Editing Phi (section)

== Unicode ==
In [[Unicode]], there are multiple forms of the phi letter:
{| class="wikitable"
! Character !! Name !! Correct appearance !! Your browser !! [[LaTeX]] !! Usage
|-
| <code>{{U+|03A6}}</code> || {{nowrap|GREEK CAPITAL LETTER PHI}} || style="text-align: center;" | <math>\Phi\,\!</math> || style="font-size: larger; text-align: center;" | Φ || <math>\Phi</math> || Used in Greek texts
|-
| <code>U+03C6</code>|| GREEK SMALL LETTER PHI || style="text-align: center;" | {{nowrap|{{GrGl|phi Didot}} or {{GrGl|phi Porson}}}} || style="font-size: larger; text-align: center;" | φ || {{nowrap|<math>\varphi</math> or <math>\phi</math>}} || Used in Greek texts
|-
| <code>U+03D5</code>|| GREEK PHI SYMBOL || style="text-align: center;" | ϕ || style="font-size: larger; text-align: center;" | ϕ (''ϕ'') || <math>\phi</math> || Intended for use in modern (monotonic) Greek texts. Used italicized in mathematical and technical contexts when the "straight-line" variant glyph is preferred.<ref name="unicode-math">{{cite book | url = http://unicode.org/reports/tr25/#_Toc231 | title = UTR #25: Unicode support for mathematics | chapter = Representative Glyphs for Greek Phi | format = [[PDF]]}}</ref>
|-
| <code>U+0278</code>|| LATIN SMALL LETTER PHI || style="text-align: center;" | [[File:Xsampa-pslash.png|15px]] || style="font-size: larger; text-align: center;" | ɸ || <math></math> || Used in [[International Phonetic Alphabet|IPA]] to denote a [[voiceless bilabial fricative]]
|}

In ordinary Greek text, the character U+03C6 φ is used exclusively, though this character has considerable glyphic variation, sometimes represented with a glyph more like the representative glyph shown for U+03C6 (φ, the "loopy" or "open" form), and less often with a glyph more like the representative glyph shown for U+03D5 (ϕ, the "stroked" or "closed" form).

Because Unicode represents a character in an abstract way, the choice between glyphs is purely a matter of font design. While some Greek typefaces, most notably those in the [[Porson (typeface)|Porson]] family (used widely in editions of classical Greek texts), have a "stroked" glyph in this position ({{GrGl|phi Porson}}), most other typefaces have "loopy" glyphs. This also applies to the "Didot" (or "''apla''") typefaces employed in most Greek book printing ({{GrGl|phi Didot}}), as well as the "Neohellenic" typeface often used for ancient texts ({{GrGl|phi Neohellenic}}).

It is necessary to have the stroked glyph available for some mathematical uses, and U+03D5 GREEK PHI SYMBOL is designed for this function. Prior to Unicode version 3.0 (1998), the glyph assignments in the Unicode code charts were the reverse, and thus older fonts may still show a loopy form <math>\varphi</math> at U+03D5.<ref name="unicode-math"/>

For use as a phonetic symbol in [[International Phonetic Alphabet|IPA]], Unicode has a separate code point U+0278, LATIN SMALL LETTER PHI, because only the stroked glyph is considered correct in this use. It typically appears in a form adapted to a Latin typographic environment, with a more upright shape than normal Greek letters and with [[serif]]s at the top and bottom.

In [[LaTeX]], the math symbols are <code>\Phi</code> (<math>\Phi\,\!</math>), <code>\phi</code> (<math>\phi\,\!</math>), and <code>\varphi</code> (<math>\varphi\,\!</math>).

The Unicode standard includes the following variants of phi and phi-like characters:

* {{unichar|0278|html=}}
* {{unichar|03A6|html=}}
* {{unichar|03C6|html=}}
* {{unichar|03D5|html=}}
* {{unichar|1D60|html=}}
* {{unichar|1D69|html=}}
* {{unichar|1DB2|html=}}
* {{unichar|2C77|html=}}
* {{unichar|2CAA|html=}}
* {{unichar|2CAB|html=}}
* {{unichar|1D6BD|html=}}
* {{unichar|1D6D7|html=}}
* {{unichar|1D6DF|html=}}
* {{unichar|1D6F7|html=}}
* {{unichar|1D711|html=}}
* {{unichar|1D719|html=}}
* {{unichar|1D731|html=}}
* {{unichar|1D74B|html=}}
* {{unichar|1D753|html=}}
* {{unichar|1D76B|html=}}
* {{unichar|1D785|html=}}
* {{unichar|1D78D|html=}}
* {{unichar|1D7A5|html=}}
* {{unichar|1D7BF|html=}}
* {{unichar|1D7C7|html=}}