WikiProject Mathematics/Archive8 |
= Articles needing diagrams =
Is there a page listing mathematics articles which are in need of diagrams If not, we should create one somewhere. There are plenty of articles which could be listed. I am handy at doing commutative diagrams and don t mind doing them but I m completely inept when it comes to anything requiring artistic talent. I d like a place where I could put up some requests and handle others. -- 17:02, 2005 Apr 14 (UTC)
:Well, there already is 19:20, Apr 14, 2005 (UTC)
::There are presently no requests in there. Maybe I ll try populating it and see if I get any turnaround. -- 22:04, 2005 Apr 21 (UTC)
::I think a separate page for mathematics-related articles would be a good idea. 22:08, 21 Apr 2005 (UTC)
= like it =
I have noticed a recently created 18:54, 16 Apr 2005 (UTC)
Update: I have done the above. Please use the template when linking to the mathematical genealogy project database entries; also you re welcome to improve the template text. 12:50, 17 Apr 2005 (UTC)
=Plutonium recalculations=
Can someone please redo the calculations involving the half life of Pu on pages 01:55, 17 Apr 2005 (UTC) : Have done this on 12:49, 19 Apr 2005 (UTC)
= Several proposals to modify the List of mathematical topics =
The ). Its only weakness is that quite a lot of math articles are missing from there (in addition to the 3537 articles listed at the moment, there are at least 2000 not listed — and this is a very conservative estimate, the actual number could be as high as 3000 or more).
Now that we have the math categories, and most math articles are categorized, one idea is to add to List of mathematical topics by harvesting the articles listed in the math categories. I would be willing to do that, especially that I already have written some scripts which do most of the work.
One issue would be how to sort the articles, this is discussed at , and seems to be a tractable problem, even if one needs to sort the mathematicians by last name.
That was the first proposal. I wonder what people think. Now, the second proposal. Charles Matthews suggested (see again . So, some feedback on this is also needed.
Now, to the third proposal, closely related to the above. You see, adding lots of new articles will make the lists quite big, and even now some are big (for example, List of mathematical topics (A-C) is 58KB, with almost all contents being links). This causes issues when the server is slow, and when updating with new entries (it happened in the past that the lists actually got corrupted because of that). It can also be hard to check the diffs if lots of changes happen. So, the proposal is to further split the lists, with each letter getting its own article.
Backward compatibility can be ensured by using a template-like thing. If we have the articles List of mathematical topics (A), List of mathematical topics (B), List of mathematical topics (C), one can insert in List of mathematical topics (A-C) the lines:
and the appearance of this list would be as before, and can be also edited as before. The link will still work (I tried these).
So, I wonder what people think of these proposals. Note that they are related, but a decision on one of them need not affect the decision on the other ones. 02:33, 19 Apr 2005 (UTC)
:All the above seems fine to me. 02:57, Apr 19, 2005 (UTC)
:: Having heard no objections, I will proceed. I will also create a 21:40, 21 Apr 2005 (UTC)
:All three proposals sound good to me. The template trick is rather nifty; I had no idea that worked. -- 22:02, 2005 Apr 21 (UTC)
= Scanned math monographs of Polish mathematicians =
Today after following an external link from 21:24, 19 Apr 2005 (UTC)
=Gathering together our conventions=
The new page 11:13, 23 Apr 2005 (UTC)
= Renaming the List of lists of mathematical topics =
There is a discussion at 00:31, 24 Apr 2005 (UTC)
=VfD=
Someone has listed Pearson distribution for deletion:
For some reason this is picking up a few delete votes, and I don t understand why. It s not my field but I know this is a fairly popular distribution nowadays. Any help with cleanup, keep votes, etc, welcome. -- 02:18, 28 Apr 2005 (UTC)
= Things to do section =
I m thinking about adding a Things To Do section to the project page, some thing like:
==Things to do==
Looking for something to do There are several places on Wikipedia where mathematics related requests, suggestions and tasks have been collected together:
Any comments 18:26, Apr 28, 2005 (UTC)
: Sounds fine with me. Some of these links already show up at the bottom of 18:41, 28 Apr 2005 (UTC)
Ok I ve added the above to the project page. 22:03, May 3, 2005 (UTC)
= Template:Calculus -- is that needed =
I just wonder, are things like so useful I put it to the right just for illustration.
:( Note: the template refered to above is now at 02:19, May 10, 2005 (UTC) )
To me, as I followed its evolution, it looks like an ever growing monster of links, popping up in many places. Besides, it is very long and wide, taking up lots of room even on a 19 monitor with high resolution. Also, I thought the category system should take care of linking articles to each other.
