投影机的问题：文本卡在某种字体中

Question

我遇到了 ${\mathbf{}}$ 仍然存在的问题，即使我关闭了 $\mathbf$ 标签也是如此。查看我的顾问的模板，我插入了一行代码，它停止了这种情况——但是，尝试切换到黑板粗体时，字体反而变粗了。在我插入顾问的那行代码之前，并没有发生这种情况。我该怎么做才能取消剩余字体的粗体？可能是字体重置之类的操作……

最小（非）工作示例：

%\documentclass{beamer}

% custom definition of \Cal, to use variations of symbols not readily available in other pkgs
% see below for printscreen at bottom of post illustrating one of the differences.
\newfam\calfam
\font\bbbten=msbm10
\font\bbbseven=msbm7
\font\bbbfive=msbm5
\font\calten=eusm10
\font\calseven=eusm7
\font\calfive=eusm5
\textfont\calfam=\calten
\scriptfont\calfam=\calseven
\scriptscriptfont\calfam=\calfive
\def\Cal{\fam=\calfam}

% moving the next line to the top of the file results in a third type of font stuck-ing
\documentclass{beamer}

% advisor's line; try compiling with and without it, to see the different problems
\usefonttheme[stillsansserifsmall,stillsansseriflarge]{serif}

\begin{document}
\begin{frame}
$\mathbb Q$ {\textbf{gen}} $\mathbb Q$ ${\mathbf{gen}}$ $\mathbb Q$ $asdf$

$\backslash$Cal O: $\Cal O$; $\backslash$mathcal O: $\mathcal O$
\end{frame}
\end{document}

注意：仅详细说明我的文件顶部的单行注释：使用\mathcal不同字体的 O 会导致这种情况，这对于我正在做的事情来说是不可接受的：

Answer 1

这似乎产生了您要求的结果：

\documentclass{beamer}

% advisor's line; try compiling with and without it, to see the different problems
\usefonttheme[stillsansserifsmall,stillsansseriflarge]{serif}

\usepackage{amsfonts}
\usepackage[mathscr]{eucal}

\begin{document}
\begin{frame}
$\mathbb Q$ {\textbf{gen}} $\mathbb Q$ ${\mathbf{gen}}$ $\mathbb Q$ $asdf$

\texttt{\char`\\mathcal\{O\}}: $\mathcal{O}$

\texttt{\char`\\mathscr\{O\}}: $\mathscr{O}$
\end{frame}
\end{document}