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Article milestones Date Process Result July 23, 2006 Good article nominee Not listed October 25, 2007 Good article nominee Not listed November 10, 2007 Good article nominee Listed November 30, 2007 Peer review Reviewed Current status: Good article

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Archives

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web site reliable source?

There is a web site "About Pi. Ask Dr. Math FAQ" - it is used as a ref four times. It does not strike me as a reliable source. My intention, when I see refs like this, is to replace them with reliable secondary sources listed in the new References section. I don't see any material yet that should be outright deleted, but the sourcing is relying too much on primary sources. So, I don't foresee too many changes: just replacing a few cites; consolidating some material; improving the prose a little bit. --Noleander (talk) 20:04, 17 March 2012 (UTC)

This is not a reliable source. I say kill it. Also, it is attached to the word "Euclidean" in the lead. In my opinion, this word should be eliminated entirely. Links to Euclidean geometry should be worked in less artificially elsewhere in the lead. (But IMO the lead will need to be rewritten completely after the rest of the article is updated, so this is not an urgent matter.) Sławomir Biały (talk) 00:45, 27 March 2012 (UTC)

See also section & Indiana pi bill

The FA criteria suggest that an ideal article should not have a "see also" section, on the theory that a truly comprehensive article's body would mention (& have a link to) any related article. This article has about 5 articles in the See also section, including the Indiana pi bill (and it is also mentioned in the Approximations of π subarticle). I suggest adding a very brief mention of that article somewhere in the article .. perhaps in some "crackpot" paragraph about continued attempts to square the circle after 1882. Personally, I have no objection to See Also sections in FA articles, but moving such articles into the body is a desirable goal. --Noleander (talk) 20:35, 17 March 2012 (UTC)

I don't thinks that's the case. Lot's of featured articles have See also sections. In the case of this article, it's clear that a see also section is needed to accommodate certain topics that would not meet the requirements of WP:WEIGHT if they were included in the main text. Examples are the Indiana Pi Bill, and Tau (2π). In my opinion, such topics should not be discussed in the main article, as they are totally peripheral to the subject. They can, however, be farmed out to sub-articles if there is scope for expansion in that direction (e.g., Pi in politics or some such.) Sławomir Biały (talk) 00:50, 27 March 2012 (UTC)

Sounds good. I have no objections to See Also sections. --Noleander (talk) 01:29, 27 March 2012 (UTC)

Another web site source

I just stumbled on this citation: which is used three times in the article. I propose to replace it with a more reliable source. --Noleander (talk) 16:31, 20 March 2012 (UTC)

I thought MacTutor History was okay? Dmcq (talk) 18:46, 20 March 2012 (UTC)

The web site is http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Pi_through_the_ages.html. It does not appear to be reliable. I'm not familiar with what web sites the Math project has adopted as acceptable, but in my opinion, anything other than http://mathworld.wolfram.com/ is not satisfactory. --Noleander (talk) 19:31, 20 March 2012 (UTC)

Well we have a small article about it MacTutor History of Mathematics archive and there are links to reviews. I'd have thought it would be okay as it is written by recognized authorities. If you can find better sources though no problem about replacing. Dmcq (talk) 19:26, 20 March 2012 (UTC)

Yes, there are many reliable sources (books published by university presses, etc) so there is really no need to be using web sites at all. --Noleander (talk) 19:30, 20 March 2012 (UTC)

Consensus in the past has been that MacTutor is an acceptable reference, but where possible it should be supplemented with a better source. I should add that Wolfram's MathWorld is not particularly reliable either. It's not peer reviewed, and is largely the work of a single non-mathematician. What few topics in my specialty areas MathWorld has articles on, they are often full of errors, invented notations, and other inconsistencies with the published literature. MacTutor has a much better reputation for historical accuracy than Wolfram (this is based on reviews of both), and MacTutor is something of a de facto standard for history of mathematics in the same way as MathWorld is for certain other topics. Sławomir Biały (talk) 13:55, 25 March 2012 (UTC)

Charters of sections need to be clarified

The article has a few sections whose charters are a bit fuzzy:

1. Pi#Irrationality and transcendence - Does not include a discussion of normal or random
2. Pi#Decimal representation - Includes the "39 digits are sufficient" issue; & irrationality & randomness
3. Pi#Estimating the value - Includes some history & formulae
4. Pi#History - history & formulae

