# Type Greek letters in Math Mode using Greek keyboard

I know that in order to type Greek letters in my equations I can use \alpha, \beta, etc. However, since I have a Greek keyboard, I would like to be able to write Greek characters right away α ,β, etc., which are just as easy as writing Latin ones. Is it possible? Do I have to redefine \alpha as α (how?), or is there a package to do that for me?

EDIT I'm also writing my text in Greek.

• Do you want to use α also outside math? – Ulrike Fischer Oct 15 '17 at 15:55
• Yes I'm typing text in Greek. – Dimitris Oct 15 '17 at 15:56

An answer for XeLaTeX (what I use sometimes). It can be also used in LaTeX but my MWE is for XeLaTeX:

% !TEX TS-program = XeLaTeX
% !TeX program = xelatex
\documentclass[a4paper,10pt]{article}

\usepackage{xltxtra}

\usepackage{polyglossia}
\setmainlanguage{greek}
\setotherlanguage{english}
\setmainfont[Mapping=tex-text]{Linux Libertine O}
% \setsansfont[Mapping=tex-text]{DejaVu Sans}
% \setmonofont[Mapping=tex-text]{DejaVu Sans Mono}

\newfontfamily\greekfont{Linux Libertine O}
\title{Τίτλος Άρθρου}
\author{Όνομα Επώνυμο}
\date{}

% ΓΙΑ ΕΛΛΗΝΙΚΑ ΣΤΑ ΜΑΘΗΜΑΤΙΚΑ
%Μικρά ελληνικά
\def\α{\alpha}
\def\β{\beta}
\def\γ{\gamma}
\def\δ{\delta}
\def\ε{\epsilon}
\def\ζ{\zeta}
\def\η{\eta}
\def\θ{\theta}
\def\ι{\iota}
\def\κ{\kappa}
\def\λ{\lambda}
\def\μ{\mu}
\def\ν{\nu}
\def\ξ{\xi}
\def\ο{o}
\def\π{\pi}
\def\ρ{\rho}
\def\σ{\sigma}
\def\τ{\tau}
\def\υ{\upsilon}
\def\φ{\varphi}
\def\χ{\chi}
\def\ψ{\psi}
\def\ω{\omega}
\def\ς{\varsigma}
\def\ά{\varalpha}

% Κεφαλαία Ελληνικά
\def\Α{\Alpha}
\def\Β{\Beta}
\def\Γ{\Gamma}
\def\Δ{\Delta}
\def\Ε{\Epsilon}
\def\Ζ{\Zeta}
\def\Η{\Eta}
\def\Θ{\Theta}
\def\Ι{\Iota}
\def\Κ{\Kappa}
\def\Λ{\Lambda}
\def\Μ{\Mu}
\def\Ν{\Nu}
\def\Ξ{\Xi}
\def\Ο{O}
\def\Π{\Pi}
\def\Ρ{\Rho}
\def\Σ{\Sigma}
\def\Τ{\Tau}
\def\Υ{\Ipsilon}
\def\Φ{\Phi}
\def\Χ{X}
\def\Ψ{\Psi}
\def\Ω{\Omega}
%ΤΕΛΟΣ ΓΙΑ ΕΛΛΗΝΙΚΑ ΣΤΑ ΜΑΘΗΜΑΤΙΚΑ

\begin{document}
\maketitle

\section{Ενότητα με μαθηματικά}

$f(x)=\α\cdot \ψ+\ο$

\begin{english}
Text here more than a line that I hope it will be hyphenated if I add a BigEnglishWord
\end{english}

Ελληνικά που θα χρησιμοποιηθούν σαν βασικό κείμενο και θα έχουν τη δυνατότητα να κόβονται οι λέξεις

\end{document}


Output:

Edit: For another solution with XeLaTeX which uses our font in math to, take a look here: https://tex.stackexchange.com/a/396530/120578

Edit: And a LaTeX solution here without any definitions here:

\documentclass[a4paper,10pt]{article}
\usepackage[utf8]{inputenc}
\usepackage[english,greek]{babel}
\usepackage{alphabeta}

\usepackage[LGR, T1]{fontenc}

\title{Τίτλος Άρθρου}
\author{Όνομα Επώνυμο}
\date{}

\begin{document}
\maketitle

\section{Ενότητα με μαθηματικά}

$f(x)=a\cdot f+φ$

\begin{otherlanguage}{english}Text here more than a line that I hope it will be hyphenated if I add BigEnglishWord
\end{otherlanguage}

Ελληνικά που θα χρησιμοποιηθούν σαν βασικό κείμενο και θα έχουν τη δυνατότητα να κόβονται οι λέξεις

\end{document}


Source: https://www.sharelatex.com/learn/Greek (Please inform me if I need to add something because of sharelatex license... I can not find it there.)