I would suggest this template be eliminated, or otherwise be trimmed to the true calculus, which is integrals and derivatives on the real line, no vector calculus, tensor calculus, and what not. Opinions 23:08, 29 Apr 2005 (UTC)
I do not like the template. The scope is too broad and it takes up too much space in the article. So either trim down radically or delete entirely. 10:03, 30 Apr 2005 (UTC)
:My attitude: I have removed it in a number of places. I think it might actually be useful to some readers; but it doesn t need to be on every calculus article. 12:49, 30 Apr 2005 (UTC)
:I agree. It takes up too much space. I think the vector and tensor calculus stuff should go. Perhaps moved to their own templates. 13:23, Apr 30, 2005 (UTC)
I have an idea. We could put Vector Calculus and Tensor Calculus as topics under Topics in Calculus, get rid of all the subtopics that were under those two headings, and then make the overall sidebar narrower. I think that might sufficiently trim it down. 21:25, May 3, 2005 (UTC)
:I ve made a template to show what it would look like the way I suggested. It s located at 22:21, May 3, 2005 (UTC)
:: Looks good, thanks! But I can t promise that at some later moment I won t feel like trimming more the template. :) By the way, what do you think of creating a 22:25, 3 May 2005 (UTC)
::: Hmm... yeah, having a Vector calculus category and a Tensor calculus category would probably help. Should they have sidebars, or just categories 22:46, May 3, 2005 (UTC)
:::: I thought the very purpose of categories is to group similar subjects together. And my own humble opinion is that one does a better job that way than by using templates (sidebars, that is). One day, when I get to it, I will carve out 22:59, 3 May 2005 (UTC)
::::: This is true, but templates do make for somewhat easier navigation between topics within a category. Anyways, unless there s any disagreement, I m going to put the slimmer template in to replace the current one and back the current one up in Calculus2 if it s needed for future reference. 23:10, May 3, 2005 (UTC)
I suggest limiting the use of templates to articles most likely to be read by high-school and college students, and then only on articles that are widely and broadly taught. They have pedagogical value for a student trying to master the material. Thus, the fat template might actually be a lot more useful than the thin template. However, it should be used on only a few pages. 17:02, 14 May 2005 (UTC)
=Now on VfD: Evaluation operator=
The mathematical article 00:39, 10 May 2005 (UTC)
I should have added that I spotted this while listing an another article, namely 08:15, 10 May 2005 (UTC)
:Reminds me of this group: 08:47, 10 May 2005 (UTC)
::The 09:58, 2005 May 10 (UTC)
I listed eucalculus on VfD, after verifying that I could not find a peer-reviewed article about it. The VfD entry is 22:57, 12 May 2005 (UTC)
Discussion on german Wikipedia seems to indicate, that 15:26, 2005 May 13 (UTC)
: Evaluation operator has now been deleted, and the other two articles are listed on VfD; their entries are at 22:24, 17 May 2005 (UTC)
= Major fields of mathemtics =
I ve added an Major fields of Mathematics template to the 13:38, 10 May 2005 (UTC)
: The template in question is at .
: Now, first of all, the style here is not too use that many capitals. That is, one writes Linear algebra instead of Linear Algebra , and In mathematics instead of In Mathematics .
: About the template. I myself do not think it is a good idea. There is already a Areas of mathematics article, having good information.
: I would like to note that the very purpose of categories is to group related subjects together. As such, navigational templates should not be used that much, they just become link farms showing up all over the place.
: This is my own personal thinking, and I am somewhat biased against templates for the reason above. I wonder what others think. 20:36, 10 May 2005 (UTC)
::On this one, I m going to have to agree with Oleg Alexandrov. I like templates personally, but they have to be used with moderation. I just don t think this one is neccessary. 23:23, May 10, 2005 (UTC)
::I agree with Oleg. I am against using a template for this category. Note: I believe that templates are useful and nice in certain pedagogical settings, see debate on the calculus template above. However, a template is inapporpriate for this cat. 17:30, 14 May 2005 (UTC)
To be honest I think that this template shouldn t be neccessary, I had two (good) reasons for creating one. The first is that is is also done in the 00:32, 11 May 2005 (UTC)
: The 00:47, 11 May 2005 (UTC)
: We should probably come to a consensus about whether or not to do this in all categories, but just because someone did it for technology doesn t seem to be a feasible reason to do it for mathematics. I think unless a consensus is reached about the subject, default to whether or not it s neccessary. This one I just don t think is neccessary, especially because there s an article about the major fields. 05:23, May 11, 2005 (UTC)
I agree that mathematics is much richer than it s fields. Therefore the template is biased, but adding more links to it make it lose it s purpose so I suggest the following:
Logic Computer Science Literature Set Theory Signal Processing Journals Arithmetics Digital Signal Processing History Combinatorics Transforms Recreational Mathemtics Number Theory Wavelets Games Algebra ... ... ...
