User talk:Jheald

Welcome and Software patent

Hello and welcome! Thanks for your contribution in the software patent article. I have added two comments within the text which read: "Please cite your sources" (visible only when editing). It would be nice to integrate authoritative sources to support the matter you added (particularly after the FOLDOC definition and regarding the definitions according to taste of "pure software patent"). See also No original research. --Edcolins 12:04, Nov 30, 2004 (UTC)

Thanks for adding the sources in the article Software patent. But what do you exactly mean by "EP article 2(ba)" and "EP article 2(a)"? --Edcolins 07:31, Dec 12, 2004 (UTC)

The references are to the amendments passed to the software patent directive by the European Parliament in September 2003, see eg http://www.ffii.org.uk/swpat/eudir/texts/articles.html . Note that in most cases for readability I am summarising; quoting phrases directly only where indicated.

Moving

Hello, if you want to move a page could you please use the "move" function (in the topbar), instead of copying and pasting from one page to the other, because this loses the edit history, thanks. G-Man 22:26, 6 Jan 2005 (UTC)

I did (??). But double-redirects I think have to be edited by hand.

Patentable subject-matter

If you don't mind, I moved the whole discussion to Talk:Patentability so that everyone can join in. --Edcolins 20:43, 17 October 2005 (UTC)

Math notation

Hello. Please don't use "<" and ">" for angle brackets in TeX. Observe:

Orthonormal functions are normalized such that

$\langle f_{i},\,f_{j}\rangle =\,\delta _{i,j}$

with respect to some inner product <f, g>.

(See my follow-up edits after your edits to normalizing constant.) Michael Hardy 20:15, 28 October 2005 (UTC)

Thanks. (I'm still on a learning curve here).

Thank you and remark

Thank you for your additions to catastrophe theory. And one remark. Using the edit summary and minor edit button a bit more often does not hurt. :)

By the way, you may be interested in Wikipedia:WikiProject Mathematics and its talk page. That's where a lot of discussion takes place. Oleg Alexandrov (talk) 04:23, 18 November 2005 (UTC)

Mediator response

The edits on Creationism should be put in other places. Mainly this is on physics topics and there are a lot of other possibilities to create new articles on Creationism and relationship with/or/and second law of thermodynamics. I am waiting your response.

• I suggest you create new articles for Creationism and relationship with/or/and second law of thermodynamics and let the article of second law of thermodynamics free of ambiguous links. -- Bonaparte talk 13:11, 28 December 2005 (UTC)

Second Law of thermodynamics

Hello - could you take a look at the edits by Flying Jazz on the second law of thermodynamics page? They relate to our discussion on availiable energy on the talk:entropy page, concerning the energy availaible for work. Among other things, I don't like the "fluxion" notation FJ is using, but thats only because its not standard. It is in fact more informative. Thanks - PAR 19:35, 4 January 2006 (UTC)

Hi! In general, I have a sense that the thermo in wikipedia is great but open systems seem under-represented even though in some cases they're simpler to deal with mathematically than closed ones and more applicable to real-world power generation too. I'm not sure yet about your changes to the second law content I added, but I know I like the R subscripts better than I had there. Could you also look at the changes I made on the enthalpy page? Thanks! Flying Jazz 08:12, 10 January 2006 (UTC)

Hi - more of the same. Could you check out recent edits to Free energy - I still don't have a intuitive sense of this free energy stuff except mathematically. Thanks - PAR 02:20, 30 January 2006 (UTC)

Phoenix

After there are no (non-talk page) links pointing there, would you support a changing of the redirect to Phoenix, Arizona? Leave a note on my talk page, please. Matt Yeager 00:00, 27 January 2006 (UTC)

Catastrophe theory

Great work!! Very nice and informative article. deeptrivia (talk) 21:01, 2 February 2006 (UTC)

Matt Yeager

Hi, you may be interested in reading the comments at Wikipedia:Requests for adminship/Matt Yeager. Austrian 20:54, 3 February 2006 (UTC)

Software patents under the European Patent Convention

Thanks for your message on the talk page of this article. Your suggestion does not seem to have been heard. Instead, I received nice compliments from User:80.237.152.53. I will not revert it back but I am confident that a reasonable solution can be found... --Edcolins 08:20, 15 February 2006 (UTC)

{category redirect} description?

Hi. I saw your comment on the feb 12 2006 CFD page regarding {{category redirect}}'s instructions. Currently the talk page for that template does say:

• Q: Why doesn't the bot operate on my category?

A: Any category using this template now requires the last edit of the category to be made by an administrator.

