Greek directly in math mode XeLaTeX instead of PdfLatex

Question

This piece of code

\documentclass{article}  
\usepackage{alphabeta} 
\usepackage{amsmath}
\begin{document}
$α+β+γ=\alpha+\beta+\gamma$
\end{document}

works perfectly in MiKTeX-TeXworks provided that I use the option pdfLatex.

However greek letters are ignored by when I use the XeLaTeX option.

I want to use XeLaTeX and yet be able to write greek letters directly in math mode.

Is this possible?

If yes how should I modify the above piece of code?

Please extend your example to a full document (there is no documentclass) — daleif, Jul 28 '22 at 12:42
use unicode-math not alphabeta and you will be able to use all Unicode math characters — David Carlisle, Jul 28 '22 at 14:19
Somewhat special case of Entering Unicode characters in LaTeX - TeX - LaTeX Stack Exchange, for cross-linking purposes. — user202729, Jul 29 '22 at 05:18

score 7 · Accepted Answer · answered Jul 28 '22 at 14:23

7

You can use unicode-math with xelatex and lualatex, it includes amsmath

\documentclass{article}
\usepackage{unicode-math}
\begin{document}
$α+β+γ=\alpha+\beta+\gamma$
\end{document}

answered Jul 28 '22 at 14:23

David Carlisle

757,742

score 2 · Answer 2 · answered Jul 28 '22 at 20:49

It's not difficult to make alphabeta to do its job also for XeLaTeX or LuaLaTeX.

\documentclass{article}
\usepackage{iftex}
\usepackage{amsmath}
\iftutex
\newcommand\DeclareUnicodeCharacter[2]{%
  \begingroup\lccode`~="#1\lowercase{\endgroup\protected\def~}{#2}%
  \catcode"#1=\active
}
\fi
\usepackage{alphabeta}
\begin{document}
$α+β+γ=\alpha+\beta+\gamma$
\end{document}

Explanation: the package redefines \alpha to be \TextOrMath{\textalpha}{\mathalpha}, where \mathalpha is the original \alpha. The same for all other Greek letters.

After that it does

\DeclareUnicodeCharacter{03B1}{\alpha}

in order to allow the user to type α to get an alpha in text or math mode. The code between \iftutex (which is true when using XeLaTeX or LuaLaTeX and false otherwise) makes the Greek letter α active and provides a definition for them, which is exactly \alpha as redefine by alphabeta as mentioned above.

Of course, in order to use the Greek letters in text mode, you need a font that supports them.

If you plan to only use XeLaTeX or LuaLaTeX, you can obviously omit \iftutex and \fi.

Greek directly in math mode XeLaTeX instead of PdfLatex

2 Answers2