (CBM · talk) 13:14, 20 July 2007 (UTC)

OK Dan Gluck 18:54, 20 July 2007 (UTC)

Lorentz group[edit]

Thanks for your contributions to the article Lorentz group. This really is an interesting subject. (Earlier I had some question about your recent contribution - but I found out I made a mistake. )Best regards, Pierreback 15:52, 24 July 2007 (UTC)

Negative Mass[edit]

I am not a physicist by profession, but I have completed a few graduate hours in theoretical physics. I executed an undo command on your deletion of the referenced ZPF phrase because the Breakthrough Propulsion Physics Program had examined the fundamental principles of the diametric drive. Incompatibility between an application of the strong equivalence principle and various attempts to "quantitize" general relativity are notable. The ZPF phrase was not added to strengthen the Standard Model's position. It was added to illustrate other theoretical obstacles it must overcome. Although ZPF may be classified as fringe physics, other theories, such as loop quantum gravity, may share similar incompatibilities. Tcisco 19:42, 31 July 2007 (UTC)

The zero point field (ZPF) had been proposed before the inception of the standard model and string theory. If ZPF is an extension of either, it is by inclusion - it is an application of quantum field theory. ZPF research supported by the NASA Breakthrough Propulsion Physics Program was not couched in terms of the standard model and string theory. The numerous peer reviewed articles, theses, and funded research merit citing it as a specific field instead of lumping it under a broader category. Tcisco 04:36, 8 August 2007 (UTC)

Species integration nominated for deletion[edit]

As someone who has commented on Wikipedia:Articles for deletion/Most ancient common ancestor, you are invited to comment on another article by the same author which I just nominated for deletion. The same author coined a new article Species integration which similar theme with two completely irrelevant references, after the 'most ancient common ancestor' article was deleted. I removed these two irrelevant references, and commented on these on the Talk:Species integration page.

The new nomination/discussion page is at: Wikipedia:Articles for deletion/Species integration.

Thanks. Fred Hsu 01:47, 5 August 2007 (UTC)

Smell fishy to you?[edit]

Doesn't this seem a bit dodgy? OR? Possible COI? PhysPhD 18:14, 9 August 2007 (UTC)

I'm still battle-scarred from the last one of these I took on. If you don't mind, I'd be quite happy to let you have the honors.PhysPhD 22:56, 9 August 2007 (UTC)

Non-critical string theory: Lorentz invariance[edit]

please note that your arguments do not apply, the article:

is not WP:OR, because it is based on the sources, published by several independent authors in reputable journals (Phys.Rev.Lett., Rev.Math.Phys., Int.J.Mod.Phys.)

does not violate WP:NOTE, because there are textbooks on string theory considering the topic (citations added), there is an encyclopedic article on it (reference added), the whole area of activity has an own PACS-number http://www.aip.org/pacs 11.25.Pm Noncritical string theory

BTW, you wrote:

> I checked and all the references I could find in SPIRES-HEP have maximum 8 citings

my SPIRES-HEP search gives more :)

35 citations for F. Rohrlich, Phys.Rev.Lett., V.34, p.842 (1975).

8 citations for G.P. Pron'ko, Rev. Math. Phys., V.2, N.3, p.355 (1991).

13 citations for E.B. Berdnikov, G.G. Nanobashvili, G.P. Pron'ko, Int. J. Mod. Phys. A, V.8, N14, p.2447 (1993); N15, p.2551 (1993).

I have selected these papers as sources due to their complete coverage of the topic. There is a lot more papers on it, please let me know if you want to receive the list.

is not WP:COI: I (string4D) find interesting Lorentz-invariant 4-dimensional quantum string theory and especially its applications in the physics of hadrons. This topic is described in a number of papers, in textbooks, is included into the encyclopedia on the related scope, but it is not even mentioned in Wikipedia. I would like to fill this gap.

you wrote:

> I have no access to the book (reference no. 1)

please follow the link

https://www.novapublishers.com/catalog/product_info.php?products_id=4639

link to the other book also describing the material:

Susan A. Grece (Ed.), New Developments in String Theory Research, Nova Pub. 2005, ISBN 1-59454-488-3 https://www.novapublishers.com/catalog/product_info.php?products_id=3651

link to the encyclopedia: http://www.springer.com/dal/home/physics?SGWID=1-10100-22-173660080-0

String4d 18:09, 10 August 2007 (UTC)

I am not convinced about the notability of the approach you've introduced. Non-critical string theory is of course notable, I'm not talking about that. Dan Gluck 18:48, 10 August 2007 (UTC)
Maybe it's fine to compromise that the page can stay, but no link to it or claims about it will be allowed on the string theory page. However, I certainly get the impression that the page is the attempt of a relatively fringe researcher trying to give their work the appearance of being main stream/notable.PhysPhD 19:24, 10 August 2007 (UTC)

Dan, I took a look and I'm not sure I would label it as OR, since I believe I've seen some papers on the arxiv about this. But the article itself is poorly written and not encyclopedic. Also, it is misleading in the sense that it ignores how the term "non-critical string" is usually used, which is explicitly not Lorentz invariant due to the linear dilaton profile(the statement above that non-critical strings has its own PACS number is also misleading, I think. My impression was that the PACS number is for the non-Lorentz invariant sense of the term not the way that String4d is using it). Notability is kind of a tough call; it is clearly a minor topic within string theory, but so are a number of other subjects which have articles. I'm not sure I would vote that an article on this subject should necessarily be deleted, but the article as it stands is quite bad. My concerns are mostly about the way it was written. I suggest giving the opportunity to clean it up(dramatically). Joshua Davis 22:08, 10 August 2007 (UTC)

I think PhysPhD's solution is the best, at least temporarily. I've added a link to the usual non-critical string in that article. Dan Gluck 10:01, 11 August 2007 (UTC)

Émilie du Châtelet[edit]

I hope I've got this right now. Would you care to look it over? Best. --Old Moonraker 20:58, 12 August 2007 (UTC)

Thanks. --Old Moonraker 10:49, 13 August 2007 (UTC)

FOL edit[edit]

Where in the area of the article that I edited about FOL did it say anything about classical mathematics? Are you having trouble reading the article? I'm too lazy to revert your mistaken "correction". I look forward to more of your edits. Nortexoid 09:29, 24 August 2007 (UTC)

A new search engine for books -- Zercle.com[edit]

Hi Dan,

I would like to invite you and other Wikipedians to check out Zercle.com, which is a search engine for nonfiction books that I've just launched.

Zercle is designed to solve a problem that often plagues us on book sites such as Amazon.com: We spend a huge amount of time trying (and usually failing) to get an idea of what books are available in our particular categories of interest. For example, if you enter "Group Theory" in the search box at Amazon you'll get a hodgepodge of 1431 results, the first page of which is mostly psychology books! It's ridiculous.

What if you want a list of all undergraduate-level books in "Group Theory" that are in-print? Good luck. There's no currently way to get that information, unless you want to spend a few days going through 1431 results. In effect, we're still very much in the Stone Age when it comes to answering such questions.

With Zercle, however, volunteer editors will create, edit and maintain book groups which contain all of the books that are currently in-print in a given category. Zercle has developed a special method for analyzing the core subject of a book to determine which group or groups are appropriate for the book. This is all detailed in the "Instructions for book group editors" page.

Zercle is like Wikipedia in that it is edited by volunteers and thus starts off with very little content being there for users. Unlike Wikipedia, however, Zercle requires editors to register and that they be "knowledgeable enough" in the subject areas that they edit.

I've already started building a few groups on Zercle myself, in the "quantum mechanics" area, since I'm knowledgeable enough there (BS Physics). If you enter "quantum mechanics" into the Title box on the Zercle front page you'll see those groups. If you also enter, say, "Griffiths" into the Author box, you'll see the specific group which contains the QM book written by that author. I've only just started these groups, so none of them are yet complete. But, as I've already alluded, the idea is to eventually have groups that are complete, so that users can easily discover what books are available in their categories of interest, and authors can pretty much be guaranteed that users have an easy way of discovering their book.