I think that the instructions for cat redirects in general could be made clearer though, so I may try to take a look into improving it. As an admin, I didn't even know thats how one flagged the category for moving for several days after I started at cfd. :/ --Syrthiss 14:13, 20 February 2006 (UTC)

Yep, thats what I was thinking too. That is indeed the preferred behavior, IMO. --Syrthiss 14:26, 20 February 2006 (UTC)

Clan Fraser

Hi. Thank you for taking an interest in the Clan Fraser article. There are many theories as to how the Frasers came to Scotland, but your Norman theory is only one. I find it POV to label all the greater Clan as Scoto-Norman. If you wish to create an article for either Clan Fraser of Philorth (now Saltoun), feel free to label them Scoto-Norman. However, the Lovats, and the Family, are not Scoto-Norman. We are a Scottish Highland Gaelic Clan, and have been so since the 13th century or so. I'll be removing the label from Clan Fraser, and especially from Clan Fraser of Lovat. I will however, add mention of the Norman theory.

Haplogroup R1a (Y-DNA)

Hi there Jheald. Why did you change R1a to R1a1 in Haplogroup R1a (Y-DNA)?

I'm not a geneticist, but AFAIK, R1a1 is only one subgroup of R1a, associated with the change M17. There is also the branch R1a*, without the M17 change. See this chart. --Saforrest 08:22, 27 February 2006 (UTC)

Hi there. I had a look at the Anatolia paper; I couldn't find any mention of M17 on the first couple of pages, but both Figure 2 and Table 2 associate M17 with R1a1 specifically. They don't even mention R1a or any other R1a group other than R1a1; they're probably not significant for this study.

On the other hand, the National Geographic Genographic Project openly equates M17 with R1a, but that's a bit fishy since they also equate M173 with R (when M173 is actually R1).

Now, it certainly appears that R1a1 is overwhelming more abundant everywhere (not just in Europe) than any other R1a haplogroup. I agree with your point: if almost every car on the road is a Ford Taurus, we should say so and not just call them all Fords.

With that in mind, I propose moving the page Haplogroup R1a (Y-DNA) to Haplogroup R1a1 (Y-DNA). R1a* can be mentioned there on in the page Haplogroup R (Y-DNA), which can serve as survey of all the R subgroups, including tiny ones. Sound reasonable? --Saforrest 17:36, 27 February 2006 (UTC)

Entropy history section

Jheald, in the entropy history section you changed John von Neumann’s quotes around; in a sense, putting words in his mouth that he did not say. I would appreciate it if you would go back and replace the original quotes. Editing is one thing; changing history is another. Thanks: --Sadi Carnot 04:59, 10 April 2006 (UTC)

Version according to (Jheald):

Claude Shannon introduced the very general concept of information entropy, used in information theory, in 1948. Initially it seems that Shannon was not particularly aware of the close similarity between his new quantity and the earlier work in thermodynamics; but the mathematician John von Neumann certainly was. "You should call it entropy, for two reasons," von Neumann told him. "In the first place your uncertainty function has been used in statistical mechanics under that name, so it already has a name. In the second place, and more important, nobody knows what entropy really is, so in a debate you will always have the advantage."

Version according to (John Avery):

An analog to thermodynamic entropy is information entropy. In 1948, while working at Bell Telephone Laboratories electrical engineer Claude Shannon set out to mathematically quantify the statistical nature of “lost information” in phone-line signals. To do this, Shannon developed the very general concept of information entropy, a fundamental cornerstone of information theory. Initially it seems that Shannon was not particularly aware of the close similarity between his new quantity and earlier work in thermodynamics. In 1949, however, when Shannon had been working on his equations for some time, he happened to visit the mathematician John von Neumann, who asked him how he was getting on with his theory of missing information. Shannon replied that the theory was in excellent shape, except that he needed a good name for “missing information”. “Why don’t you call it entropy”, von Neumann suggested. “In the first place, a mathematical development very much like yours already exists in Boltzmann’s statistical mechanics, and in the second place, no one understands entropy very well, so in any discussion you will be in a position of advantage.”^[1]

Reference

1. ^ Avery, John (2003). Information Theory and Evolution. World Scientific. ISBN 9812384006.

Does this revised version sound better? I've cleaned it up a bit; it is sourced by Nobel Prize winning author John Avery, in what is essentially a small textbook on information theory. The chapter in which the above paragraph is copied, word-for-word, contains seven sources by Shannon, from the years '48 to '93. I hardly think that a famous 1949 story by the "father of information theory", only recently appeared in 1971, 22-years after its inception? Either we can work together to make compromise, or we can put both our versions on the entropy talk page to see what other editors think.--Sadi Carnot 16:04, 10 April 2006 (UTC)

Moved discussion to talk:entropy; I think we should let this debate sit there for a while to see if anyone else has an opinion?--Sadi Carnot 17:21, 10 April 2006 (UTC)

I started the page History of entropy and move our discussion there. I tried to incorporate both of our views into the section. I hope it will be agreeable to you?--Sadi Carnot 01:03, 11 April 2006 (UTC)

Frequency probability

I note that you are one of many users who's had a problem with User:INic at Frequency probability. S/he routinely censors any discussion of Bayesian alternatives to frequentism. I've had a series of reverts on an attempt to include a single sentence. I thought I might tag you in, if you're interested.

