Talk:Phi/Archive 1

More about Phi
In the book, The Hobbit, it talks about all this crazy stuff regarding Phi, and how it's a building block for life or something. Like if you measure your height from the tip of your head to the ground, and your waist to the ground, the ratio is equall to Phi. And the same goes for your fingers, arms, and alot of stuff in nature. Is this true? —Preceding unsigned comment added by 24.109.177.107 (talk • contribs) 21:15, 27 May 2006


 * Somewhat true, mostly exaggerated. See Golden ratio.  &mdash;Tamfang 18:35, 28 May 2006 (UTC)

The empty set symbol
The letters &Phi; (obtained by typing &amp;Phi;), &phi; (&amp;phi;) or $${}{}\phi$$ (&lt;math&gt;\phi<&lt;\math&gt;) are not the symbol for the empty set in mathematics, and should not be used as such in Wikipedia.

In Unicode, the empty set symbol &#8709; (&amp;#8709;) occupies code point U+2205. But many fonts in use today don't include this character and render it as a small rectangle.

The TeX symbol $$\emptyset$$ (&lt;math&gt;\emptyset&lt;/math&gt;) looks funny and seems to dance above the baseline.

Therefore, I recommend using either &Oslash; (&amp;Oslash;) or {} ({}) to indicate the empty set.

&mdash;Herbee


 * Similarly, there's a Unicode diameter symbol, &#x2300; (&amp;#x2300;) which should probably be used instead of or in addition to the image being used on the page; I don’t know how widely-supported the symbol is. -Ahruman 07:36, 18 October 2006 (UTC)

History???
Where did Φ originate from (symbolically)? Tdinatale (talk) 17:04, 10 August 2009 (UTC)

Transliteration
Does anyone have any idea why it's transliterated into the modern Latin alphabet as "ph"? It's always seemed odd to me, even more odd than other two-letter combinations that make separate sounds, like "sh" and "th" -- in those cases, the mouth/lips/tongue are at least in a similar position to the normal pronunciation of the letters preceding the "h". And especially because we have a letter for this. It's called F. Is there any particular reason why these words/roots are not spelled like "filosofy" and "fobia", or was it just a fluke of language development that became tradition?
 * Don't know, but if it's a comfort to you, english and french are about the only two languages that do it. There was a lot of treating labiodentals as labials, see Tengwar.

Lee S. Svoboda 22:31, 1 Apr 2005 (UTC)

I don't really KNOW, but the following, cut-and-pasted from H2G2, seems relevant:


 * The Early Roman Alphabet


 * The Latins adopted writing from both the Etruscans and the Western Greeks in about the 5th Century. They had no use for the Z, &#920;, &#934; and &#936; characters of the Western Greek alphabet, so they dropped them from their alphabet.


 * The Romans needed a letter to represent the f sound in their language. The Etruscan language didn't have an f sound, and neither did Western Greek. (The Greek &#934; was at that time pronounced ph, that is, a p with an h sound after it). They adapted the Etruscan letter F which was pronounced 'w' and gave it the sound 'f'.


 * They adopted an Etruscan three-lined zig-zag S and then curved it to make the modern curvy S. They used the Gamma < to represent both the Etruscan K sound and the Greek G sound. The early Roman alphabet looked like this:


 * A B C D E F H I K L M N O P Q R S T V X


 * There are a few differences from the modern alphabet:


 * C represented both the hard 'k' sound in 'cat' and the 'g' sound in 'garden'.
 * I represented both the vowel we call 'i' and the 'y' sound that we get at the start of the word 'yellow'.
 * V represented both the U sound of 'put' and a consonantal sound which was somewhere between our 'v' and 'w'.


 * [...]


 * The Eastern Greek Influence


 * In the 3rd Century BC, the Greeks led by Alexander the Great conquered all of the Eastern Mediterranean and east as far as India. Over the next few centuries, knowledge also spread out from Greece in all directions and the Romans absorbed a lot of ideas from Greek culture. Greek words started to be used in Latin. There was a need to be able to write down these words. The Romans transliterated most of the letters, making do with such combinations as PH instead of &#934; and TH instead of &#920;.