Once Zercle gets going we will no longer have to waste countless hours on Amazon only to get a tiny glimpse of what books are available in our particular categories of interest. We'll simply enter the title (or title words and maybe an author's last name) from any book in the category into the Zercle query box, and instantly have at our fingertips a *complete* list of the other books in that category, with links to their corresponding Amazon pages.

Editors are needed in all non-fiction category areas (Zercle does not support *fiction* books). For more info, go to http://www.zercle.com/ and look at the "About" page. For questions/comments: paul at zercle dot com.

Thanks very much for reading this.

Paul White (developer of Zercle)

Emwave 00:05, 28 August 2007 (UTC)

Chirality[edit]

The chirality (physics) page is in need of some help to make precise the distinction with helicity (particle physics), and I'll admit I'm a bit confused. You mind having a look? Thanks.PhysPhD 22:04, 30 August 2007 (UTC)

No problem, within few days. Dan Gluck 20:52, 31 August 2007 (UTC)

Anti-gravity[edit]

Michael Busch has requested a straw poll of Anti-gravity. You may want to comment. Tcisco 00:34, 28 September 2007 (UTC)

Please don't edit/delete other people's posts on talk pages[edit]

Hi. I noticed that you deleted the "cost" section of discussion on the Talk:Mars Climate Orbiter page, "as it is no longer relevant". Although it could be argued that it is no longer relevant, it should not be deleted. I'm not going to give you an official warning, as I am pretty sure you were acting in good faith, but this type of behaviour could be seen by others as vandalism. Please can you refrain from doing so. Thanks --GW_SimulationsUser Page | Talk 20:16, 10 October 2007 (UTC)

No problem. No harm meant.Dan Gluck 18:28, 11 October 2007 (UTC)

Unsolved problems in physics revert[edit]

I don't want to edit war with you on something so silly, but I don't think it was appropriate of you to revert my adding of content to this article, not least because there was not yet a biophysics section in the article. Both problems are strongly within the realm of physics, but as biophysics is often an interdisciplinary field, they have strong crossover with computer science and biology. The literature on both problems is vast, and any progress in either field will be a major breakthrough toward our understanding of the brain and of genetics, respectively, and this breakthrough would come firmly from physics. Therefore, I have reverted your deletion, and I would appreciate, if you have further disputes on this matter, that you would discuss it with me if you still disagree. I think the article should default to having more information, not less, and if you don't believe those are some of the most important questions in biophysics, then I think you should replace them with ones you think are important rather than deleting the biophysics section altogether. SamuelRiv 03:26, 9 November 2007 (UTC)

Tachyon vandalism[edit]

You might want to check out the page. --Michael C. Price talk 00:18, 14 November 2007 (UTC)

Tachyons[edit]

For what it's worth, the reference tag was introduced to indicate that while the references were good, which I don't dispute, they didn't seem to be sufficient for all the statements made. I know from experience that a GA and or FA is generally supposed to have at least two per paragraph. And I stand by the comments I have made on the talk page regarding the article's apparent existing POV and MOS problems, particularly as the Americana source seems to indicate that Feinberg himself at least theoretically holds open the possibility that tachyons could be proven to exist, presumably as particles. I wish that article were longer and more detailed, but it isn't. Regarding the "debates" with Michael, his history has demonstrated a willingness to violate policy and guidelines, including adding sources which in some cases even seem to disagree with his claims, and harrass others in the process. I do not pretend to be an expert on physics, but I've been around enough articles of all kinds, including science articles, to know that we can't just present one opinion exclusively, even if it is the almost unanimous consensus. This doesn't mean that the opposing theories should be given too much space or weight, but they should at least be mentioned. I grant my specific fields are more the "soft sciences", but I did get an astronomy scholarship (among others) in college, and I hope know enough about sciences in general to at least get by without sounding like too much of an idiot. I have no reservations about your own integrity as an editor, and believe that you very likely will work to improve this article, and the others you deal with, in a fair and reasonable way. Regretably, the conduct of at least one other editor involved has been such that it is not reasonable to assume the same about him. John Carter 21:15, 15 November 2007 (UTC)