Entropy

Jhead, what are you doing? You just reverted all of my work to the intro? see: Talk:entropy. --Sadi Carnot 04:39, 20 June 2006 (UTC)

haplogroup R

hold your horses, please. There can always be an independent R1a1 article per WP:SS, but I'm working on building a coherent central article here, don't demolish that. The article was nowhere near unwieldyness, it was just approaching 'substantiality'. dab (ᛏ) 21:27, 28 June 2006 (UTC)

Risk

Heh, good catch -- I forgot the big one! --Dhartung | Talk 20:31, 11 July 2006 (UTC)

Thank-you for the Kelvin link

Wisconsin University have a scan of the paper online here. Thomson, William, "Kinetic theory of the dissipation of energy", Nature, IX. pp 441-444 (April 9, 1874). It can also be found reprinted in Harvey S. Leff, Andrew F. Rex, editors. Maxwell's Demon 2: entropy, classical and quantum information, computing: 2nd edition. Institute of Physics. 2003 -- Jheald 07:47, 12 July 2006 (UTC)

Thank you very much Jheald. These old papers and books are very hard to get a hold of. If interested, here's a link to a partial selection of some of his other papers. The guy who types these papers up and puts them on line is Lyle Zapato, he's a big Kelvin fan, who lives in France. Thanks again: --Sadi Carnot 11:43, 12 July 2006 (UTC)

I think you may have been misinformed by agents of the Belgian Conspiracy. I do not live in France; I live in the Republic of Cascadia. Lyle zapato 09:26, 9 October 2006 (UTC)

Barnstar

		The E=MC² Barnstar
		For your work in theormodynamics and statistical mechanics. Blnguyen | rant-line 04:56, 2 August 2006 (UTC)

Micro black hole / Black hole electron

Jheald; Your edit of "Micro black hole" was very well done. The article has definitely been improved. I would like to encourage you to edit "Black hole electron" also. The article could show that the Bh concept may explain an electron property that is not explained in any other way.

The point particle problem, where we think of photons being created and absorbed at mathematical points and the infinite density of charge implied by point electron pariicles and point interactions is explainable when the electron is defined as a black hole. The density of a black hole is very high but not infinite. With gravitational collapse, the resulting size will approach the gravitational radius. To a first approximation this is zero radius with infinite density. Black hole density is explainable, infinite density is not. DonJStevens 16:00, 5 August 2006 (UTC)

Marginalization

Hi, I have been trying to improve this article, so please take a fresh look at it and see how we might improve this important article further. many thanks Peter morrell 16:04, 9 September 2006 (UTC)

Black hole electron question

Hi Jheald; I added the equation below under "Talk black hole electron". The L2 length is defined as 1/2 of the electron Compton wavelength or 1.2131551x10 exponent-12 meters.

(L2) squared = (L3)(2pi)(Planck length)(3/2)exponent 1/2

When this equation is solved for L3, the value obtained is 1.1834933x10 exp 10 meters (using 1.616x10 exp-35 meters as the Planck length value). If the L3 true value is slightly larger or 1.1835332x10 exp 10 meters then the L3 length is (2pi) squared times one light second. Note that 1.1834933/1.1835332 is 0.9999663.

I would like to describe the (L2) squared equation as a "self-evident truth" indicating that "L3 is (2pi) squared times one light second" because this can be easily verified to 4 significant digits by anyone who is interested. Do you think this is too speculative for Wikipedia? DonJStevens 15:57, 21 September 2006 (UTC)

When (if) we accept the value 6.6717456x10 exp-11 as the actual G value that applies at the subatomic particle level, then equations defining electron quantized mass and time dilation (gravitational potential) at the electron black hole radius (3G m/c squared) become simplistic. Evidence relating to this is described at my "User" page. DonJStevens 15:23, 24 September 2006 (UTC)

You may find the simplistic equation for the electron Schwarzschild radius is interesting.

radius = (2/3)(Le/4pi)(Le/2L3)squared

The Le value is the electron Compton wavelength. This radius value is 1.3524368x10 exp-57 meters. This will be numerically equal to (2Gm/c squared) only if G has the specific value implied earlier (6.6717456x10 exp-11). DonJStevens 17:23, 30 September 2006 (UTC)

The other important electron black hole radius is 3Gm/c squared.

3Gm/c squared = (Le/4pi)(Le/2L3)squared

m = (c squared/3G)(Le/4pi)(Le/2L3)squared

The value (h/c)(1/Le) is then substituted for m.

(h/c)(1/Le) = (c squared/3G)(Le/4pi)(Le/2L3)squared

This equation is then solved for Le.

Le = 4pi(3pi hG/c) exponent 1/4

Do you see any way to clarify these equations so that readers will know that Le is a length value? Your comment on this would be appreciated. DonJStevens 17:35, 9 October 2006 (UTC)

Emergency!

