Equivalent of mathbb for lower-case Greek letters (specially gamma)

Question

I'm trying to find a way of writing $\gamma$, and possible other lower-case Greek letters, in a mathbb-like style. What command/package should I use for that?

I tried the solution mentioned in one of the answers of this question but this does not seem to work.

The solution proposed in the accepted answer to this question technically works. But the font is not satisfactory.

So is there a package where the black-board version of a $\gamma$ looks good?

Answer 1

The double struck (blackboard bold) lower case gamma is part of Unicode, as well as the upper case gamma, lower and upper case pi, and upper case sigma (but actually that is the double struck sum symbol, that happens to be a sigma).

If you have a (math) font that defines these characters then you can use them with the unicode-math package with XeLaTeX or LuaLaTeX. Various fonts have a different design for these characters, so you can choose which one you like best.

Code with some examples:

\documentclass{article}
\usepackage{fontspec}
\usepackage{unicode-math}
\begin{document}
\setmathfont{Symbola}
Symbola: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{DejaVu Sans}
DejaVu Sans: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{DejaVu Serif}
DejaVu Serif: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{Code2000-rdLO.ttf}
Code2000: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{STIX}
STIX: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{seguisym.ttf}
Segoe UI Symbol: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{Asana Math}
Asana Math: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{Latin Modern Math}
Latin Modern: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\setmathfont{STIX}[range={\Bbbgamma}]
Latin Modern + STIX: $\mathbb{\Gamma\gamma\Pi\pi\sum}$

\end{document}

This example is largely based on https://www.fileformat.info/info/unicode/char/213d/fontsupport.htm (click 'View All' to see the gamma character in the fonts that I did not include in the code above).

Note that \setmathfont changes the font for all math characters, however you can also set the font for just a single character using the range parameter, as shown in the last example. The codes for the range can be found in the file unicode-math-table.tex.