problem with math font and LuaLaTeX

Question

The following code works fine if compiled in pdflatex:

\documentclass{beamer}
\usepackage{quattrocento}
\begin{document}
\begin{frame}
Quattrocento $30\cdot40$
\end{frame}
\end{document}

As is explained by egreg in my previous question (Getting Quattrocento as math font in article class) beamer automatically uses the text font for letters and numbers in mathmode.

Now I need to compile my presentation with LuaLaTeX, so I changed the code to:

\documentclass{beamer}
\usepackage{fontspec}
\usepackage{unicode-math}
\setsansfont{Quattrocento}
\setmathfont{Quattrocento}
\begin{document}
\begin{frame}
Quattrocento ${30\cdot40}$
\end{frame}
\end{document}

However in this way the \cdot is not printed (I'm assuming because the symbol is not in the Quattrocento font, and now the font is used for all math symbols, not only letters-numbers).

How can I restore beamer behavior with pdflatex when using lualatex?

Answer 1

Quattrocento doesn't qualify as a math font for \setmathfont; fonts for this purpose should be specially tailored for math, with hundreds of symbols and some internal tables.

You can, for limited purposes, use mathastext, but you have also to load fontspec with the no-math option:

\documentclass{beamer}
\usefonttheme{professionalfonts}

\usepackage[no-math]{fontspec}
\usepackage[sfdefault]{quattrocento}
\usepackage[italic]{mathastext}

\begin{document}
\begin{frame}
Quattrocento $30\cdot40+ab-c$           
\end{frame}
\end{document}

Note that ${30\cdot 40}$ is not necessary; adding braces could even be dangerous if not done properly: better remove them.