First, I would like to thank you for your courteous response to my (unfortunately normal) overly emotional reaction to information theory (NOT to you as an individual!). Recently, I had been writing only about mixtures because that had been the focus of the last month. Energy dispersal, of course, applies directly and obviously to thermal transfer of all sorts. (And space is involved but an ignorable part of the calculation of entropy change compared to the q/T)

However, my writing you at the moment is truly an emergency -- Sadi Carnot, aka Libb Thims (sic and sick!) at http://www.humanthermodynamics.com/Libb-Thims.html has just deleted all of our discussions of the past month from the Talk:Entropy page. I do not know what to do, not being skillful in Wikipedia high=level procedures. I have sent "Thims" an email requesting clarification of his two degrees in engineering (that my ex-student, a prof in engineering at the U. of Mich could not verify) and his enrollment in a non-existent "University of Berkeley". (The University of Califonia at Berkeley has never been called that.) His major non-Wk writing appears to deal with human interactions and thjermodynamics; I hardly feel that "the thermodynamics of sex" is a legitimate area for thermo, but "Carnot" does!

Can you appeal to authorities? This kind of disaster, in my view, is what I think is vandalism to Wikipedia system -- but what can one do? Frank Lambert: email at [email protected]. I would appreciate aid in any way .FrankLambert 16:22, 6 October 2006 (UTC)

Information theory references

Hello - Do you have any references on the relationship of information entropy and thermodynamic entropy? Email or talk page, either is fine, thanks for any help. PAR 18:53, 19 November 2006 (UTC)

New Thermo Template

Hello - could you look at the discussion page for the thermodynamics template? (HERE) - thanks PAR 06:49, 29 November 2006 (UTC)

Ideal Gas

Hi - could you check out Talk:Ideal gas#nR is amount of gas and give your opinion? Thanks PAR 14:59, 11 December 2006 (UTC)

Directive harmonizing the term of protection ...

Hi, you nominated Directive harmonizing the term of protection of copyright and certain related rights for a history merge, to make place for a move. Is there consensus for that move? I'm inclined to simply delete the target page without a histmerge, as there seem to have been no substantial, non-trivial edits on that page. I'll recreate it as a clean redirect which you can override by a move if you need. Let me know if you need the history back after all. Fut.Perf. ☼ 18:44, 26 January 2007 (UTC)

"Boltzmann's equation"

Changed Boltzmann's equation to point to Boltzmann equation, not Boltzmann's entropy formula. Anything else would be madness. Jheald 17:45, 5 February 2007 (UTC)

Yes, this sounds reasonable. Also, would you mind commenting here: Template talk:Thermodynamics timeline context. Thanks: --Sadi Carnot 18:44, 5 February 2007 (UTC

Kullback–Leibler divergence

Hi! Please see my comments on the talk page.... Cheers... MisterSheik 14:03, 3 March 2007 (UTC) Hi! Please see my response on my talk page.... Cheers... --MisterSheik 16:12, 4 March 2007 (UTC)

By the way, I want to add that I think that we're moving in the right direction and that the information entropy article has become much more readable in the last few days... So, thanks for the helpful edits! :) MisterSheik 16:15, 4 March 2007 (UTC)

Reply to CFD comment

I was too busy to check replies to my comments on that category discussion. So, let me reply here for the record (the cfd discussion is closed).

You wrote:

" "Using thermodynamics you cannot calculate the entropy" ???? I take it you have never taken a course on statistical thermodynamics, or even a basic course on solid-state physics, or you would have to calculate at the very least the heat capacity of the Einstein model of a solid, and its enhancement the Debye model? Nor ever used it to calculate the elastic properties of polymers (see eg loop entropy)? Calculating entropy and related quantities from formulas like the Gibbs entropy and the von Neumann entropy is an absolutely everyday occurrence, fundamental for understanding phase transitions, and a whole host of physical properties. "

I teach statistical mechanics at university and do research on exactly solvable models in 2d using Yang Baxter equations, Bethe Ansatz etc. So, I know what I'm talking about. You should have realized that I use the word "thermodynamics" in a more restrictive sense that you do. Also, "thermodynamics" is actually a misnomer, it should be called "thermostatistics", as pointed out by F. Reif in his textbook.

I agree with the points you made here:

" "most people who know what it means will think of entropy as discussed in the physics articles". I wonder if that is actually true or not. There are a lot of people who work with information who constantly use Shannon entropy, and never have to think of thermodynamic entropy at all - people working in data compression, signal processing, electrical engineering, statistical modelling, machine learning... I wonder if there may not actually be more of them than of people working with thermodynamic entropy. There would certainly be little sense in making the entropy in data compression a sub-category of thermodynamic entropy. But there are enough people that think like you, that thermodynamic entropy is "the" entropy, that that is why I originally thought to call the category "entropy in thermodynamics", rather than "thermodynamic entropy". I'm still myself not 100% sure as to which of those two namings is better. But both are more accurate than the category the overarching name "entropy", and then only putting thermodynamics articles there. No: the split into two sub-categories makes sense, and so does coming up with the right identifying names for those categories. Jheald 21:18, 10 March 2007 (UTC)"

Count Iblis 14:43, 17 March 2007 (UTC)

Equipartition theorem better now?

