LuaLaTeX、ntheorem、unicode-math 和 Libertinus：定理标头加载中的数学计算机现代

Question 1

出现此错误的原因是libertinus加载unicode-math时未设置\mathrm字体\mathversion{bold}。您可以使用\setboldmathrm中的修复此问题fontspec。

\documentclass{article}
\usepackage{libertinus}
\usepackage{ntheorem}

% Enable \mathrm in \mathversion{bold}
\setboldmathrm{Libertinus Serif Bold}[Ligatures=Common, ItalicFont=Libertinus Serif Bold Italic]

% Solely to format the width of a MWE on TeX.SX:
\usepackage[paperwidth=10cm]{geometry}

\theoremstyle{plain}
\theoremheaderfont{\normalfont\bfseries}
\newtheorem{theorem}{Theorem}

\newcommand*{\hybrid}{%
  \symsf{H}^{\mathrm{test\mathhyphen reduction}}_{5}%
}

\begin{document}

This is ok: $\hybrid$

{\bfseries\boldmath This is ok, too: $\hybrid$}

\begin{theorem}[The hybrid $\hybrid$]
The font weight of $\hybrid$ adapts to the header style.
I really like that.

The font is now correctly set to Libertinus Serif Bold.
\end{theorem}

\end{document}

Answer

出现此错误的原因是libertinus加载unicode-math时未设置\mathrm字体\mathversion{bold}。您可以使用\setboldmathrm中的修复此问题fontspec。

\documentclass{article}
\usepackage{libertinus}
\usepackage{ntheorem}

% Enable \mathrm in \mathversion{bold}
\setboldmathrm{Libertinus Serif Bold}[Ligatures=Common, ItalicFont=Libertinus Serif Bold Italic]

% Solely to format the width of a MWE on TeX.SX:
\usepackage[paperwidth=10cm]{geometry}

\theoremstyle{plain}
\theoremheaderfont{\normalfont\bfseries}
\newtheorem{theorem}{Theorem}

\newcommand*{\hybrid}{%
  \symsf{H}^{\mathrm{test\mathhyphen reduction}}_{5}%
}

\begin{document}

This is ok: $\hybrid$

{\bfseries\boldmath This is ok, too: $\hybrid$}

\begin{theorem}[The hybrid $\hybrid$]
The font weight of $\hybrid$ adapts to the header style.
I really like that.

The font is now correctly set to Libertinus Serif Bold.
\end{theorem}

\end{document}

Question 2

使用当前的 LaTeX，文档会产生错误

! LaTeX Error: Math alphabet identifier \mathrm is undefined in math version bold

后任何错误 PDF 输出不是为了使用，而只是可能有助于调试。

对于旧版本，您会收到很多警告而不是错误，但问题本质上是相同的。

ntheorem假设您已\boldmath设置，但没有设置粗体。如果您添加

  \let\boldmath\relax

那么就不会使用粗体数学，也不会出现任何错误，并且文档中使用的字体是：

name                                 type              encoding         emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
MMNMPW+LibertinusSerif-Regular       CID Type 0C       Identity-H       yes yes yes      4  0
EXEWQA+LibertinusMath-Regular        CID Type 0C       Identity-H       yes yes yes      5  0
ACNUSM+LibertinusSerif-Regular       CID Type 0C       Identity-H       yes yes yes      6  0
UJTLVL+LibertinusMath-Regular        CID Type 0C       Identity-H       yes yes yes      7  0
EGXLNF+LibertinusSerif-Bold          CID Type 0C       Identity-H       yes yes yes      8  0
NFIGQN+LibertinusSerif-Italic        CID Type 0C       Identity-H       yes yes yes      9  0

Answer