Use the beta variant

Is it possible to use the curled beta: ϐ (U+03D0) in a formula?

There are variants available for \epsilon, \theta, \phi, \rho, \sigma and \phi with \varepsilon, \vartheta, etc... but there is no \varbeta. Why is that?

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It should be noted that DeTeXify does not produce a result for a decently accurate rendition of this symbol, and it is not included in symbols-a4. –  Sean Allred Jul 16 at 15:49
Welcome to TeX.SX! –  mvkorpel Jul 16 at 15:58
There is a ϐ and a ϰ at least in MinionPro (and probably MyriadPro). –  Bernard Jul 16 at 16:13
There is no variant beta in the standard Computer Modern fonts. I know of no TeX math font providing it. Some OpenType ones do; for usage with unicode-math Asana Math, Latin Modern Math and XITS Math. –  egreg Jul 16 at 16:20
I'd add that usage of \varphi and \phi with different meanings is disputable; the same for the other pairs. They are just stylistic variants. –  egreg Jul 16 at 16:30

4 Answers

You can with XeLaTeX and the mathspec package:

\documentclass{article}
\usepackage{mathspec}
\setmathfont(Greek){Cambria Math}

\begin{document}
$\alpha^2 + \varbeta^2 =\gamma^2$
\end{document}


Here Cambria Math can be replaced by any font on your filesystem that supports this character. Fileformat.info has a list of all known fonts supporting it and a list of locally installed fonts that support it.

As egreg notes, you can also do it with the unicode-math package:

\documentclass{standalone}
\usepackage{unicode-math}
\setmathfont[math-style=TeX]{Cambria Math}
\newcommand{\varbeta}{ϐ}
\begin{document}
$\alpha^2 + \varbeta^2 =\gamma^2$
\end{document}

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mathspec is not compatible with LuaLaTeX. –  mvkorpel Jul 16 at 16:18
Oops! I assumed it was since fontspec is. I've edited. –  Matthew Leingang Jul 16 at 16:31
As far as I know, Cambria Math is suitable for usage with unicode-math; mathspec is mostly a collection of hacks, not really recommended for math intensive documents. –  egreg Jul 16 at 16:32
@egreg: Good to know. I've been using mathspec for years and run into some bugs but I didn't realize it wasn't ready for prime time. I've included a unicode-math implementation. –  Matthew Leingang Jul 16 at 16:42
Thanks. Too bad Computer Modern doesn't support it, I'm allergic to Cambria. I'll try with Arial or Minion Pro –  z̫͋ Jul 16 at 17:22

1. Go to this side and check which fonts on your system provide this symbol.

2. Try including them like below and choose the one, you like most:

% arara: lualatex

\documentclass{article}
\usepackage{unicode-math}

\begin{document}
Asana Math:
\setmathfont{Asana Math}
$\symbol{"003D0}$

XITS Math:
\setmathfont{XITS Math}
$\symbol{"003D0}$

Linux Libertine O:
\setmathfont{Linux Libertine O}
$\symbol{"003D0}$

FreeMono:
\setmathfont{FreeMono}
$\symbol{"003D0}$

FreeSerif:
\setmathfont{FreeSerif}
$\symbol{"003D0}$

DejaVu Serif:
\setmathfont{DejaVu Serif}
$\symbol{"003D0}$
\end{document}


3. Define the symbol in the font you liked most and use it e.g. like this:

% arara: lualatex

\documentclass{article}
\usepackage{unicode-math}
\usepackage{mathtools}
\setmathfont{Latin Modern Math}
\setmathfont[range="03D0]{XITS Math}

%\show\varbeta
\newcommand{\varbeta}{\ensuremath{\symbol{"03D0}}}

\begin{document}
In the next formula I will use \verb+\varbeta+ which yields \varbeta{} in text, inline math ($\varbeta \neq \beta$) and display math
\begin{align*}
\varbeta + \vartheta &= \varepsilon\\
\beta + \theta &= \epsilon
\end{align*}
\end{document}


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I'm not sure if this is straightforward, but after picking the symbol from other font you need to load another range=… from the original font, so that all the dimensions are taken correctly, here, for instance \setmathfont[range=\sum]{Latin Modern Math}. –  Manuel Jul 16 at 18:29
This is really not that cool. Will think about that when I have time. For \setmainfont{} in fontspec it's possible to do that locally. Why not here? Maybe I do a feature request. –  LaRiFaRi Jul 17 at 14:03
Step 2 doesn't seem that necessary since the link at Step 1 shows the beta in each of the locally installed fonts. –  Matthew Leingang Jul 17 at 16:45

With the MinionPro package.

\documentclass{scrartcl}
\usepackage{MinionPro}
\begin{document}
$\epsilon\varepsilon\phi\varphi\theta\vartheta\kappa\varkappa\varbeta\beta$
\end{document}


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You can have them with the MinionPro package, and (PDF)LaTeX both in usual and in French style:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{MinionPro}

\begin{document}

$\varbeta^{2} + \varkappa^{2} = \upvarbeta^{2} + \upvarkappa^{2}$%

\end{document}


The same is probably true with MyriadPro. Not tested, though, as it requires some job from the user. One has to make the pfb's and the tfm's from the Opentype fonts that come with Adobe Reader.

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