Hi Jheald,

Thanks for your great suggestions on the equipartition theorem; I tried to revamp the article so as to give a more qualitative description in the lead. Does it seem OK to you now? Any suggestions for further improvement would be most welcome! :) Willow 16:36, 30 March 2007 (UTC)

Hey, if you have time, could you please look over Encyclopædia Britannica and make suggestions for improving it? It's a Featured Article candidate now. Thanks! :) Willow 22:54, 30 March 2007 (UTC)

Hi, equipartition theorem has been improved still further; would you have a chance to look it over and make suggestions? Thank you, Jheald! :) Willow 13:17, 17 April 2007 (UTC)

Hypercomplex

Hello - thanks for going over several articles relating to hypercomplex numbers and adding content. I've begun some follow-up editing, and worked for starters on the multicomplex number article. I have a question about the use of direct sum vs outer product: You're using both, but I'm not entirely clear what the advantage for using one over the other would be in this case, if any. Comment appreciated: Talk:Multicomplex number Thanks, Jens Koeplinger 12:22, 1 April 2007 (UTC)

Black hole electron

Hi Jheald. Much more has been added to "Talk:Black hole electron"; thru item 9 Quantum-gravitational effect. I would very much like to know if you see anything there that you would disagree with. Many years ago Dirac said we have one too many constants in the quantum equations. He expected that we could, at some future time, derive the Planck constant. I want to add information relating to a derivation of this constant. Please let me know what you think of this. [[DonJStevens 16:38, 4 April 2007 (UTC)]]

List of venture capital firms

Hello!

You defended this page about 9 months ago. Just you know, I've remarked this for deletion. Please do not hesitate to revert me if you still feel it is worth saving.

Regards, --Abu-Fool Danyal ibn Amir al-Makhiri 17:12, 5 April 2007 (UTC)

thank you for your recognition

Hello, have I accidentally touched a raw nerve because you are very committed to Scholarpedia project? In the math project discussion page you commented on my staggering lack of knowledge and called the observation that their 'exhaustive coverage of a few narrow fields' (in present tense in the original) is largely empty facile. I am sure that you can back up your mighty talk with excellent academic credentials, because otherwise you would appear like an obsequious youth. Still, I would appreciate it if you retract your personal insults, and keep to constructive critique. Perhaps, you can compute the fraction of the articles that have already been written, and the average time it has taken (I had actually had gone through quite a few more than I indicated, and also noticed a few other peculiar things, although it hardly seemed prudent to post an exhaustive list in order to make my point). Sincerely, Arcfrk 01:12, 17 April 2007 (UTC)

Thank you for changing the tone of your comments. I think we both agree that Scholarpedia is not (yet) fully operational, but holds promise for the future. If you care to take a look, you might also agree that their coverage of Differential Equations is not on par with (current or projected) coverage of Ergodic Theory or Dynamical systems. Best, Arcfrk 22:45, 18 April 2007 (UTC)

Equipartition

Hi Jheald,

Would you have a moment to look over equipartition theorem again? I think it's improved a lot over the past week. Thanks muchly! :) Willow 22:37, 18 April 2007 (UTC)

Mean information

Sorry, I did not observe the hint to "average information content" in the article information entropy. Nevertheless, I think the phrase "mean information" is less clumsy and in analogy to "mean fitness" used in biology. Therefore there is no need for any article about mean information, but a look up word refering to "average information content" in information entropy would perhaps be good, because I have made some references to mean information, which must otherwise be taken away.--Kjells 07:19, 19 April 2007 (UTC)

possible answer

At talk:Good-Turing frequency estimation, you wrote:

According to the article:

The first step in the calculation is to find an estimate of the total probability of unseen objects. This estimate is $p_{0}=N_{1}/N$

The next step is to find an estimate of probability for objects which were seen r times, this estimate is $p_{r}={\frac {(r+1)S(N_{r+1})}{NS(N_{r})}}$

Where do these estimates come from? What prior probabilities are being assumed? -- Jheald 10:13, 4 March 2007 (UTC)

You might find the answer at empirical Bayes method. Michael Hardy 23:18, 4 May 2007 (UTC)

Spinors

Hi jheald,

I don't quite understand how you are using ideals in the Clifford algebra to isolate the column vectors. (For one thing, the Clifford algebra — or the part that matters anyway — doesn't have any two-sided ideals.) Anyway, that doesn't seem to me to be the way the Clifford algebra approach is normally viewed (in such explicit terms): the representations "exist" because the Clifford algebra is isomorphic to a complete matrix algebra. (Usually by some sort of complicated algebraic trickery.) Once you have this isomorphism, then you can start to talk about spinors in Δ (or, in even dimensions, Δ₊ and Δ_-) which are the column vectors on which the matrices act (the matrices, at any rate, purported to exist by this isomorphism). So, using ideals to isolate the column vectors is unnecessary: we already have the column vectors (in Δ, etc). In fact, these column vectors form the irreducible representation (no further reductions can occur). I do feel that an explicit description of the spinors is necessary, since the whole apparatus of Clifford algebras, while extremely useful for determining everything there is to know about spinors, has always left me with an odd feeling of something undone: So... what's a spinor anyway? Call me a Platonist.