 * But they had no way of writing two particular Greek sounds, so in about 100 AD, the Romans borrowed two letters from the Eastern Greek alphabet. One was Y, which was very much the same as the V they had already got from Western Greek. In Eastern Greek it had retained a long stem while in Western Greek it had lost it. The Eastern Greek pronunciation was by now slightly different as well. It is the slender U sound we get in the German word 'fünf' or the French 'tu'. The other letter the Romans borrowed was the Zeta Z for the z sound. Both the Y and the Z were only used for writing Greek words so the letters were placed at the end of the alphabet, although Z had centuries before been positioned after F.


 * So by the time the Roman Empire reached its peak, the alphabet looked like this:


 * A B C D E F G H I K L M N O P Q R S T V X Y Z


 * Due to the Roman dominance of Europe, the Roman alphabet became the standard alphabet throughout Western Europe, and eventually was spread throughout the Western World.

--Niels Ø 09:57, Apr 2, 2005 (UTC)

The Greek phonemes ph, th, kh were originally aspirated stops (as in Hindi) not fricatives. It may well be that they had not yet become fricatives when Latin started borrowing words from Greek. &mdash;Tamfang 23:20, 25 February 2006 (UTC)
 * But how did the sounds change to fricatives?? Georgia guy 00:11, 15 March 2006 (UTC)


 * Perhaps there was an intermediate affricate stage, i.e. the aspiration became a homorganic fricative and then the stop dropped: ph &rarr; pf &rarr; f. (I am not a linguist but I play one on television.)  You think that's curious, look up Grimm's Law. &mdash;Tamfang 05:47, 22 March 2006 (UTC)

I know this is late and many people may not like this answer at all but here is what really happened (and it isn't so exciting really).

The Egyptians had the glyphs (picture writting) that poor people turned into just symbols representing sounds. Of the original glyphs there were about 6000. 200 of those became the letters used by the common people. Then the Hebrew people had contact with Egypt and adopted 22 of those letters to write their language. The shape of the letters got gradually simpler with each new group that adopted it. Each letter in fact stood for several different sounds and spelling was far from standardized. Also, the letters only stood for consonant sounds, with the unseen vowel sounds just being supplied by the reader. This is in part what allows semitic pepoles today to have the exact same writting system, same cosonants in a word but pronounce it differently from area to area.

The magic moment that separates the Consonant only kind of writting from the Alphabetic writting with shown vowel sounds happened in Greece.

Now I know some people are going to disagree with what I am about to write but all the evidence I have seen in ancient text informs me of the truth of it.

When the Greeks borrowed the Hebrew (phonoecian) alphabet they took six of the letters and made them into vowel sounds. Two of these letters represented sounds that just did not exist in Greek at all. The others were only seldomly used.

Now I won't get into what each letter became so I will focus on Φ.

The letter that Phei was created from was a semitic letter that looked like a staff with an almost closed circle at the top. This letter in the Semetic languages represented W, Wh, V, Vr, F, Fr, OO (u), and the U sound in the word UP. How it was pronounced depended on who was saying it and which semetic language they spoke. It was also written slightly differently from tribe to tribe. The Greeks took the letter and Adapted it. They broke it into three letters. The first was of course Upsilon, with is a stick with a rounded top but the two sides were widened into a bowl. The second was Phei, which originally looked like a stick with the circle on the top, but as writters used the letter they began to write the circle part first instead of second and this had the effect of increasing the size of the circle and the stick became a line that went through the center (similar to qoppa). As Qoppa had follen out of use rather fast, this produced no problem. The third letter was Digamma, which just put the opening to the side instead of the top and squared it off. Upsilon was the V sound, Phei was the F sound and Digamma was the W sound. Upsilon also did duty as the OO sound. It later changed to a Yoo sound and then finally it was completely ionified and now sounds like EE.