Now you could either put all the categories in the three columns together under 10:52, 11 May 2005 (UTC)
:: (This was written before I saw R.Koot s comment above.) At the moment, we have several ways to navigate through the articles: ::* Wikilinks. This works well, but requires the user to read a lot of text to find the link he is interested in. ::* Categories. They are very useful, but in my opinion not very user-friendly. I actually agree that Category:Mathematics is a bit of a mess; part of the problem is that the list is sorted alphabetically, another part is the lists mixes very different kinds of subcategories, like Cellular Automata (a small subfield), Geometry (a big subfield), Formula needs explanation (a category meant for editors) and Theorems. ::* Lists like list of linear algebra topics. They provide more flexibility (one can sort articles as one wants, introduce subheadings, annotations), but the experience shows that these lists are difficult to maintain. ::* Navigational boxes. Again, I think these can be useful, but they take up space (especially when implemented as sidebars instead of footers) and they tend to grow out of control. :: Unfortunately, none of these is perfect. I believe Charles Matthews has written a whole piece comparing these navigational aids, but I cannot find it anymore. But it would be good to build some sort of consensus on which to use where. -- 11:10, 11 May 2005 (UTC)
:::The point about our existing systems of lists and categories is that they have grown up organically , in line with the articles. They are not an imposed , top-down categorisation. I support strongly the idea of doing it this way. After all, where do top-down lists come from They are basically a bureaucratic idea, and not very compatible with wiki self-organising principles. What we need are a few structures to support the existing system. For example, a guide page outlining the category system, and some project page on which to discuss areas where the coverage remains weak. 08:55, 13 May 2005 (UTC)
::::This is a very good point. 16:44, 14 May 2005 (UTC)
I see that R.Koot went ahead and performed the edits anyway, despite the discussion. I disagree with a number of the edits. About a month ago, 17:46, 14 May 2005 (UTC)
As to the 65 subcategories of mathematics, its certain that this list could be cleaned up a bit and shortened; but I m sure I d shit the proverbial brick if it was not done correctly. 17:46, 14 May 2005 (UTC)
= vote for MarSch s adminization =
Please visit 14:43, 13 May 2005 (UTC)
=Hoaxer is back=
14:08, 14 May 2005 (UTC)
:Is there a way of monitoring what articles are added to (or removed from) a category I m wondering how you discovered the existance of the above page. (No doubt, you re aware of my recent bout of categorization and thus interest in such things.) 17:54, 14 May 2005 (UTC)
::It s possible to monitor added articles, but not removed articles; see 18:26, 14 May 2005 (UTC)
= mathbf or boldsymbol =
Typically, bold font is used for vectors, as in mathbf{x}=(x_1,ldots,x_n). Note that mathbf{xi} does not have the desired effect. I think it would be better to use oldsymbol as in oldsymbol{x}(t)=oldsymbol{f}(t,oldsymbol{xi}(t)) ( 23:52, 15 May 2005 (UTC))
: Well, we ll use whatever works. We can use mathbf, and when it doesn t work, we can use boldsymbol. Observe also that oldsymbol{x} does not show up the same as mathbf{x}, which may be undesirable. 23:49, 15 May 2005 (UTC)
::I didn t know about boldsymbol, but I like it. Use whatever is more appropriate. - 11:43, 16 May 2005 (UTC)
: Vector valued variables should be written bold but not italic so you should use mathbf not oldsymbol -- 00:37, 17 May 2005 (UTC) :: Agree with 01:18, 17 May 2005 (UTC)
= Problem with the what links here feature, affecting the recent changes to list of mathematical topics =
If you check what links to the article Osculating circle, one can see that it linked from the List of mathematical topics (O). However, it does not look as if it is linked from list of mathematical topics (M-O), which is very strange, because if you click on that page you will certainly see the article listed.
On the other hand, if you look at what links to Alan Turing, you will see a link from List of mathematical topics (S-U), which is wrong , as if you visit List of mathematical topics (S-U) you will not see Alan Turing listed there. I removed this article from there a long while ago (since it shows up in list of mathematicians).