Only potential disagreement is that the Encyclopedia Americana article was written by Feinberg, and was still published intact as of 1997. If the article is older than that, which I can't know, evidently both he and the publisher thought that the science had not changed enough to merit removing the comment about the possibility of discovering tachyons later. That would seem to my eyes to be at least a form of evidence that, at least as of 1997, there was still some disagreement about the possibility of tachyons existing. If such a source as Feinberg held such beliefs, I believe he is probably notable and reliable enough to make the idea at least mentioned in the article. -- John Carter (talk) 20:19, 16 November 2007 (UTC)

AfD nomination of Particle physics in cosmology[edit]

I have nominated Particle physics in cosmology, an article you created, for deletion. I do not feel that this article satisfies Wikipedia's criteria for inclusion, and have explained why at Wikipedia:Articles for deletion/Particle physics in cosmology. 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. Padillah (talk) 02:53, 28 February 2008 (UTC)

mu problem[edit]

Hi Dan, I noticed the following sentence in your article about the mu problem of the MSSM: "μHuHd (...) is responsible for the fact that both Hu and Hd gets a non-zero vacuum expectation value after electroweak symmetry breaking". As a matter of fact, the mu term does contribute to the mass terms for the two Higgs doublets, but it is not responsible for the fact that they get a vev. The F-term contribution to the Higgs scalar masses originating from the mu term is always positive, and you can very well have EWSB even when mu=0. If mu was much larger than the weak scale you would need a finely tuned cancellation between the contribution from mu and the soft SUSY-breaking mass terms for the Higgses, and this is the nature of the mu problem. But the practical reason why you need mu to be different from zero is the necessity of giving a large enough mass to the supersymmetric partners of the Higgs bosons, i.e. the higgsinos. Do you think that it would be possible to rephrase the sentence to clarify this point? Cheers, Ptrslv72 (talk) 11:15, 3 October 2009 (UTC)

Speedy deletion nomination of File:Woods Saxon potential.gif[edit]

Ambox warning pn.svg

A tag has been placed on File:Woods Saxon potential.gif requesting that it be speedily deleted from Wikipedia. This has been done under section F1 of the criteria for speedy deletion, because the image is an unused redundant copy (all pixels the same or scaled down) of an image in the same file format, which is on Wikipedia (not on Commons), and all inward links have been updated.

If you think that this notice was placed here in error, you may contest the deletion by adding {{hangon}} to the top of the page that has been nominated for deletion (just below the existing speedy deletion or "db" tag), coupled with adding a note on the talk page explaining your position, but be aware that once tagged for speedy deletion, if the page meets the criterion it may be deleted without delay. Please do not remove the speedy deletion tag yourself, but don't hesitate to add information to the page that would render it more in conformance with Wikipedia's policies and guidelines.  Chzz  ►  03:00, 9 October 2009 (UTC)

Can you help?[edit]

The talk page for Godel's incompleteness theorems is being filled with venomous stuff. I recently placed a good version of the proofs of the theorem on the talk page, and now people are arguing that this is somehow bad behavior. If you could say that the material is OK, it would help a lot.Likebox (talk) 21:27, 23 January 2010 (UTC)

It is still going on. There are several editors that really want to get me blocked for putting these proofs there. If you could say "this material is correct and relevant, and should be included" it would help a lot, especially considering that you wrote the page.Likebox (talk) 20:54, 24 January 2010 (UTC)
Well, I wrote the page (the "proof sketch..." page) in its first version, but I'm no expert in the field and someone who is an expert made a new version, which was based on mine but included several points which I overlooked upon. I think there are subtleties to which I am not fully aware, so I'm a bit afraid to make a misjudgement here. Anyway, I'll try to spare time for this during the weekend (which here means Friday and Saturday). I'm not sure I'll have time before that but I promise to try.
PS not that I care (since I trust myself enough:)), but some of your opponents may - it is not considered a faithful policy to ask someone to intervene on your behalf. I once did that and got some people upset for that. So next time you'ld better say something more impartial like "have a look and tell us your opinion" Dan Gluck (talk) 10:33, 26 January 2010 (UTC)
I had a quick look there. Where is your proof that you can construct a program to print its own code? PS your opponents are somewhat right about their original research claim. Dan Gluck (talk) 10:47, 26 January 2010 (UTC)