I think the material is good, but the sections could be cleaner if they were reorganized as follows:

1. Properties - (irrationality, transcendental, etc)
2. Randomness - (incl why interesting to mathematicians; Is it normal? statistical tests of randomness, Feynman point, etc)
3. Approximations - (include decimal/hex representations; and some well known coincidental equations)
4. History (leave as-is)
5. Motivation for high accuracy - ("39 digits is sufficient"; bragging rights; exercise supercomputers; test high-precision arithmetic algorithms, provide data for analyzing randomness of digits, etc)

I'm not proposing to remove any material, simply to clarify the charters of the sections and move things around a bit to better track the secondary sources. Thoughts? --Noleander (talk) 10:33, 22 March 2012 (UTC)

I think normality (I think the word randomness should be avoided) can just be included as part of the discussion on properties. That fact that it's an open question is cool. Also, the note about π's irrationality measure can be included here. I prefer Estimating the value or Estimations over Approximations, but that is just a personal preference. The rest looks good. Cheers, Ben (talk) 22:55, 22 March 2012 (UTC)

It might also be worth renaming the Geometric definition section to Definition so we can include a more proper discussion of how we can define π. Cheers, Ben (talk) 23:01, 22 March 2012 (UTC)

The above proposal has been implemented, including Ben's suggestions. --Noleander (talk) 20:36, 30 March 2012 (UTC)

Buffon's needle in Probability section?

The Pi#Probability and statistics section contains a couple of paragraphs on pi and Buffon's needle. The context of that section is showing how pi appears (usually unexpectedly) in various scientific disciplines .... the example (in that section) of pi in gauss normal distribution is a great example. But Buffon's needle problem is circular/trigonometric in nature, and pi is expected there. So, I think Buffon's needle is better treated (in this article) as a monte carlo approach to estimating pi. So perhaps the Buffon's needle material should be split out into a new section "Monte Carlo estimations". That new section could also include the dart board approach to calculating pi (which is described in Approximations_of_π#Summing_a_circle.27s_area, but is not yet in the pi article). Thoughts? --Noleander (talk) 11:40, 22 March 2012 (UTC)

This has been done: A new section on Monte Carlo methods was created, and the Buffon needle material was moved into it. --Noleander (talk) 20:37, 30 March 2012 (UTC)

Contradiction on most accurate calculation before computers.

Under Estimating the value it says (under the greyed "image" to the right) "A calculation of π accurate to 1120 decimal digits was obtained using a gear-driven calculator in 1948, by John Wrench and Levi Smith. This was the most accurate calculation of π before electronic computers came into use." while under Infinite series it says (last paragraph) "Infinite series based on the arctan function generally converge much faster than other infinite series, and were used to set records for the next 300 years, culminating in a 620 digit approximation in 1946 by Daniel Ferguson – the best approximation calculated without the aid of an electronic computer."
At least one of those two statements must be false - or?
Also Chronology of computation of π says that in 1949 D. F. Ferguson and John Wrench (not John Wrench and Levi Smith in 1948) calculated π with 1120 decimals and the page on John Wrench says that he and Levi Smith used a desk calculator to calculate π with 1160 decimals during 1945 to 1956. I.e. yet some more contradictions...
--Episcophagus (talk) 17:33, 26 March 2012 (UTC)

Thanks for pointing out that error. According to Arndt, p 205, the records were:

620 digits in 1946 by Ferguson - manual (no calculator)

808 digits in 1948 by Ferguson & Wrench - used a desk calculator

1,120 digits in 1949 by Smith & Wrench - used a desk calculator

2,037 digits in 1949 by Reitwiesner - on ENIAC electr computer

I'll straighten the article out to be correct. --Noleander (talk) 18:10, 26 March 2012 (UTC)

John Wrench himself writes (in this link, page 322):

"With the collaboration of Levi B. Smith (...) the writer computed π to 818 places by February, using a desk calculator. The result was published to 808 places in April 1947 (...) Collation of this 808-place approximation with results obrtained by Ferguson later that year revealed several erroneous figures behind the 723rd place (...) Correction of these errors and extensions of Ferguson's results appeared in a joint paper by Ferguson and the writer in January 1948, which concluded with an 808-place approximation to π of guaranteed accruacy. Subsequently, Smith and the writer resumed their calculations and by June 1949 had obtained an approximation to about 1120 places. (...) In November 1954, Smith and the writer extended their calculation to 1150 places, and in 1956 reverted to this work once more to attain their final result, which was terminated at 1160 places, of which the first 1157 agree with those obtained on the ENIAC."