Output:

• I'm getting this error ! Undefined control sequence. <argument> \LaTeX3 error: Erroneous variable \c__fontspec_shape_n_n_tl used! l.3806 \emfontdeclare{ \emshape, \eminnershape } (In the file fontspec-xetex.sty) – Dimitris Oct 15 '17 at 17:22
• Try with XeLaTeX... It needs XeLaTeX... not pdflatex (If you want a pdflatex example just ask me to include it) – koleygr Oct 15 '17 at 17:38
• I used XeLaTeX and got that error. No matter what I try to compile, if I choose to do it with XeLaTeX it gives me this error. I have MikTeX and Texmaker.As for pdflatex I made it work with what @Ulrike Fischer said, but if you can suggest how to do it without having to declare everything 1-1 feel free to tell me. – Dimitris Oct 15 '17 at 18:02
• @Dimitris I asked here :tex.stackexchange.com/q/396348/120578. Your problem is probably general with XeLaTeX and has to do with mac or windows... I will inform you if I get an answer that solves your problem. – koleygr Oct 15 '17 at 19:26
• @Dimitris The error probably means that your system is not up-to-date. Run the update manager in user mode and admin mode. – Ulrike Fischer Oct 15 '17 at 19:31

Assuming that you are using pdflatex:

You can define the α so that it tests for math mode. But as the array in the example shows there are places where the test fails. Adding \relax before the \ifmmode would solve this, but destroy kerning in text mode. So a better solution would be a robust definition of α (David Carlisle could say more about this). You can get all the numbers from lgrenc.dfu.

\documentclass[]{article}

\usepackage[LGR]{fontenc}
\usepackage[utf8]{inputenc}

\DeclareUnicodeCharacter{03B1}{\ifmmode\alpha\else\textalpha\fi} % α
\DeclareUnicodeCharacter{03B2}{\ifmmode\beta\else\textbeta\fi}   % β

\begin{document}
α β

$α = β$

$\begin{array}{cc} α α & β β\\ \end{array}$
\end{document}


## Edit

The rather new command \TextOrMath (it works from texlive 2015 on and is also used by the alphabeta package in koleygr's answer) actually avoids both problems so it (and the alphabeta package) is the better alternative to the primitive \ifmmode:

\documentclass[]{article}

\usepackage[LGR]{fontenc}
\usepackage[utf8]{inputenc}

\DeclareUnicodeCharacter{03B1}{\TextOrMath{\textalpha}{\alpha}} % α
\DeclareUnicodeCharacter{03B2}{\TextOrMath{\textbeta}{\beta}}   % β

\begin{document}
α β

$α = β$

$\begin{array}{cc} α α & β β\\ \end{array}$
\end{document}


If it doesn't clash with any other packages you load, you could use the following:

\documentclass[]{article}

\usepackage[mathletters]{ucs}
\usepackage[utf8x]{inputenc}

\begin{document}
$ω$ is prettier than $δ$
\end{document}


If the above clashes (and you use \usepackage[utf8]{inputenc}) you might as well set up the characters manually (which might be a bit of work):

\documentclass[]{article}

\usepackage[utf8]{inputenc}
\DeclareUnicodeCharacter{3C9}{\omega}% I don't want to do this for each greek character
\DeclareUnicodeCharacter{3B4}{\delta}% I don't want to do this for each greek character

\begin{document}
$ω$ is prettier than $δ$
\end{document}


Another (dirty) option using \usepackage[utf8x]{inputenc} would be

\documentclass[]{article}

\usepackage[utf8x]{inputenc}
\let\textomega\omega% dirty
\let\textdelta\delta% dirty

\begin{document}
$ω$ is prettier than $δ$
\end{document}

• It does clash, anything I can do about it? – Dimitris Oct 15 '17 at 15:10
• @Dimitris does \usepackage[utf8x]{inputenc} alone clash? – Skillmon likes topanswers.xyz Oct 15 '17 at 15:14
• No it doesn't clash. – Dimitris Oct 15 '17 at 15:15
• @Dimitris you have to use \usepackage[mathletters]{ucs} prior to \usepackage[utf8x]{inputenc}, did you comply with this? – Skillmon likes topanswers.xyz Oct 15 '17 at 15:24
• I had not. Now that I used it like this it does work, however it messes with my fonts, it doesn't look right. – Dimitris Oct 15 '17 at 15:34