The reason Phei gets transliterated into Latin as PH is due to the fact that the Latin F was harder than the Greek PH. In Latin the F sound is made by touching the lower lip to the top teeth. In Greek this sound was made by lightly separating the lips and making a HOO sound. Also, in ancient times, Latins and Greeks actually thought they used the same alphabet and were happy to transliterate words and sounds but since the shape of the letters they used for this sound differed, they wanted to use something else so that they would know from which Greek letter it came from so that if need be, they could transliterate it back into Greek.

The Romans were exposed to the writting of the world from several sources, the punics, Etruscans and the Greeks. It isn't like they sent a manned expidition to Greece to learn writting. These letters were out there in the market place and the Romans just picked them up. They borrowed Y and turned the shape of it into V and it stood for the V sound (a voiced F sound produced by touching the bottom lip to the top teeth). It also stood for the OO sound. If they Romans encountered people who had the W sound they used the OO sound to aproximate it but the Romans themselves did not have this sound in their native language. So a person named Walter would have a Roman trying to say his name and hearing OO-al-ta-r. The claudian digamma was breifly used for the W sound in Latin but since it was only needed for foriegn words it was never fully adopted to write native words in Latin.

So there you have it. Phei equals F and both dirive from the same source letter in Semitic but for historical and cultural reason are maintained as seperate letters. —Preceding unsigned comment added by 219.127.251.137 (talk) 05:34, 1 October 2008 (UTC)

Variants
Why are there two versions of the lowercase phi? --Abdull 13:26, 15 June 2006 (UTC)


 * For much the same reason as two versions of lowercase 'a'. &mdash;Tamfang 03:07, 16 June 2006 (UTC)


 * Interestingly, the different versions of phi have their own code points in character sets such as Unicode while there exists only one code point for the lowercase 'a', despite different versions. So there aren't moments when it is more appropiate to use one version of the lowercase phi instead of the other? --Abdull 16:57, 19 June 2006 (UTC)


 * From the way they're written, it looks like the swirly one is more for handwriting and the other one is for printing. Just a guess. Also, I think there is a code point for the a that looks like o|, buried deep in Unicode. 218.102.71.167 12:57, 20 June 2006 (UTC)


 * Yes, the two forms of 'a' are distinguished in the International Phonetic Alphabet, the simpler form being more "back" than the other. &mdash;Tamfang 02:17, 21 June 2006 (UTC)


 * The lede here tries to display the letter phi in four different ways; unfortunately, all of them display on my browser (Firefox on Ubuntu Edgy, using Bitstream Vera Serif) as the cursive variant. Part of this is due to this bug in MediaWiki's handling of maths markup. I've corrected one use of the unicode character which assumes the straight glyph where we can't guarantee that, but unfortunately this bug means it still looks the same. Hairy Dude 02:37, 16 December 2006 (UTC)
 * Update: Setting "Always render PNG" in your maths preferences makes it look right. Hairy Dude 20:20, 20 December 2006 (UTC)


 * The use of so-called variants confuses me too. As noted by Hairy Dude above, rendering in readers' browsers may not be what the article contributors expect.  For example, the sentence "The lower-case letter φ (or often its variant, \varphi)" renders basically the same glyph twice with my settings — once as a Unicode character, and once as an image (not shown here).  In both cases the glyph appears as an incomplete circle with downstroke.  The problem is that U+03C6 renders in this way in some fonts (e.g. Times New Roman, Arial), but as a complete circle with slash in other fonts (e.g. Palatino Linotype).  Just to confuse things still further, at the article's mention of U+03D5 (sometimes) the character is rendered as what I can best describe as rho (ρ) mirrored on its downstroke.  ("Sometimes", because as I flip between tabs and adjust the font size in my browser, the glyph keeps on changeing between this and the incomplete circle with downstroke!  Perhaps a realisation of the bug referred to above??)
 * Beyond this, the Unicode Code Chart shows U+03C6 as incomplete circle with downstroke, and U+03D5 as complete circle with slash. ...although this should be read with the disclaimer "[...] the charts do not specify the exact shape; they only provide a representative shape for identification."
 * By the way, Hairy Dude, I'm also using Firefox (v1.5.0.10), and can't figure out where the "Always render PNG" setting is that you mentioned.
 * — DIV (128.250.204.118 07:13, 5 March 2007 (UTC))