--Episcophagus (talk) 18:15, 26 March 2012 (UTC)

Thanks for that info. I think it is consistent with material from the Arndt secondary source. I find it interesting that they continued working until 1956 to get up to 1,160 digits, when ENIAC had already gotten up to 2,000 digits in 1949. I've updated the article to be accurate now, speak up if you see any other errors. --Noleander (talk) 18:27, 26 March 2012 (UTC)

In the same book as I linked to above (on page 280) the 1950 article by Reitwiesner is also (in part) published. There π is given by 2035 places, not 2037.

--Episcophagus (talk) 18:52, 26 March 2012 (UTC)

"Geomorphology and chaos theory" section

The section titled "Geomorphology and chaos theory" seems a bit fishy to me. First, it says " Albert Einstein was the first to suggest that rivers have a tendency towards an ever more loopy path because the slightest curve will lead to faster currents on the outer side ..." which I find hard to believe. Second, the word "chaos" does not appear in the text of the section, so why is it in the title? I'll do some research and make sure the material reflects the sources, but if anyone has some thoughts, please speak up. --Noleander (talk) 03:25, 4 April 2012 (UTC)

Done: i removed Einstein and "chaos", and re-worded to simply reflect what the source says. --Noleander (talk) 15:22, 10 April 2012 (UTC)

Illustration vs. NavBox at top of article?

The picture of a rolling wheel at the top of the article is really, really good. Probably worth more than a thousand words. But, there is also the convention that sidebar navboxes, if present in an article, are placed in the upper right corner of the article. So, we should have a discussion about whether the rolling wheel should be above or below the sidebar navbox. When this article achieved GA status in 2007, the rolling wheel was at the top, but that was before the sidebar navbox was introduced in May 2010. There is an archived Talk page discussion on which should be on top, from May 2011, but it was inconclusive. Personally, either way seems okay; I can see arguments both ways. But I am planning on nominating this for FA status soon, so we should probably have the discussion and get consensus one way or another. --Noleander (talk) 14:55, 4 April 2012 (UTC)

Or merge them. Easier to show this than describe it so I've gone ahead and done it, but only on this page using a parser function in Template:Pi box. Seems to work and have not broken anything. It could instead be changed to always use that image or even use it based on a parameter in the infobox (that might be a more standard way to do it).--JohnBlackburne_deeds 15:07, 4 April 2012 (UTC)

Great solution! --Noleander (talk) 15:14, 4 April 2012 (UTC)

Remove conjecture?

The "Properties" section contains the following sentence:

"Bailey and Crandall showed in 2000 that the existence of the Bailey–Borwein–Plouffe formula and similar formulas imply that the normality of π in base 2 can be reduced to a plausible conjecture of chaos theory."

I read the source, but it doesn't seem to warrant inclusion in this article. The way I read it is the authors have some ideas, but they have not proven anything yet. There must be hundreds of "plausible conjectures" about pi, but we cannot include them all in this article. Unless some strong secondary sources mention this conjecture, I suggest removing it. Thoughts? --Noleander (talk) 17:54, 4 April 2012 (UTC)

It is quite an old ref so, unless anyone can show signs of progress in this theory or continued interest in it in a good source, I would say delete. If someone can give a half-decent reason to keep I would not argue. Martin Hogbin (talk) 20:09, 4 April 2012 (UTC)

Done: I removed it. --Noleander (talk) 15:23, 10 April 2012 (UTC)

Bulleted lists in the "In mathematics and science" section?