(deindent) I wasn't asking you to abandon your judgement. The proof that a program can include a subroutine that prints its own code is very simple in any modern programming language. It is presented on Quine (computing), and I gave a sketch. You write a code which includes the statement

OTHER_CODE print_myself(char *R){ Q= "(OTHER_CODE) print_myself(char*R)\n\nQ= ASFADFAFADFADF (REST_OF_CODE)" REST_OF_CODE

Then you print Q into R, taking care to replace the nonsense string ASFADFAFADFADF with the contents of Q surrounded by quotes. There is also the small headache of dealing with code with quote marks, but that is comparatively trivial. Printing your own code is a well known exercise in the computer science curriculum. For languages such as LISP and machine-code, where the code of the program is part of the running program, the exercise is trivial--- you just copy the code into a new region of memory. For languages like C, it requires some thinking.

The question of OR is a judgement call. The proof itself is exactly identical to Kleene's, although the language is more explicit about the computer programs involved, and it is written to be free of recursion theory jargon. So I don't consider this OR, because it isn't original. If you submitted it to a journal, you would get a referee report saying "Kleene did this in the 1940s".

There was a big discussion in mathematics in the 1960s about how to deal with proofs that use computer programs, and the consensus among mathematicians was that computer code should not be allowed in proofs, so that computer science and mathematics will stay separate disciplines. Because of this, the proofs of theorems like Godel's, which are most naturally presented in terms of computer programs, are presented in terms of recursive functions, and this makes them next to impossible to follow.

Anyway, the point of this is to make the proof of the theorem obvious to anyone, including lay-people. The question of OR wasn't really the main issue. The main issue was that the language is not the same as the textbooks, so why should this quirky language be included? I argued that clarity is more important than consistency with the literature, but this was rejected. I believe it's just because I am not a very politically savvy person, and the people there just didn't like me. Also there were people who thought it couldn't possibly be right, because "why doesn't everyone say it like this then?" That's Wikipedia for you.Likebox (talk) 15:57, 26 January 2010 (UTC)

OK, I'll look at it within few days. I also think that clarity is more important than consistency with the literature.
By the way, I have a proof for the missing part in the spin-statistics theorem, which I'll write in the discussion page, but I'm afraid this part is really OR. So I think we'ld better search for another understandable proof somewhere.Dan Gluck (talk) 20:45, 27 January 2010 (UTC)
Honesty compels me to warn you--- if you say anything positive about this proof, you will take a hit.Likebox (talk) 21:40, 27 January 2010 (UTC)

(deindent) If you find Carl's arguments convincing, there's nothing I can do. The argument he gives are that the statements of the form "program X doesn't halt" are not obviously statements about arithmetic. That's true if you are living in 1930, but we now know how computers work, and obviously any statement about the operation of a computer is a statement about arithmetic.

His other argument is that the wording in textbooks is fine, in terms of provability and recursive functions. But as you must know, the proof of Godel's theorem in textbooks is clear as mud. The essential construction is the gloss I gave, but it is inverted so that the sentence you get at the end is central, not the program you write. The difference in clarity is real. Unfortunately, once you understand the program version, and how to translate to the standard version, you start to forget that the standard version was incomprehensible before you understood the program version.

I started editing this page when somebody wrote a talk-page messages saying "let's face it. The lay person will never understand Godel's theorem." And I got annoyed at the arrogance of this. But if I can't get support, I'll give up. I'll leave it on the talk page, wait for the young people to learn it, and for all the old people to go away.Likebox (talk) 02:36, 4 February 2010 (UTC)