Anyway, I don't think you're going to have much luck getting at the spinors through any sort of construction using the Clifford algebra, unless you're willing to accept what I say at face value: that there is such-and-so isomorphism. Some time back, someone had pointed out that there is no "physical" way to isolate the space of spinors. Thus to pin down what a spinor actually is, one is forced to look outside any algebraic constructions happening on the Clifford algebra. The "Explicit construction" is precisely such a gadget. Moreover, the lack of physicality is clear in this construction: it depends on an initial choice of isotropic space.

So don't try to make the Clifford nonsense satisfying in a Platonistic sense. It isn't supposed to. It's a complete and absolute kludge, albeit a very useful one. Silly rabbit 01:43, 5 May 2007 (UTC)

Ok, I see what you're doing. That's interesting. It has to work, but I don't see a way to get to the isotropic subspaces. Do we know, for instance, that (vf)² = 0? (Here v ∈ V and f is your projection operator — acting on the right, somehow I missed that before.) Silly rabbit 02:03, 5 May 2007 (UTC)

Alright, so I think a much cleaner way to go the route you're attempting is to say something along the lines of "The space of spinors Δ can be identified with a maximal anticommutative graded subalgebra of the Clifford algebra." That's actually a nice way to look at it. Of course, in even dimensions this decomposes into the even and odd parts. By your leave, I'd like to restore the original Clifford algebras section, and bring this in to the lead paragraph of the Explicit construction section. Silly rabbit 11:53, 5 May 2007 (UTC)

Thank you for the very detailed response on my talk page. I think I more fully appreciate what you are trying to do, but somehow it still needs to be fleshed out a bit better. You mentioned one case where the idempotent has a geometrical significance: A Lorentz boost up the null cone. This sounds promising. Let's both think about it. Silly rabbit 23:26, 5 May 2007 (UTC)

I don't see how to generalize the 1+e₀ directly. This doesn't even seem to have the correct rank to generate the spinor space as a left ideal (it's imprimitive). Here's another approach.

Another way to get at the spinors without relying on a fixed matrix representation is to consider nilpotent elements. In the language of the Detailed construction section, we can consider the tensor products

${\begin{bmatrix}0&1\\0&0\end{bmatrix}}\otimes \dots \otimes {\begin{bmatrix}0&1\\0&0\end{bmatrix}}.$

Any of these factors can be replaced by a copy of ${\begin{bmatrix}0&0\\1&0\end{bmatrix}}$, producing another nilpotent matrix. The left ideals generated by each of these matrices are isomorphic to a space of spinors. This can be formalized without referring to the matrices by choosing a basis v_i, w_i of V ⊗ C subject to the anticommutation relations

v_iv_j = -v_jv_i

w_i w_j = -w_jw_i

v_iw_j = -w_jv_i (i≠ j)

v_iw_i + w_iv_i= 1

In terms of an orthonormal basis of V, we can write

$v_{j}={\frac {e_{j}+ie_{j+k}}{2}},w_{j}={\frac {e_{j}-ie_{j+k}}{2}}.$

We can then form k-fold products of these, such as v₁v₂w₃... in 2^k different ways. (Thinking of these as matrices, each choice of v and w in a factor is the same as a choice of ${\begin{bmatrix}0&0\\1&0\end{bmatrix}}$ oder ${\begin{bmatrix}0&1\\0&0\end{bmatrix}}$, respectively, in the tensor product construction.)

Now consider, for instance, the products

$\omega =v_{1}v_{2}\dots v_{k}$

${\bar {\omega }}=w_{1}w_{2}\dots w_{k}$ (Complex conjugate if V is real Euclidean space)

Then the left-ideal Cl(V) ω is a spinor representation. Moreover, the idempotent ${\bar {\omega }}\omega$ gives the projection onto this representation.

This more-or-less gives an explicit connection between the isotropic spaces and the orthogonal idempotents approach to arriving at the spin reps.

Sorry if this looks like a mess, I'll try to give you a cleaner presentation later. Silly rabbit 17:29, 6 May 2007 (UTC)

I'm now replying in part to your recent reply on my talk. The two approaches (idempotents versus isotropic spaces) are indeed related by an $\omega {\bar {\omega }}$-type construction (as indicated in my confusing meanderings above). Here ω is a generator of the upper-most wedge product of an isotropic space W (actually W′ in the Explicit construction notation) with itself. The annihilator of this generator consists of products of the complement of the isotropic space. A few things remain to be done, however,

1. Somehow give a "physical" or geometrical interpretation of the various operators involved (as you have done in the case of the Lorentzian projections).
2. Find an easy way to show that $\omega {\bar {\omega }}$ is idempotent (up to an overall constant, at least).