The subsections of "In mathematics and science" use a variety of approaches to text formatting: the Number Theory, Geometry and trigonometry, and River sections use a simple prose paragraph. The Physics and Probability sections use a bulleted technique. The Complex numbers and calculus sections are non-bulleted, but list-like. I think the big question is: Should the sections use bullets? or avoid bullets? The MOS says "Do not use lists if a passage is read easily as plain paragraphs." I believe that the Featured Article reviewers, in general, view bullets unfavorably. Looking at the text in question, I see no harm in removing the bullets. One upside is that it will induce editors to add textual background & explanation of the formulae, and thus make it more informative to lay readers. Thoughts? --Noleander (talk) 14:12, 5 April 2012 (UTC)

I removed the bullets, and converted to plain text. --Noleander (talk) 15:21, 10 April 2012 (UTC)

Examples of trig definitions

The Definitions section currently has 5 sample definitions based on trig:

• π is the smallest positive x for which sine(x) equals zero
• π is the smallest positive x for which cosine(x) equals –1 (π = arccos(–1))
• π is twice the smallest positive x for which sine(x) equals 1 (π = 2 arcsin(1))
• π is twice the smallest positive x for which cosine(x) equals zero (π = 2 arccos(0))
• π is four times the smallest positive x for which tangent(x) equals 1 (π = 4 arctan(1))

Most sources that mention this kind of definition only cite 1, 2 or 3 examples. I'm wondering if having 5 would give readers the wrong impression that these are critical, and all five are significant somehow? Maybe trim down to 2 or 3? --Noleander (talk) 03:38, 7 April 2012 (UTC)

I just trimmed it down to three - one for each trig function. — Glenn L (talk) 01:20, 9 April 2012 (UTC)

Pronunciation in Greek

The following sentence in the Name section either says the same thing twice (that in English, we pronounce π as "pie") or erroneously says that Greeks also pronounce it this way: In English, π is pronounced as "pie" (/ˈpaɪ/), which is the same pronunciation used for the Greek letter. Joseph Lindenberg (talk) 21:31, 9 April 2012 (UTC)

Thanks for pointing that out ... I'll fix it. --Noleander (talk) 21:38, 9 April 2012 (UTC)

Use of pi before William Jones

What I had read was that William Oughtred used ⁠π/δ⁠ to represent ⁠perimeter/diameter⁠ since π and δ are the Greek equivalents of p and d. I read this in the last paragraph of this article. He cites page 292 of Pi: A Source Book as his source. I also see it mentioned in the book The Joy of Pi. See the 5th page here. Joseph Lindenberg (talk) 22:29, 9 April 2012 (UTC)

Yes, I have (for another 2 days :-) Pi: A Source Book ... and indeed that fact does appear. It appears that π was used by Oughtred not in the modern sense (a ratio = circum/diam) but rather simply to mean circumference (or periphery). So, that fact does not directly bear on the number π, although it does provide some historical background. Maybe I'll put it in a footnote for now ... putting it in the prose may cause more confusion than enlightenment. --Noleander (talk) 23:51, 9 April 2012 (UTC)

Okay, I put that in as footnote #6: " See Schepler, p 220: William Oughtred used the letter π circa 1630 to represent the periphery (i.e. circumference) of a circle." --Noleander (talk) 23:55, 9 April 2012 (UTC)

Magnetic permeability not a good example

I'd like to hear other people's opinions on this, but I don't think magnetic permeability ${\displaystyle \mu _{0}=4\pi \cdot 10^{-7}\,\mathrm {N/A^{2}} \,}$ is a good example to use. The presence of π in it is entirely man-made and arbitrary. Scientists set the size of SI units to produce that result. (It was done so that the 4π would cancel out the 4π in formulas like the Biot-Savart Law.) They could just as easily have set the size of their units to make ${\displaystyle \mu _{0}}$ equal their favorite lottery number. You'll notice that none of the other physics formulas listed have units attached. Using the Biot-Savart Law instead would just seem more intellectually honest. (Ultimately though, the 4π in it and in Coulomb's law come from the 4π in the surface area of a sphere.) Joseph Lindenberg (talk) 02:09, 10 April 2012 (UTC)

Tend to agree. --Trovatore (talk) 02:16, 10 April 2012 (UTC)

I replaced the magnetic permeability formula with the Biot-Savart Law. If another formula would be superior, speak up. --Noleander (talk) 04:16, 10 April 2012 (UTC)

As Joseph Lindenberg says, many laws of physics that contain pi essentially just reflect the formula for the surface area of a sphere and the system of units used. This does not necessarily mean that we should not mention them here but I would suggest that we have at most just one such formula, as an example of pi being used in physics. Martin Hogbin (talk) 08:28, 10 April 2012 (UTC)