 * *Answering own question*
 * I've now found the "Always render PNG" option at Help:Preferences, but it only works for people who log in ...to view the page! (At least, as far as I can see.)  So fairly useless, I would have thought, for the majority of article readers.
 * — DIV (128.250.204.118 05:49, 18 March 2007 (UTC))
 * *Answering own question* (again)
 * Refer to WP:FORMULA
 * —DIV (128.250.204.118 07:50, 14 April 2007 (UTC))

Reversed
As noted above Palatino Linotype reverses the glyphs for phi and phi symbol. That is, the 'letter' U+03C6 renders as $$\phi\,\!$$, while the 'symbol' U+03D5 renders as $$\varphi\,\!$$. Here is another example, DatapageMath4 from Mathtype. —DIV (128.250.80.15 (talk) 07:48, 4 February 2009 (UTC))

Lucida Sans Unicode also more-or-less reverses the glyphs. The 'letter' U+03C6 renders as $$\phi\,\!$$, whereas the 'symbol' U+03D5 renders as the 'mirrored-rho' described above, which looks something like $$\mathrm{\varphi}\,\!$$, but with the left-hand curve joined to the top of the stem. Cyrillic 'ф' is rendered in a similar fashion, except that for U+03D5 the stem has no ascender, and the curve from left to right is smooth at the bottom. [ ф in turn appears like a mirrored version of thorn, þ. ] (Evidently the reason the mirrored-rho variant glyph sometimes appeared on my system was that my default font in some applciations is Verdana, which doesn't support the character U+03D5.) —DIV (128.250.247.158 (talk) 07:19, 2 March 2009 (UTC))

Nullity
http://www.bbc.co.uk/berkshire/content/articles/2006/12/06/divide_zero_feature.shtml Ben 20:38, 7 December 2006 (UTC)

Ph and f
Why does this article neglect that ph and f aren't the same letter? (in latin and greek at least ph is softer) 82.18.172.41 12:24, 15 December 2006 (UTC)

Co-ordinates
A third spherical co-ordinate system convention is to measure positive φ up from the x-y plane to the z-axis. (Third in the sense of besides the two currently listed, not in the sense of third-best!) Don't know what fancy name to call this, but it could/should be added to the article to avoid bias. — DIV (128.250.204.118 07:23, 5 March 2007 (UTC))

"Variant" glyph?
The sentence,

"The lower-case letter $$\varphi \,$$ (or often its variant, $$\phi \,$$) is often used..."

seems to imply that "varphi" refers to the standard glyph, while phi refers to the variant form!

This seems wrong, though I assume it was intentional. Why is it like this? —Preceding unsigned comment added by Dratman (talk • contribs) 13:47, 13 November 2009 (UTC)


 * Just a suspicion which I doubt I'll be able to confirm, but it's likely that varphi is the actual Greek letter, while phi is a bastardization of ease. --Izno (talk) 14:53, 13 November 2009 (UTC)

It's not. $$\phi \,$$ is the correct form. I'm pretty sure that $$\varphi \,$$ is ypsilon. But I know $$\phi \,$$ is right. --N3g4t1v3z3r0 (talk) 23:37, 14 December 2009 (UTC)
 * Um, no. Greek ypsilon is υ ($$\upsilon\,$$) in lowercase, Υ ($$\Upsilon\,$$) in uppercase. Both the $$\varphi\,$$ and $$\phi\,$$ glyphs are variants of lowercase phi.—Emil J. 16:45, 2 April 2010 (UTC)