Anyway, I'm glad you brought this up since the two ways are certainly related, and it's worth exploring the precise relationship. Silly rabbit 13:51, 7 May 2007 (UTC)

Mathematical Physics

Hey Jheald, I noticed that you commented on the Mathematical Physicsarticle, albeit over a year ago. As such I thought I would let you know that this article is nominated for the Math Collaboration of the week (I nominated it). Even if this article does not make the cut, it needs serious work and I am not qualified to do it as of yet. If you get the time please take a look at it; if not, I understand, and thanks for your time--Cronholm144 01:09, 10 May 2007 (UTC)

Mandelstamm

Hello, this is a message from an automated bot. A tag has been placed on Mandelstamm, by Shoeofdeath, another Wikipedia user, requesting that it be speedily deleted from Wikipedia. The tag claims that it should be speedily deleted because Mandelstamm fits the criteria for speedy deletion for the following reason:

Housekeeping - cleanup per WP:SU

To contest the tagging and request that administrators wait before possibly deleting Mandelstamm, please affix the template {{hangon}} to the page, and put a note on its talk page. This bot is only informing you of the nomination for speedy deletion, it did not nominate Mandelstamm itself. Feel free to leave a message on the bot operator's talk page if you have any questions about this or any problems with this bot. Thanks. --Android Mouse Bot 2 00:13, 25 May 2007 (UTC)

First of all, calm down. I am sorry for removing the warning, I have done this before and people have thanked me for it. Second, it is clear that you are unaware of the extent of the WP:SU project. Hundreds of redirects are being deleted daily (most created by SU), and sometimes ones that are not exactly bad such as Mandelstamm are deleted. If you would like to re-create that as a redirect, feel free, it would not be deleted again.

Surname pages do not generally include all spellings of a name. Also, such pages are meant to direct other people to articles on Wikipedia, not give extra information. The amount of redlinks to include has been discussed already, and generally they are deleted if they do not have extensive "what links here" connections.

Note that I did not nominate Mane-Katz for deletion, which I could have after you removed the prod. It is my personal opinion that such stubs detract from the quality of Wikipedia. Am I not allowed to have such an opinion?

Sweeping PRODs of articles despite potential, and/or content on other wikis, and/or source text from reliable sources (eg Jewish Encyclopaedia).

Sweeping prods? I have prodded about 10 articles, and you are in no position to tell me what has potential. That is my opinion. If you disagree, remove the prods. Again, calm down. shoeofdeath 17:15, 25 May 2007 (UTC)

Regarding edits to Vector (spatial)

Thank you for contributing to Wikipedia, Jheald! However, your edit here was reverted by an automated bot that attempts to remove spam from Wikipedia. If you were trying to insert a good link, please accept my creator's apologies, but note that the link you added, matching rule \bmembers\.aol\.com\/.+, is on my list of links to remove and probably shouldn't be included in Wikipedia. Please read Wikipedia's external links guidelines for more information, and consult my list of frequently-reverted sites. For more information about me, see my FAQ page. Thanks! Shadowbot 21:19, 25 May 2007 (UTC)

Vector: Agree

I agree with your assessment of my recent edit. But the article needs some structural work, and we need an organized overview of things, I think. It would be nice to make it more elementary. Silly rabbit 12:30, 26 May 2007 (UTC)

Moreover, as far as I could tell, the old "Definitions" section didn't say anything consistent. I didn't think it was pitched at an elementary level, since you basically already needed to know about vectors (and bases!) to understand it properly. I'm going to try to do away with the section entirely, but try to reorganize the article around these fundamental ideas: geometry (Euclidean space), algebra (Cartesian coordinates), affine properties (addition/scalar multiplication), metric properties (norm, dot product, {cross product in 3D}), and physics interpretations. The material is there, but it needs some top-level restructuring. Silly rabbit 12:50, 26 May 2007 (UTC)

Reply: It's completely standard to do vector addition and scalar multiplication before introducing the dot product and length. See Strang "Introduction to Linear Algebra", Apostol "Calculus". Furthermore, I'm sure we both agree that this is the proper way to do things from a mathematical point of view, since length is an extra structure imposed on the vectors. Also, if you want to talk about the dot product, then you more or less have to have the an idea of vector addition and scalar multiplication in place already: The dot product is bilinear. For length, you have the triangle inequality. The compromise I am aiming for is to make this article suitable for linking from other more sophisticated articles (many of which may not assume a metric), but to preserve the elementary treatment. Some sectioning for easier navigation doesn't hurt either.

Also, I don't entirely agree with your view

But against that, consider that we're introducing vectors in simplest terms as objects with a magnitude and a direction.