I see no problem with removing 1 or 2 of the physics formulae, if they are not adding anything to the article. That section does begin with the disclaimer: "Although not a physical constant, π appears routinely in equations describing fundamental principles of the Universe, often because of π's relationship to the circle and to spherical coordinate systems." Two that are a bit duplicative are Einsteins field equation & the cosmological constant immediately following it. --Noleander (talk) 13:37, 10 April 2012 (UTC)

Peer review soon

I'm still planning on nominating the article for FA status. There are a few tasks remaining, such as ensuring that all citations are uniformly formatted; validating all citations to make sure they support the material in the article; and reviewing the lead to make sure it is a good summary of the entire article. After that, I'll open up a peer review request and then, if the PR outcome is good, nominate for FA. If any editor has suggestions or ideas for improvement, please speak up! --Noleander (talk) 16:59, 10 April 2012 (UTC)

Firstly, well done so far. Just a few thoughts:

Is the lead a good summary of the article as a whole?

Why now "piems", in quotes, rather than pilish which has its own article.? Martin Hogbin (talk) 17:14, 10 April 2012 (UTC)

I have not looked at the lead yet: I figure it is better to wait for the body of the article to settle down, and only then do the lead. At first glance, the lead looks okay, but it doesn't seem to mirror the body very closely (not that it has to slavishly follow the body). As for piem vs. pilish: Yes, it looks like that could be clarified & improved. There seem to be several overlapping concepts: Piphilology (any mnemonic technique to memorize pi's digits); pilish (any story/poem with word-lengths that represent pi's digits); and piems (rhyming pilish). I'll see if I can improve the article to clarify all that. --Noleander (talk) 17:25, 10 April 2012 (UTC)

I agree with you about the lead; it is not at all bad and it is best to wait until the body is complete but I guess we are nearly there now. Martin Hogbin (talk) 17:44, 10 April 2012 (UTC)

I improved the section on memorizing digits. I looked in the secondary sources, and none of the three terms (piphilology, piem, or pilish) appear much ... the authors just speak of "memorizing" or "mnemonics". I removed "pilish" from this article, because the sources just dont use it. I left in piphilology and piem, but even those I'm not sure about. A good case could be made for renaming the article piphilology to Memorizing pi, but I won't go down that path. If anyone think the Memorizing section could be improved in any way, please speak up. --Noleander (talk) 20:15, 10 April 2012 (UTC)

Rivers & pyramids

An editor removed material on pyramids & the meandering river. I restored the pyramid material, because it is discussed in many reliable secondary sources on pi. Perhaps that text could be improved to make it clearer that most modern scientists/egyptologists don't think that pi was involved in the pyramid shapes, but total removal is a bit much. The meandering river material is not as widely discussed by 2ndary sources, although it is in the Posamentier source. So that is less clear case for inclusion ... although it is a great example of unusual places in the sciences where pi pops up, which is the point of that section. Thoughts? --Noleander (talk) 19:52, 10 April 2012 (UTC)

Unless someone objects, I propose to restore the "meandering river" example to the article because it serves to illustrate the ubiquitous nature of π. --Noleander (talk) 03:18, 11 April 2012 (UTC)

Include rope around equator?

There is a rather famous paradox involving pi: if a rope is wrapped tightly around the equator; then lengthened by 10 meters; then made into a perfect circular shape and lifted above the earth's surface (but still centered on the earth's center): How high is the rope above the earth's surface. Most people expect a small value, like a few millimeters, but the answer is nearly 2 meters. I realize this is rather trivial puzzle, and the article should not be a collection of brain teasers, but I've seen this particular paradox in many, many sources, and it seems like something that would be informative to a lay reader. Thoughts? --Noleander (talk) 16:37, 11 April 2012 (UTC)

I've not heard this particular brain teaser before. If you find it commonly used in discussions of pi, then it might be appropriate to include just for that reason. But what it describes would also be true if the Earth were a giant cube. The rope would rise 10/8 of a meter. So this is not really a pi-related phenomenon. Joseph Lindenberg (talk) 00:25, 12 April 2012 (UTC)

Yeah, I guess you're right. I'll leave it out. I wonder if there is a WP article that holds brain teasers? --Noleander (talk) 00:47, 12 April 2012 (UTC)