Usage
Is not the uppercase Phi a symbol for physics wheres Psi is the symbol for philosophy? Greetings, PassPort --87.144.71.113 (talk) 14:52, 22 January 2011 (UTC)

Phi in First-order Logic
This Wikipedia entry http://en.wikipedia.org/wiki/Predicate_calculus shows Phi being used to represent a sentance. I was just reading about it, so someone more knowledgable should fix the entry. — Preceding unsigned comment added by 69.180.204.245 (talk) 17:25, 29 July 2011 (UTC)

Pronunciation
The article says it's pronouced fee, but every lecturer and school teacher I've ever had (in Physics, Maths and Computer Science) has pronounced it fie. Does anyone know why this is? Is it an English vs. Greek vs. American difference in pronunciation? -- Karl Naylor 14:35, 23 May 2004 (UTC)

I have researched this pronunciation over the last several weeks pretty extensively (because somehow I have an itch that just must be scratched). The references I have found are distributed fairly evenly across three groups: 'fee', 'fie', and 'both'. Generally, those references that claim authority in a scientific or mathematical context generally claim 'fee'. Those references that are authoritative in Greek language studies claim either 'fie' or 'both'. In my college experience (math, physics, computer science), most instructors or professors used 'fee'. However, and curiously, many times the same instructors would pronounce the names of certain Greek association houses as 'fie', as in Phi Beta Kappa. Personally, I prefer 'fie' although in any case, I think the article should mention both pronunciations as being acceptable, depending upon context. -- Jim Richins, 29 June 2004

Everyone I know says fee, except my older brother who says fie, but hes a loser, so dont mind him. Fie as in pi & chi &c., but fee to be cool and know what you're talking about. daesotho 20:25, 15 Sep 2004 (UTC)

"Fee" is the actual Greek pronunciation (written &phi;&iota;, I believe). I've heard it pronounced both ways, but probably more commonly as "fee" in an academic setting. For what it's worth, the American Heritage Dictionary gives both pronunciations. Merriam-Webster gives only "fye". Personally, I say "fee", but to each one's own. Caesura 02:42, 19 Mar 2005 (UTC)


 * "Fie" is more common in .uk/.au/.nz English (in particular in mathematics, engineering and science done there). Don't remember what they say in .ca.  Actually going by national stereotypes, koowoos would pronounce it "Foo" and Canadians "Feh?", but that's another story.  Andrew Kepert 05:53, 21 Mar 2005 (UTC)


 * Anyone who doesn't know where 'fie' comes from should read about the Great Vowel Shift. ፈቃደ (ውይይት) 17:04, 14 March 2006 (UTC)

Maybe the source of confusion is that a word spelled "fie" or "fye" or "f'eye" (or whatever else) could be pronounced in a number of ways. Using IPA might clear things up a bit.

This dispute can be settled by noting the visual similarity between phi and theta; as the former resembles the latter turned sideways, it's known to some students as "gangsta theta". —Preceding unsigned comment added by 74.95.38.204 (talk) 03:52, 16 November 2009 (UTC)


 * I generally associate the "fie" people with mathematics and comp. sci., while "fee" with classicists. As a person who did a significant amount of stradling between those two worlds, I actually pronounce them differently depending on whether I am reciting the alphabet (fee), or reading about the golden ratio (fie). I also pronounce ξ, ψ, χ and π as "ksee", "psee", "khee" and "pee". VIWS talk 03:39, 28 July 2011 (UTC)

Orphan question
i Have a question what are the unusual relationships to moderm times? — Preceding unsigned comment added by Kimon (talk • contribs) 17:26, 29 July 2011 (UTC)

phi in parallel computing
In parallel computing, phi is sometimes used to represent the fraction of time a computer program runs in parallel. — Preceding unsigned comment added by 81.33.111.249 (talk) 19:43, 18 March 2012 (UTC)

Edit request on 3 April 2012
The article states that phi is used to denote electric potential. Electric potential is measured in Volts and is denoted by a V. "Φ" is used to measure electric flux, not electric potential. Electric flux is the result of the change in an electric field through a given area. Specifically, Electric flux is equal to the integral of the Electric field with respect to differential units of area. In other words: Φ=∫E·dA. This is general knowledge within the field of Physics, and is even found on the Wikipedia page on electric flux. Please change "electric potential" to "electric flux." Thank you.

