3

Is there a way to apply iota subscripts to arbitrary alphabets in math mode ?

An example is ῳ.

  • As in ᾳ ? Not really, not out of the box, what purpose do you have in mind? I mean, I'm sure you could make it happen but why? – Au101 Mar 14 '17 at 3:01
  • Yes, I have some purposes and just curious to see if the iota subscripts can be applied in math mode. – Johannes Mar 14 '17 at 3:03
  • What's an iota subscript? @Au101 ? – cfr Mar 14 '17 at 3:10
  • 2
    @cfr The iota is the greek letter ι, it's the Greek i. In Ancient Greek (not sure about Modern) it can form a sort of compound with the letters α η and ω where a small version is placed underneath: ᾳ ῃ ῳ. This is known as the iota subscript. These are read as diphthongs with the first vowel long: en.wikipedia.org/wiki/Iota_subscript – Au101 Mar 14 '17 at 3:14
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    ῳ is equivalent to ωι, which can be considered as an abbreviation for the latter form. The ι sound was originally pronounced but was lost later so the form ῳ was introduced to capture the original etymology perhaps. (see en.wikipedia.org/wiki/Iota_subscript for details) – Johannes Mar 14 '17 at 3:29
5

You can basically use anything as a centered subscript:

\documentclass{article}
\usepackage[LGR,T1]{fontenc}
\usepackage{amsmath}

\newcommand{\adscriptiota}{{%
  \usefont{LGR}{cmr}{m}{n}\symbol{"7C}%
}}

\DeclareRobustCommand{\ai}[1]{{\mathpalette\doai{#1}}}
\newcommand{\doai}[2]{%
  \oalign{%
    $#1#2$\cr
    \hidewidth$#1\text{\adscriptiota}$\hidewidth\cr
  }%
}

\begin{document}

$\ai{\alpha}\ai{b}\ai{\gamma}$

\end{document}

enter image description here

If you want special positioning under particular letters, you have to do it by hand. The case of letters with descenders is tough, as exemplified by \gamma.

  • Thanks a lot! Is the syntax \usefont{LGR}{cmr}{m}{n}\symbol{"7C} determine the form of the iota subscript here ? – Johannes Mar 14 '17 at 7:59
  • @Johannes Yes, you can use other font families instead of cmr, provided they have support for LGR. – egreg Mar 14 '17 at 8:03
  • Sorry, I was not sure about the mechanism of displaying a image here. I was wondering it might be better to not use the letter b here but a more challenging one such as g here to show the position of iota subscripts. – Johannes Mar 14 '17 at 10:11
  • @Johannes I'll do it. – egreg Mar 14 '17 at 10:16

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