String_girdling_Earth Joseph Lindenberg (talk) 01:05, 12 April 2012 (UTC)

Wow, a whole article on it! Thanks for pointing that out. --Noleander (talk) 01:25, 12 April 2012 (UTC)

Glad I could help. Joseph Lindenberg (talk) 01:34, 12 April 2012 (UTC)

Featured article update

A peer review was done by user User:RJH at Misplaced Pages:Peer review/Pi/archive2. User User:Jakob.scholbach has volunteered to do an additional review, which is great. After that second review is done, the article should be ready to go to FAC. Thanks to all editors that have helped by making improvement to the article, often correcting my infelicitous wording. --Noleander (talk) 14:20, 15 April 2012 (UTC)

I am in the process of doing a quick review, correcting minor wording issues in the process. Feel free to revert any changes if you disagree. Nageh (talk) 14:26, 15 April 2012 (UTC)

I didn't think I should start a new section below this one, so I'm posting this here. Also, sorry for bringing this up a bit late in the process.—After someone reads in the Name section that a capital pi means something different mathematically (a product), they might be confused to see what look like capital pi's in a few places on the page. (Contents list, circle squaring drawing, first line of History section, first line of Usage section) It might help if the Name section also explained that in some fonts, a lower-case pi isn't curvy and thus looks like an upper-case pi. I suspect a lot of less-technical readers aren't aware of that whole issue and wouldn't immediately figure it out. --Joseph Lindenberg (talk) 08:20, 17 April 2012 (UTC)

I took a stab at writing it in. Feel free to revert or modify. --Joseph Lindenberg (talk) 10:43, 17 April 2012 (UTC)

We've had two great editors provide input at the peer review so far. A third editor, User:Jakob.scholbach, has said they will provide more input some time this week. My plan is to resolve the issues raised by the 3rd reviewer; then make one final pass thru the article for prose quality; then take it to FAC; probably in May. --Noleander (talk) 13:15, 18 April 2012 (UTC)

I closed the PR on this article, because I'm starting a new PR on another, unrelated article (an editor can have only one open PR at a time). If anyone wants to submit more comments or reviews, please do so here on the Talk page, or start a new PR. I've notified User:Jakob.scholbach, and I hope they can find some time for a review. --Noleander (talk) 22:57, 20 April 2012 (UTC)

In regards to my comment on the Approximations section in the PR, maybe it would help to rename it to Other approximations or Other approximation methods. That could make it more clear why some of the approximation methods are actually being discussed in the History section. Nageh (talk) 15:18, 21 April 2012 (UTC)

Done: renamed to Other approximations. --Noleander (talk) 18:33, 21 April 2012 (UTC)

Images of mathematicians

The article feels overcrowded with images, especially images of mathematicians. I think that ultimately the images should be thinned, starting with those of mathematicians. The images of mathematicians really don't provide any additional detail that is useful in understanding the article. Although sometimes such images can provide visual cues for some readers, they are probably counterproductive in an article already rich with (mathematical) imagery. Sławomir Biały (talk) 12:15, 18 April 2012 (UTC)

Well, for one I think the huge pi symbol should go again. It has no additional value at that place, IMO. Nageh (talk) 12:21, 18 April 2012 (UTC)

It seems a little more relevant that an image of Euler, but that's just my humble opinion. Also, the mosaic image seems particularly out of place in the continued fraction section (and it might interfere with the display of the equations in that section on some browsers). Sławomir Biały (talk) 12:30, 18 April 2012 (UTC)

Indeed, while the mosaic images is a nice one it just doesn't fit there. But maybe we should first think about how to organize the History and the Approximations sections before we think about images. Nageh (talk) 12:57, 18 April 2012 (UTC)

Regarding the photo of a mosiac of pi: I have no objection to removing that one. It is a nice image, and could probably go in the Popular culture section, but that section already has an image. --Noleander (talk) 13:05, 18 April 2012 (UTC)

Sorry, I just removed an image, without realizing that a discussion was on-going about the images. Regarding the pics of mathematicians: I think they are great. They are colorful, and make the article more inviting to lay readers. This is not just any math article: it is of great popular interest, and has a lot of history intertwined. This article is #433 in WP visitation rank. The German article on pi reached featured art status, and has lots of excellent portraits of persons involved with pi. The FA criteria explicitly asks for illustrations. What I'd recommend is: if the images within a particular section are too numerous (larger than the section text) then the image of a person should be removed in favor non-person image. --Noleander (talk) 12:59, 18 April 2012 (UTC)