199.8.13.16 (talk) 20:08, 3 April 2012 (UTC)
 * Sure. --Izno (talk) 20:28, 3 April 2012 (UTC)

Phi is used for flux, but it is also commonly used to represent potential. — Preceding unsigned comment added by 139.80.236.34 (talk) 06:08, 8 August 2012 (UTC)

Source Request
Since when does phi represent 500 in the Greek numeric system? I was given to understand that Greek numerals were on base 24, with phi representing 22/24 just as 8 represents 8/10 in our base 10 system. Regrettably, I don't have a good source and so am wondering if there can be consensus that either a source should be provided for the "500" statement or we can remove it. Thoughts? 131.252.4.4 (talk) 18:53, 25 May 2012 (UTC)


 * You are misinformed, Greek numerals operate on a base 10 system. There are 24 letters in the Greek alphabet, but they have never used a base-24 counting system.  Wikipedia has a good and accurate article on Greek numerals if you'd like to learn more. --145.226.30.45 (talk) 10:30, 26 November 2012 (UTC)

Semi-protected?
This article was semi-protected in 2010 for "ongoing high risk of vandalism". Nothing was added to the talk page by the person in charge of semi-protecting the article, and no actions of vandalism can [ttbomk] be found in the article history. I would like to revoke the protection of this article. Rgiusti (talk) 11:45, 29 January 2013 (UTC)
 * There are several cases of vandalism on this page. For example,, , and .--94knux (talk) 23:42, 11 February 2013 (UTC)

LaTeX representation
The article states, that the TeX representation of whereas Help:Displaying a formula - Wikipedia, the free encyclopedia, Hilfe:TeX – Wikipedia, LaTeX-Kompendium: Sonderzeichen – Wikibooks, Sammlung freier Lehr-, Sach- und Fachbücher, states it should be the other way round Doing some research refering to LaTex-editors and generators I've found many systems, that use this literals differently. Is this not well defined? Voeren (talk) 08:37, 13 February 2013 (UTC)
 * φ is \phi
 * ϕ is \varphi
 * φ is \varphi
 * ϕ is \phi
 * In TeX, \phi is the stroked form of the character, and \varphi the loop form. In contrast, as you could read in this article if someone didn’t rather unhelpfully delete the explanation a month ago (the original version: ), there is variation among fonts as to which form the Unicode characters φ and ϕ have. Thus, claiming any 1–1 correspondence between the Unicode characters and TeX symbols is simply wrong, nevertheless the intention (not always followed) of the Unicode standard is that ϕ (U+03D5 GREEK PHI SYMBOL) should always have the stroke form, and as such corresponds to \phi, contrary to what our article states. Whether φ corresponds to \phi or \varphi is font-dependent.—Emil J. 13:17, 13 February 2013 (UTC)
 * I have restored the original information, and reformatted the rest without so much redundant detail.—Emil J. 14:01, 13 February 2013 (UTC)
 * Thank you EmilJ, that made it a lot more understandable. But shouldn't we make it even clearer by stating that the current Unicode chart clearly defines the loopy form on 03C6? Maybe in the column "Correct appearance"
 * {| class="wikitable"

! Character !! Name !! Correct appearance !! Your browser !! Usage
 * U+03C6 || GREEK SMALL LETTER PHI || style="text-align: center;" | (  prior to Unicode 3.0 ) || style="font-size: larger; text-align: center;" | &#x03C6; || used in Greek texts
 * U+03D5 || GREEK PHI SYMBOL || style="text-align: center;" | ( prior to Unicode 3.0 ) || style="font-size: larger; text-align: center;" | &#x03D5; || used in mathematical and technical contexts
 * } Voeren (talk) 13:32, 18 February 2013 (UTC)
 * U+03D5 || GREEK PHI SYMBOL || style="text-align: center;" | ( prior to Unicode 3.0 ) || style="font-size: larger; text-align: center;" | &#x03D5; || used in mathematical and technical contexts
 * } Voeren (talk) 13:32, 18 February 2013 (UTC)