As such, the what links here feature does not show links which exist, and does show links which do not exist. This affects the rececent changes from 19:15, 18 May 2005 (UTC)
:I seem to remember that there are some bugs with What links here when combined with templates. I think you should look in the list with wikimedia bugs for details, or wait and hope that somebody gives you a more precise answer. 21:06, 18 May 2005 (UTC)
::I ve been seeing stuff like this in more than Mathematics, but I can t really help you out in knowing what the problem is. It s probably just some kind of bug with the overall feature, as Jitse said. 04:13, 2005 May 19 (UTC)
::: I went to 19:39, 21 May 2005 (UTC)
= Move of Mathematical beauty to Aesthetics in mathematics , comments =
( Discussion moved to 20:00, May 27, 2005 (UTC))
= Covariant, contravariant, etc. =
Here is some discussion from my talk page. -- 14:57, May 20, 2005 (UTC)
wrote:
The entry Contravariant has a notice: This article should be merged into covariant transformation. If you disagree with this request, please discuss it on the article s talk page. I very much disagree. I wrote something on the discussion page but the notice is still there, so here I go.
The term covariant has two very different meanings. In relativity theory (and probably differential geometry) it refers to the invariance of a quantity (generally a measurable one) when coordinates are changed, including changes among relatively moving reference frames. For example, the velocity of light is covariant, and the 13:48, 19 May 2005 (UTC)
[...time passes...]
Dear Anome (sorry to put this as a trailer on some vandalism , but I do not know how to create new messages without appending to old.) I m afraid that the two usages of covariant are so very different that your concept of parallel disambiguation pages won t fly. I have never heard of a contravariant transformation , though you could ask a person more expert than I in differential geometry or differential forms. As I explained, covariant components and contravariant components are two faces, so to speak, of the same thing. The second one, in the case of the differentials of coordinates (hope I restricted my remark to that case) is an integrable quantity, a thing many people do not realise. Thus, if one totals the contravariant component of dx around some closed curve one gets the change in x, a property not generally shared with the covariant component of dx. I do not know how covariant came to be used for vector components, but I do not see it as related to the invariance under transformations. The devil of it is that we can t just change covariant transformation to transformation with invariants for many reasons, including wide usage probably started by Einstein. You could make up a disambiguation page for covariant pointing to covariant transformation on the one hand and covariant tensor components on the other. Unfortunately you cannot just use names like covariant tensor and/or contravariant tensor because these are two faces of one item. So you would have to work with covariant tensor components and make up a page like the existing one for contravariant for that case, so you could change contravariant to contravariant tensor components. Actually, now that I think of it you could rename contravariant as contravariant and covariant tensor components and I d be glad to fill in the covariant portion - you can leave a stub. Then the disambiguation page would fork between covariant transformation and contravariant and covariant tensor components.
:I think we probably need to discuss this at the 14:51, May 20, 2005 (UTC)
::Some confusion here. Differential forms, which are always contravariant, can only replace tensors that are already contravariant and antisymmetric with respect to interchange of indices. The components terminology causes more confusion than anything else in this area, I think. In the presense of a metric you can indeed raise and lower indices , so have the option of taking the components of the variance you want; but that is very much not the basic situation with tensors. 15:14, 20 May 2005 (UTC)
:::When physicists say covariant, they mean tensorial as far as I know. Since tensors exist without reference to any coordinate system they don t transform.