That would remove quite a lot of images. Indeed, (colorful) images of important figures can make an article more inviting to the layman, and that is certainly important. Nageh (talk) 13:02, 18 April 2012 (UTC)

Maybe I was not clear: I was not proposing to remove any images, or any images of persons. I was just saying that if there were a small section that could hold only 1 picture, and there was a really informative diagram, and a portrait of a mathematician, then the diagram would probably be better, if we had to pick 1 of the 2. But, now, in the article, I don't see a need to make such a choice. --Noleander (talk) 13:05, 18 April 2012 (UTC)

pi font: curve vs straight

An editor recently added the sentence " In some fonts though, a lower-case π lacks curves and looks very similar to a capital Template:PI. " in to the name section. I'm not sure if it belongs there: it seems rather obscure ... I've removed it temporarily, so we can discuss here and figure out the best way to proceed. I think the editor was motivated (as indicated in edit history comment) by the fact that some of the diagrams in the article use a font for pi that looks straight-line-ish, almost like a capital PI. The editor, correctly, was concerned that readers may get confused by seeing the curvy pi in the text; yet the straight-line pi in some diagrams. One solution would be to fix the diagrams to use a curvier pi font. Another would be to insert a sentence like " In some fonts though, a lower-case π lacks curves and looks very similar to a capital Template:PI. " Another would be to do nothing. Thoughts? --Noleander (talk) 13:12, 18 April 2012 (UTC)

I did realize that we could just fix the 5 places in the article with uncurvy π's and search thoroughly for any others. But it seemed like useful information to provide the reader. They'll encounter this issue in other places even if we do successfully eliminate all instances of it from this one page on this one site on the internet. On the other hand, the only reason it seemed truly necessary to mention it was that the article said capital pi was never used to represent 3.14 and meant something different mathematically. If you remove that and just don't say anything about capital pi, at least the potential for confusion would be eliminated. --Joseph Lindenberg (talk) 02:01, 19 April 2012 (UTC)

I don't think there's much potential for confusion. In most fonts, lower case 'v' looks very similar to capital 'V', but people cope, because it's generally the case that capital and lower case letters are different sizes. Also, the meaning is usually clear enough from the context; I don't think people could interpret π in the diagrams for this article as a product. Jowa fan (talk) 03:27, 19 April 2012 (UTC)

The squaring-the-circle picture is the worst occurence, because there's no surrounding text to compare the height of the π to. I'm really not saying that people will think the π is meant to signify a product there. I'm saying they'll be confused (and therefore unimpressed) that the article seems to not even follow its own statement that you should never use capital Template:PI to represent 3.14. Regarding your example of the letter v, the difference here is that everyone is used to seeing a lower-case v with straight lines. But (at least outside the country of Greece) most non-technical people aren't used to seeing a lower-case π with straight lines. So they're more likely to interpret what they see there as being an upper-case Template:PI. --Joseph Lindenberg (talk) 05:23, 19 April 2012 (UTC)

I gave it a try. Have a look, feel free to revert if you disagree. Nageh (talk) 10:59, 19 April 2012 (UTC)

Looks good to me. --Joseph Lindenberg (talk) 21:09, 19 April 2012 (UTC)

This does seem to be a problem that keeps coming up with people saying that the Greek letter shouldn't have an italic form for instance. In Template:LaTeX \pi is counted as a maths symbol, not a Greek letter. In Unicode they have the same encoding but that doesn't make them the same thing. If somebody has a good reference about this it might be worth putting in to point to when people say we should have the straight leg form because that's what the Greeks used. Dmcq (talk) 11:26, 19 April 2012 (UTC)

tau material?

I just reverted an edit that added a paragraph about tau. I don't have a big objection to some very minor mention of tau in the article, but there should be a discussion about the material first here on the Talk page (because it is relatively controversial and has been discussed before on the Talk page). I suggest that editors that want to add material supply a proposal here, including sources which focus on pi. --Noleander (talk) 03:23, 22 April 2012 (UTC)

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