Talk:Phi

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.

More about Phi

In the book, The Da Vinci Code, 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 (UTC)

Somewhat true, mostly exaggerated. See Golden ratio. —Tamfang 18:35, 28 May 2006 (UTC)

The empty set symbol

The letters Φ (obtained by typing &Phi;), φ (&phi;) or ${}{}\phi$ (<math>\phi<<\math>) 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;) 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 $\emptyset$ (<math>\emptyset</math>) looks funny and seems to dance above the baseline.

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

—Herbee

Similarly, there's a Unicode diameter symbol, ⌀ (&#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)

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 φι, 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.

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 [1], 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, Θ, Φ and Ψ 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 Φ 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 Φ and TH instead of Θ.

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. —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 → pf → f. (I am not a linguist but I play one on television.) You think that's curious, look up Grimm's Law. —Tamfang 05:47, 22 March 2006 (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'. —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. —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." [2]

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#Rendering_math, 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#Forced_PNG_rendering

—DIV (128.250.204.118 07:50, 14 April 2007 (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))

Orphan question

i Have a question what are the unusual relationships to moderm times?