:::This is a fine mess we have here. I think the article about 15:34, 20 May 2005 (UTC)
I am afraid you maths guys are taking the definitions and discussion too far away from what is used by engineers and the more pedestrian of physicists. I have taught relativity using differential forms, but not for a while and had forgotten that part about their always being contravariant. Engineers would be floored by trying to use differential forms and I am not even sure they are useful for elasticity, fluid mechanics in Newtonian theory, birefringent optics, and so on. In all the cases normally used by physicists and engineers, you do have a metric. So the math is getting far afield by discussing cases with and without metric. There are some anomalous theories in physics where the metric is affected by another field (e.g. Brans-Dicke theory and other conformal theories,) and it may be that branes can make the usual usage of a metric muddled (path dependent) but you are getting so far from what can be used in most colleges and in university courses in physics or engineering up through second year graduate school, that I am getting queasy. In relativity, we distinguish general covariance and covariance under the special theory of relativity. In the latter case, measurable quantities have to be invariant to the Lorentz transformation (in the most general sense, including translations and rotations, as well as [constant] velocity differences, but not to time-varying rotation). In the former, the measurables must be locally invariant to change to systems in relative acceleration, including time-varying rotation. While coordinate changes are not measurables in the strictest sense, distances are. By the strictest sense I mean that a reliable measuring tape or clock does not measure a coordinate, but it measures the distance, including the metric. I will stop here or the debate entries will become too long. Anyway, to physicists covariant does not mean tensorial in my opinion, it means invariant to certain coordinate and reference frame changes as I described above. 14:42, 21 May 2005 (UTC)
:I m confused by the confusion. A covariant transformation is the thing that changes the coordinate system on a covariant tensor component on a (mixed) tensor. Ditto for contra. Mass and speed of light are invariant and not covariant. The people who study branes and Brans-Dicke know differential geometry inside-out and upside-down, so I m not worried about them. The above seems to be implying that there is something else out there, not yet documented in WP, that is called a covariant transformation what is that thing 00:19, 22 May 2005 (UTC)
You are absolutely right - sorry - there is no such thing as a covariant or contravariant transformation. If one wants to make up separate names for the operations on covariant and contravariant components, one could use these names, but that would obscure the fact that (when there is a metric) both kinds of components are just different aspects of one thing, the tensor. So I would think that the two items could be combined into one about how to transform tensors, in component form. And also you are right that I should have used invariant for scalars that remain fixed in transformation. I just now referred (way) back to Peter Bergmann s book Introduction to the Theory of Relativity (Prentice-Hall, 1942) and my memory is returning: equations can be covariant under certain kinds of transformation; the transformation is not the covariant thing. When the equation (such as G_{ab} = R_{ab} - {R over 2} g_{ab} + Lambda g_{ab} ) is preserved under coordinate transformations it is covariant. I also agree, and I am glad you agree, that people doing advanced work such as branes and conformal theories do not need any help from Wikipedia; that is why I wanted to steer away from cases where there is no metric, which were referred to by on May 20. So I suppose we need entries for tensors and their transfromation rules, covariant and contravariant components, and covariance of equations - the exact titles are not clear to me. In regards to the previous comment (also by MarSch): :::When physicists say covariant, they mean tensorial as far as I know. Since tensors exist without reference to any coordinate system they don t transform. I agree in part - the tensor is there and we just see different views of it when we take components in different systems, but we need to retain some of what was taught to engineers, physicists and maybe even some differential geometers, who can t easily be weaned from components. I am now probably going to cease writing here because there is, indeed, so much confusion over 03:12, 22 May 2005 (UTC)
:Yes I agree, three articles on essentially one topic is too much. All three, 06:40, 22 May 2005 (UTC)
:Oh, and I do see one point of confusion: the transformation of 06:48, 22 May 2005 (UTC)
I do not see any difference between a tensor and a tensor field, unless the former is a very special case, being defined at only one point, and therefore of little use. I do not consider terms like covariant (for invariance of an equation under special-relativistic transformations) and generally covariant for invariance under more arbitrary transformations in GR (I say more arbitrary because I want to keep the light cones etc preserved) to be out of date. That s what Einstein used so it is worth preserving; otherwise people need to ask the mathematicians who changed the definition what Einstein meant. This kind of thing is often tried by well-intended people who like, nevertheless, to play follow-the-leader. One outstanding case was the late (I believe) Parry Moon of MIT. He wrote the article on illumination in the 1956 Encyclopedia Brittannica, wherein he tried to replace ordinary concepts like brightness, illumination, luminous flux, the lumen etc by a new breed of terms such as pharosage , lamprosity (sounds like something that invaded the Great Lakes, killing many gamefish), blondel, stilb and apostilb. The terms have not stuck very well but can be found here and there. Moon and collaborators (such as Domina Eberle Spencer and Euclid Eberle Moon) wrote many bizarre papers. Early on, Moon and Spencer claimed, in J.Opt.Soc.Am. 43,635(1953), that