 * No, it does not, that’s the point. Both forms are fine for 03C6, in accordance with Greek typography. The sample glyphs in the Unicode tables are not a normative part of the standard.—Emil J. 14:06, 18 February 2013 (UTC)
 * Ok, now I see this as well. But so I have another proposal to communicate this fact clearer, integrating a quote from the referenced unicode document. I've directly changed it in the document Voeren (talk) 16:10, 18 February 2013 (UTC)

Phi
Okay, how far should this go out: 1.6180339887 4989484820 4586834365 6381177203 0917980576 2862135448 6227052604 6281890244 9707207204 1893911374 8475408807 5386891752 1266338622 2353693179 3180060766 7263544333 8908659593 9582905638 3226613199 2829026788 0675208766 8925017116 9620703222 1043216269 5486262963 1361443814 9758701220 3408058879 5445474924 6185695364 8644492410 4432077134 4947049565 8467885098 7433944221 2544877066 4780915884 6074998871 2400765217 0575179788 3416625624 9407589069 7040002812 1042762177 1117778053 1531714101 1704666599 1466979873 1761356006 7087480710 1317952368 9427521948 4353056783 0022878569 9782977834 7845878228 9110976250 0302696156 1700250464 3382437764 8610283831 2683303724 2926752631 1653392473 1671112115 8818638513 3162038400 5222165791 2866752946 5490681131 7159934323 5973494985 0904094762 1322298101 7261070596 1164562990 9816290555 2085247903 5240602017 2799747175 3427775927 7862561943 2082750513 1218156285 5122248093 9471234145 1702237358 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5915944111 7250923132 7977113803


 * Is there no other place on the Web for this list of digits? A few of them are given in Golden ratio, but none are relevant to the present article about a letter. —Tamfang (talk) 06:54, 15 July 2014 (UTC)

Pronunciation
Fixed and sourced from OED. The Ancient Greek pronunciation could use a better source, though: I just used the automated formatting they have over at Wiktionary. — Llywelyn II   04:16, 6 October 2014 (UTC)

The empty set?

 * Perhaps Jakesyl would like to remind us how a long list of digits is more appropriate to the talk page than the following question, which the digits replaced. —Tamfang (talk) 06:52, 15 July 2014 (UTC)

No mention of phi as the empty set? Barry.carter (talk) 23:07, 11 August 2013 (UTC)
 * Isn't there something in the article about other symbols that resemble phi? —Tamfang (talk) 09:30, 12 July 2014 (UTC)
 * Well, good this is here. Otherwise, I wouldn't believe that people could confuse those symbols... — Llywelyn II   04:16, 6 October 2014 (UTC)
 * http://en.wikipedia.org/wiki/Empty_set#Notation — Preceding unsigned comment added by 81.82.234.87 (talk) 14:59, 10 November 2014 (UTC)

Semi-protected edit request on 8 October 2016
To add to existing list ending with line: "In lexical-functional grammar, the function that maps elements from the c-structure to the f-structure."

The symbol for Relative Humidity

92.251.24.209 (talk) 12:03, 8 October 2016 (UTC)


 * Looks like the entry is there. — Andy W. ( talk ) 00:22, 13 October 2016 (UTC)

Meaning in AI?
In artificial intelligence, a lowercase phi symbol has a standard meaning that escapes me at the moment. Perhaps if someone knows what I'm talking about, it could be added to this page? --5.198.44.45 (talk) 10:58, 15 May 2018 (UTC)