Dan--- explicit Godel numbering is a total waste of time. Here's a perfectly fine Godel numbering: ASCII and TeX. Write out any statement of arithmetic in ASCII and TeX, and then it's one long number. It's exactly these time-wasting trivialities that I was sidestepping in the "modern proof". If you want to do this, by all means go ahead, but it can be skippied today.Likebox (talk) 02:44, 4 February 2010 (UTC)
You are write if we take the axioms and symbols to include set theory and/or statement forms. But if they include only Peano's axioms (without induction, which is only taken as a deduction rule), and only the symbols defined in the "proof sketch" article, then the task becomes highly non trivial. Of course the number which you choose for every symbol is not interesting, what is interesting is for example how to construct "p to the power of q" for given p and q by using only these symbols. Dan Gluck (talk) 20:11, 4 February 2010 (UTC)
Yes, I know, but I still think it's a waste of time, even though Godel does this in his article. The main result is that any primitive recursive function can be represented in PA. But PA is too unforgiving to write in. You have to show that PA is equivalent to something sensible to write in, like finite set theory, before you can do the construction simply. It is best to just leave the doability of the construction as a condition in the theorem: you assume that there is some way to translate a statement about a computation into a sentence in the theory (This is "Kleene's T predicate").
Today, this is also much easier to show, because you have simpler Turing complete systems than a Turing machine. The state of a cellular automata is easy to encode as an integer.Likebox (talk) 02:35, 5 February 2010 (UTC)

Dan, you are getting confused on all the points which are sticking points in the Godel-style presentation, but which are not confusing in the computational presentation. Remember, the computational proof is this:

Write the code GODEL which:

  1. Prints its code into R
  2. look for the S-theorem "R does not halt"
  3. halts if it finds it

The program GODEL is an absolute notion: we all know what it means. The form of the code "R" depends on the programming language or machine instruction set, but this is not important at all, and is not the distinction that Carl is making.

The point which Carl is bringing up is that there is a distinction between T being true, and T being a theorem of S. This distinction is only important in step 2, and its the only distinction of this type which is important.

The sentence "GODEL does not halt", when translated into S, is some assertion about numbers. This assertion can be provable or not. If S proves it, it then transpires that GODEL halts, and S proves that too.

This is one of the great benefits of this presentation--- it makes these type of distinctions obvious.Likebox (talk) 10:16, 5 February 2010 (UTC)

Since you are swayed the very unimpressive things that Carl has brought up, it is not necessary for you to help. I will keep it on the talk-page until this generation is replaced, since it is hopeless to try to explain the same point again and again.Likebox (talk) 10:22, 5 February 2010 (UTC)

Spin/Statistics[edit]

Thank you for the prod--- I'm finally getting around to sorting out the Euclidean continuation of chiral spinors and reflection positivity for them too. I worked out the low dimensional cases, but I still am not certain about 8d, and so I am not going to make half-assed comments. The literature on this is horribly confused, most Euclidean theories are only for nonchiral spinors and scalars/vectors.Likebox (talk) 05:21, 24 January 2010 (UTC)

Proofs in articles[edit]

Hi Dan Gluck: your recent addition of a proof to the article on Dedekind finite sets caught my attention. Being a mathematician myself, I'm well acquainted with the desire to add proofs in articles. However, believe it or not, this can detract from the interest of the article for the audience at large of WP. At MOS:MATH#Proofs, there are some guidelines set forth by the math community about inclusion of proofs that I hope you will check out.

In general the advice is "Don't include proofs", unless the proof is about the subject of the article (for example, l'Hopital's rule), or else it illustrates something particularly enlightening about the article topic. The proof at Dedekind finite set is a likely one to be removed, because its relevance is not very direct (it's just to support the correctness of a statement in the article.) A much better way to do that would be to cite the proof in a good text.

At the moment, it is not really a big deal since the article is not very long. That's why I don't really have any immediate plans to carry out such a plan myself. There are just better things to do :) However, in the future I hope you bear this policy in mind, as it might save you some efforts both in authoring and in arguing with other editors about proof inclusions. Happy editing! Rschwieb (talk) 00:06, 16 September 2012 (UTC)

  • OK, no problem. I was not aware of this (relatively new?) policy. I guess in the future I would either make a separate article about a proof (if it seems justified) or emphasize the points which may help the reader to understand the theorem itself (if any); in other cases perhaps a link to proofwiki is the best approach. Dan Gluck (talk) 20:39, 16 September 2012 (UTC)
It looks like the policy was moved there in August 2005 from a separate policy page. Most often we have to invoke it if there are space issues, or if somebody insists on including their own idiosyncratic proof and we need to get rid of it. Rschwieb (talk) 00:33, 17 September 2012 (UTC)