That's fine for an intuitive interpretation of vectors, but it's not entirely accurate. Even in physics, incompatible units may not allow for a definition of magnitude. I think the subtleties of working this into the text, as other authors have tried to do (incorrectly, at that!) will make it far less readable. Treating vectors as directed line segments is just as intuitive, and if the reader wants to imagine length before it is formally defined, then I'm sure they're going to do that anyway. Silly rabbit 15:31, 26 May 2007 (UTC)

canonical ensemble

The point of notionally coupling a large number of copies together is to get an easy model of a heat bath and a straightforward transition from the stats for a microcanonical ensemble. It may be 'grossly wrong' but it's the way (IIRC, and I did check last time I had to justify it) I was taught it at Part 2! Bob aka Linuxlad 12:38, 26 May 2007 (UTC)

Cube Microplex pagemove

Hi there; what convention are you following in moving Cube Microplex to Cube Microplex, Bristol? So far as I know, wikipedia policy is to only have extra ", placename" for districts of cities or states, and otherwise we use "pagename (disambiguation type)" for disambiguating article titles. Is there some policy I don't know about with respect to this? Your move doesn't appear to be the only one for bristol-related articles so I'd like to track down who else is doing this. Kellen^T 10:33, 2 June 2007 (UTC)

Re: Beatles discography

Not rely, maybe a case could be made for using the cover of one or two of the most noteworthy albums mentioned in the "Historical background" section along with the text there, but most of it is still just a list with names, track listing, release dates, chart possissions and such. There is no actual commentary on individual albums (aside from the "Historical background" section), and that's as it should be. Detailed commentary belong in the articles about the individual albums (where using the cover art is fine as far as I'm concerned), not in the discography list. --Sherool (talk) 16:57, 5 June 2007 (UTC)

Re: CSD I6

Evidently, from your comment in talk CSD, you don't agree with suspending I6.

But the locus for this discussion has been WT:FAIR#Way forward, and there does seem to be consensus that this suspension is the appropriate thing to do, while attempts are made to clean up the tag mountain in ways that will minimise collateral damage, and bruising inflicted on ordinary Wikipedians.

If you don't agree, please enter into the discussion at WT:FAIR#Way forward.

In the meantime, it would be appropriate to suspend I6, pending this discussion.

Will you back out your revert, and leave I6 suspended, at least for the time being? Jheald 11:17, 9 June 2007 (UTC)

If you want to alter the criteria for speedy deletion, you ought to propose any change at Wikipedia talk:Criteria for speedy deletion; many editors who are concerned with the business of deletion will have that page on their watchlists and expect to see proposals suggested there. If you really want to propose a change, I suggest you do one that is confined in operation to the images that BetacommandBot has been tagging. --bainer (talk) 11:23, 9 June 2007 (UTC)

I have to be away from the net for the rest of the weekend. I simply cannot be online any longer. Please, can you draft something that you think is appropriate? There are 30,000 images BCbot has tagged, most of which can be legitimised - given the time to do it. Starting now deleting them all blindly cannot be the way to go. See also the depth of controversy and discussion at WP:AN/FURG. This is not (yet) the time for starting a mass deletion. Jheald 11:52, 9 June 2007 (UTC)

I won't be drafting anything because I think I6 is working fine. These images have had plenty of time already to be "legitimised"; the requirement for rationales has been present since the first processes to deal with non-free media were developed, and I6 was introduced more than a year ago. It's not the end of the world if images are deleted before someone gets to preparing a rationale, since image undeletion has been available for a year now. --bainer (talk) 12:02, 9 June 2007 (UTC)

Just some time to avoid the pain and aggravation this is going to cause. For the Project's sake as a whole. Is that so much to ask? Jheald 12:04, 9 June 2007 (UTC)

Convincing me won't be any use; if you want the policy changed you need to build a consensus at Wikipedia talk:Criteria for speedy deletion. I'll carry on carrying it out until it changes, and if it does, I'll carry out what it says then. --bainer (talk) 12:14, 9 June 2007 (UTC)

Hamiltonian mechanics

Hi, I did a merge of Hamiltonian mechanics and Hamilton's equations, please let me know what you think, is it what you had in mind? Regards sbandrews (t) 11:03, 10 June 2007 (UTC)

Thanks

Hello Jheald. I just wanted to leave a note saying thanks for fixing the Mark Antony link on the I, Claudius page. I am usually pretty thorough about making sure that my link doesn't cause a redirect and when I saw your correction I realized that all of the other names were in the cast list, which is where I was linking them from, but because MA was already dead at the time the story begins he wasn't in that list I had forgotten to double check his link. So thanks again and happy editing. MarnetteD | Talk 13:46, 27 June 2007 (UTC)

User of Image:Jasmine Guy Album.jpg and the fair use rationale you gave

Jheald, we do not permit the use of fair use album covers in discography lists such as that which was found at this version of Jasmine Guy. Thus, the rationale in this case is invalid. I've removed the image from the discography and tagged the image as an orphaned fair use. Thanks, --Durin 14:21, 13 July 2007 (UTC)