Pronunciation
The article claims: The modern Greek pronunciation of the letter is sometimes encountered in English (as ) when the letter is being used in [the mathematical/scientific] sense. There is no source for this claim (unless it's the book, which I can't verify). It seems more likely to me that the editor who wrote this heard scientists / mathematicians whose first language is not English simply using their native pronunciations while speaking English. Hairy Dude (talk) 12:55, 28 February 2019 (UTC)

I have personally heard native English speakers pronounce it that way, both scientists and classicists. — Preceding unsigned comment added by 68.172.33.135 (talk) 15:29, 9 March 2019 (UTC)

Semi-protected edit request on 27 February 2019
Upper Case Phi is also used in electrical power engineering a short hand for phase (as in Single Phase = 1Φ, Three Phase = 3Φ, Six Phase = 6Φ) 203.26.73.3 (talk) 05:08, 27 February 2019 (UTC)
 * Already in the article - "The number of phases in a power system in electrical engineering, for example 1Φ for single phase, 3Φ for three phase." &#8209;&#8209; El Hef  ( Meep? ) 15:42, 27 February 2019 (UTC)
 * This is not at all true. Φ is reserved in electrical engineering for magnetic flux. 1Φ is one webber of flux although Wb is more commonly used as an SI unit to avoid confusion with Ø. I can find no documentation in IEEE, NSPE, NCEES that uses Φ for phase. It would be incredibly confusing to use the same symbol. Electrical Engineering uses the symbol Ø. "My high side calculations found 3Φ on AΦ, 2Φ on BΦ, and 3Φ on CΦ in the 3Φ transformer." It should say "My high side caculations found 3Φ on AØ, 2Φ on BØ, and 3Φ on CØ in the 3Ø transformer." That is a lot less confusing because the same symbol doesn't mean two different things in the same sentence.


 * In mathematics phase can be denoted by Φ,θ,or Ø. Because Φ is flux and θ is phase angle, Ø is used to denote phase. This is the same reason math uses i for imaginary numbers and electrical engineers use j. i is current in electrical engineering. Yet when you type in 'symbol for electrical phase' this page pops up first. This incorrect and uncited claim needs to be fixed ASAP. 74.124.124.66 (talk) 19:57, 20 May 2020 (UTC)

Additional Example for the Use of Phi as a Symbol
Phi is the symbol for the world of Phyrexia in the story of the card game Magic: The Gathering.

Edit: here's an article from wizards of the coast (the company who owns magic: the gathering) about the symbol: https://magic.wizards.com/en/articles/archive/phyrexian-symbol-again-2011-05-18 Dodo Axolotl (talk) 16:26, 28 May 2022 (UTC)
 * Red information icon with gradient background.svg Not done: please provide reliable sources that support the change you want to be made. Secondary sources are needed to show that this is noteworthy. ScottishFinnishRadish (talk) 16:39, 28 May 2022 (UTC)
 * Hoping that counts as a reliable source! Dodo Axolotl (talk) 12:04, 2 June 2022 (UTC)

Semi-protected edit request on 8 June 2022
CHANGE "In probability theory, ϕ(x) = (2π)−1⁄2e−x2/2 is the probability density function of the standard normal distribution." to "In probability theory, ϕ(x) = (2π)−1⁄2e−x2/2 is the cumulative distribution function of the standard normal distribution." 138.51.72.65 (talk) 23:15, 8 June 2022 (UTC)
 * Red information icon with gradient background.svg Not done: please provide reliable sources that support the change you want to be made. ScottishFinnishRadish (talk) 23:22, 8 June 2022 (UTC)

Semi-protected edit request on 10 January 2023
CHANGE "In philosophy, φ is often used as shorthand for a generic act. (Also in uppercase.)" to "In philosophy, φ (or Φ) is often used as shorthand for a generic act."

Applimu (talk) 23:27, 10 January 2023 (UTC)
 * Red information icon with gradient background.svg Not done: The section is specifically split up into two sections: lowercase and uppercase, so I believe the note is sufficient, especially as it is listed in both sections. ~ <b style="color: #00733f">Eejit43</b> ( talk ) 14:55, 17 January 2023 (UTC)