according to relativity, light from distant galaxies could reach Earth in a few hours or days. This was picked up by young-earth creationists, and stil is, but it is nonsense. More recently, the indomitable trio published items supporting a ballistic theory of light in Physics Essays, and for the latest see this: [http://www.libreriauniversitaria.it/BUS/0521245850/Theory_of_Holors.htm]. So be careful about renaming things like the covariance of an equation. It may be a sign of impending senility. OK, nowadays a janitor is a building engineer and an overweight person is gravitationally challenged, but that s harmless, while to side-track people who want to understand the writings of Einstein, Minkowski, Weyl, Pauli, and many capable if not illustrious successors by requiring them to consult Wikipedia talk pages to find out that the covariance of an equation is now called invariance is uncool. The forgoing was not a filibuster and I am not a filibusterer [http://www.wtblock.com/wtblockjr/spanish.htm]. One final point: Somebody (I believe he was named Kretschmer) once pointed out that you can make anything into a tensor by defining it in one system and transforming it to any other by tensor transformation rules. So, reflecting on that, we see that covariance of a physical quantity or scientific equation means that the same measurement process used to measure it in one system will measure the transformed version of in (transformed using tensor rules) in another system. For example. E^2-B^2 where E is electric field and B magnetic is covariant. E-B is not, but if you measure E-B in one frame and then transform it to other frames by brute force with tensor rules you can claim that it is covariant or invariant etc. So general covariance has more to it - that the physical content is carried over to new frames - not just math. 05:09, 23 May 2005 (UTC)
What I don t like about merging into 22:41, 26 May 2005 (UTC)
:Since this issue is being clouded by various points-of-view, I think we need to talk structure and organisation first. Nouns are better than adjectives, as Laura implies: so we need to treat covariance and contravariance in some central place. I suggest making 09:17, 27 May 2005 (UTC)
= =
Perhaps my fellow math-nerds should look at 04:06, 21 May 2005 (UTC)
: I am sorry about the misunderstanding. What i called BS was your example of a conspiracy of space aliens . I never said that squaring the circle is a topic invented by crackpots . And i got angry because you keep putting words in my mouth which i never said or meant (on three counts including this one). You don t even have to assume good faith, if you just stick with the facts. — 16:30, 2005 May 21 (UTC)
:: I think all of this started with Sebastian putting 17:45, 21 May 2005 (UTC)
I agree with Michael and Oleg in questioning the appropriateness of the category pathological science , for this article. In fact, I think that pathological science is a problematical name for a category. The description given (do people still try to do this).
As to the somewhat unpleasant discussion between Michael and Sebastian, I think there has been some misunderstanding going on. I do not see that Sebastian said or implied that squaring the circle is a topic invented by crackpots rather than a legitimate mathematical problem . Nor do I think he meant to imply that by assigning the article to the category pathological science , although I can see why Michael might have thought so. I think everyone agrees that squaring the circle was a legitimate problem considered by serious and reputable mathematicians, prior to the proof that it is impossible. However, that people nevertheless are still trying to square the circle, is an interesting phenomenon, which is deserving of some thought and discussion, and perhaps even a category. 21:08, May 21, 2005 (UTC)
Yes, I agree. This is exactly what i meant! Thanks for getting back on topic! Possible names include:
01:24, 22 May 2005 (UTC)
:Micheal, I think the request is to come up with a catchy category name that says this topic is a legit topic that tends to attract crackpots ; not just math but in general. 06:56, 22 May 2005 (UTC)
::What exactly is the motivation behind creating a category bringing together subjects attracting crackpots Surely not to attract crackpots more effectively. It seems kind of unencyclopedic to give these things too much attention. 20:51, 27 May 2005 (UTC)
Perhaps 21:19, May 27, 2005 (UTC)
I ll say first of all that it s clear all this resolves around the aggressively named category Pathological science . Let me draw a more modern parallel.
In complexity theory, a classical result is that the class NL (complexity), and indeed the entire log-space hierarchy, collapses to NL — that is, NL is closed under complement. I ve read papers predating this discovery by the most eminent of researchers, still alive today, that claimed that most researchers reasonably believed that the log-space hierarchy did not collapse, and they based some of their results on this. A similar thing happened with the discovery that SL (complexity) is closed under complement, widely believed to be false not so long ago and now trivial as a consequence of L=SL.
The short of it is, very smart and very reasonable people have good reasons to believe that things that are false. Neither they nor the goals they pursue are pathological or even misguided ; rather, they are reasonable actions based on available knowledge.
Finally, one more example: I can t remember the name, but one of the founders of noneuclidean geometry actually believed that Euclid s parallel postulate could be derived from the remaining axioms — in other words, his aim was to disprove the existence of any alternate geometry. He assumed that the axiom was false for purposes of contradiction, going on to write a large book deriving many results from noneuclidean geometry, eventually uncovering a contradiction which was actually an error and proclaiming the theorem proved. Was he a crackpot No. Was his effort pointless Not at all! He didn t achieve the unattainable goal he set, but he discovered a lot of useful things in the process. You don t tell a kid they ll never be an astronaut.
So what s a good category I vote for .
09:44, 28 May 2005 (UTC)
=Possible crackpot pages=
Seems that has unearthed a cluster of physics pages of highly dubious content. I m not sure what to do with them. I d suggest VfD except that I don t quite know that process.
*Coherence condition *Electromagnetic jet *Extended Yukawa potential *Nonlinear Coulomb field *Nonlinear magnetic field *w-field and possibly also *Quantization of the pionic interaction although this last one almost does make sense.
As a whole, these pages seem to be filed with errors, ommisions, indecipherable formulas, a mixture of trite and deep statements, notation pulled from many different areas of physics and mashed together in highly non-standard, incoherent ways. My gut impression is that most of this stuff is dubious original research by an out-of-work Soviet nuclear technician who has a strong grounding in physics, but was unable to master quantum field theory as it is taught today. So what s the WP process for stuff like this 16:39, 22 May 2005 (UTC)
:Linas, I recommend heading over to 17:11, May 22, 2005 (UTC)
These are all created by the same guy - [http://en.wikipedia.org/w/index.phptitle=Special:Contributions&target=Rudchenko Rudchenko] (no user page, so link shows all contributions to date). 17:07, 22 May 2005 (UTC)
: 03:28, May 23, 2005 (UTC)
::Well, it seems they have gone to VfD anyway, which is a process hard to stop once it is started. Rather than theorising about the author, I think it is important to focus on what we know about the content. Which is indeed about an alternate line of field theory, to standard QFT. There is a key passage on one of the pages, which I will cite when I find it. 10:01, 23 May 2005 (UTC) ::Right, the place to begin is certainly 10:08, 23 May 2005 (UTC)
::: Hi Charles, I m the one who VfD ed it. The reason for this is not so much that they re non-standard (you should know by now that I have a weakness for non-standard things), but rather 1) they re pretending to be something they aren t: one could formulate a non-linear electrodynamics, but this isn t what s being done here. 2) They re filled with deductive errors. Sure, the pionic field is pseudo-scalar, (it changes sign under parity), but to argue that this means that the associated (non-relativistic) potential is purely imaginary is bizarre/wrong; the (non-relativistic) Hamiltonian wouldn t be hermitian, which is wrong. I suppose one could try to build up some quantum theory with non-Hermitian pseudo-Hamiltonians, but you d have to lay oodles of groundwork first, and it might not work out in the end. 3) The same formulas show up in gluonic vacuum field and quantization of pionic field . That s wrong. If it had been called pionic vacuum field , that might have flown, but gluons are non-abelian, they belong to the adjoint rep of su(3); they re very different than pions, which would be a singlet of su(3). One musn t write an article about gluon-anything without saying su(3) at least once. 4) Multiple instances of the usage of the non-relativistically covariant Schroedinger equation, followed by remarks such as we can use the Klien-Gordon equation . 5) article on coherence condition : one can t write down a kinetic term that way, at least not without oodles of justification. The coherence condition , a purported variational minimization of the Lagrangian, is missing a few terms. The presentation turns incoherent shortly thereafter; the variation δ s should not be thought of as non-fixed numbers .
::: As far as I m concerned, this stuff is a 14:49, 23 May 2005 (UTC)
::::FWIW, here s why I expound so confidently: my PhD thesis was on the 15:15, 23 May 2005 (UTC)
::One more quickie remark: The standard formulation of a non-linear version of Maxwell s equations is known as 16:51, 23 May 2005 (UTC)
::: The articles are of such low quality they would have to be rewritten anyway. Further, the only person that seems to know anything about it [http://en.wikipedia.org/w/index.phptitle=Special:Contributions&target=Rudchenko Rudchenko] stopped contributing several months ago. And last but not least I could not find any papers on the subjects (except for w-field and nonlinear magnetic field) meaning this will never be verifyalbe. So I m in favor of a delete. -- 12:45, 23 May 2005 (UTC)
:::: Rudchenko is still contributing but is using anon IPs, see: [http://en.wikipedia.org/w/index.phptitle=Special:Contributions&target=194.44.210.6 194.44.210.6], and probably: [http://en.wikipedia.org/w/index.phptitle=Special:Contributions&target=195.184.220.198 195.184.220.198] and [http://en.wikipedia.org/w/index.phptitle=Special:Contributions&target=213.130.21.162 213.130.21.162]. 16:52, May 23, 2005 (UTC)
::::: I m confused. From 195.184.220.198 and 213.130.21.162 he tweaked some formulas, which you wouldn t do if this was a hoax. While he has been creating a link farm and given some very strange replies on talk pages from 194.44.210.6. (If your known similar calculation please give sign here. Rudchenko.) -- 18:27, 23 May 2005 (UTC)
:::::inetnum: 194.44.210.0 - 194.44.210.255 :::::descr: Donetsk Regional General Scientific Library :::::country: UA (Ukraine)
:::::inetnum: 195.184.192.0 - 195.184.223.255 :::::country: UA :::::address: Scientific & Technological Centre FTICOM
:::::inetnum: 213.130.21.0 - 213.130.21.255 :::::descr: Dial-up pools and interface addresses. FARLEP-TELECOM-HOLDING, a subprovider of Farlep-Internet in Donetsk, Ukraine :::::country: UA
:::::: I think it is more likely that these articles are original research than hoaxes. 19:07, May 23, 2005 (UTC)
::: [http://scholar.google.com/scholarnum=100&hl=en&lr=&safe=off&c2coff=1&q=%22extended+yukawa+potential%22&btnG=Search Extended Yukawa Potential], [http://www.shef.ac.uk/physics/teaching/phy304/yukawa.html Yukawa Potential]. Maybe this is of some use to anyone -- 13:04, 23 May 2005 (UTC)
::::Be aware that google and even scholar.google is blissfully unaware of most modern physics and math. Dead-tree media still underpins the dominant publishing paradigm. 16:07, 23 May 2005 (UTC)
= Revert to an old version of manifold =
( Moved to 16:59, 27 May 2005 (UTC) )
=Use of this page=
It is better, I think, if discussions on page content are left on the talk pages of the articles. It is perfectly fine if, in the case of an article of basic importance to mathematicians, an invitation to participate is made on this page. I really don t think long discussion threads on specific content issues are correctly placed here. 10:11, 27 May 2005 (UTC)
: Right. Sorry, I did not think it will go that far. Not again. 15:33, 27 May 2005 (UTC)
I agree with Charles. For obvious reasons, page-specific discussions, usually best occur on that page s talk page. I think there is a tendency to raise page-specific issues here, in order to reach a potentially wider audience, which I must say I do find useful, both as one who wants to reach , as well as be reached. But as Charles implied, that can, to some extent at least, be accomplished by posting a notice (perhaps together with an excerpt of an ongoing discussion) here, with a request that further discussion occur there. In any event, any page-specific discussions which do occur here, should, at some point, be copied or moved to the associated talk page, so as to preserve a more complete historical record there. To that end, unless anyone objects, I will move the above section Move of Mathematical beauty to Aesthetics in mathematics , comments , which I initiated, to 16:32, May 27, 2005 (UTC)
By the way, I also wanted to say that I quite value this project s active and vibrant discussions. The more we do it, the better we should get at it. A project needs a certain critical mass of activity to remain viable. This is a great project and it has a great group of participants, and if it takes an occasional off-topic discussion to keep it active or to assure ourselves that some of us are still alive and kicking, then it is worth it 
(Perhaps, from time to time, we should take attendance!) However, as this page s only archivist, Charles may have mixed feelings about the volume of discussion — so I pledge to help out with that task in the future and also in accord with my earlier comment, I volunteer to go through all of this page s archives, and copy any page-specific discussions to the appropriate talk page. 18:02, May 27, 2005 (UTC)
I think we should create a section on this page to note important discussions: obviously if big edits to 18:07, 27 May 2005 (UTC)
:Should there be a distinct math-related VfD page Are VfD s common in math At any rate, if any come up, I think announces should be posted at least here. 20:34, 27 May 2005 (UTC)
::They are not so common. There have been a few crank pages in the past. Mostly poor material can just be dealt with by redirecting. Also, it is not always clear when topics are technically wrong: who knows enough to be an expert in all branches of mathematics So my policy is not to rush to VfD. Of course sometimes we need it. 14:08, 30 May 2005 (UTC)
= Two math pages set for deletion =
Algebra I has been submitted for deletion, and I did the same thing today for Algebra II. They are about courses with the same name. I think does not look encyclopedic. But either way, here are the links:
00:10, 30 May 2005 (UTC):Might I direct your attention to 00:27, 30 May 2005 (UTC)
::This article is part of a collection of articles, which are all part of a class project. They are being discussed here: 01:45, May 30, 2005 (UTC)
:::Thanks, I missed that. Very strange though... -- 11:40, 30 May 2005 (UTC)
= Vfd for space mixing theory =
The page on 10:39, May 30, 2005 (UTC)|
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