我注意到，当我从 Computer Modern 切换到 Latin Modern 时，分隔符的大小会发生变化。在 12pt 字体大小的文档中，这会导致内联数学公式\bigl(太大而无法容纳，并扩大该行占用的垂直空间。这在 Computer Modern 中不是问题。这是错误吗？
\documentclass[12pt]{article}
\usepackage{lmodern}
\usepackage{amsmath}
\begin{document}
An equivalence class~$[a]_{\sim} \in A / {\sim}$ consists of all the elements
in $A$ that are mapped to $b = f(a)$. By the axiom of choice, there exists a
choice function~$c \colon A / {\sim} \to A$ which selects a representative
element of each equivalence class. There exists a
function~$h \colon B \to A / {\sim}$, so that
$h(b) = h\bigl(f(a)\bigr) = [a]_{\sim}$. This allows us to construct the
function~$g = c \circ h$, which is in fact a right-inverse of $f$.
\[
\Biggl(\biggl(\Bigl(\bigl((X)\bigr)\Bigr)\biggr)\Biggr)
\]
\end{document}
计算机现代：
拉丁现代：
拉丁现代文格中第四行上方有一个间隙，而计算机现代文格中没有这个间隙。
编辑：
这个帖子egreg 解决了同样的问题。
答案1
由于历史原因，可缩放分隔符使用固定大小，即使对于 cm 来说这显然不是一个好主意（参见exscale包装），但在这里它根本不好，如果您以自然缩放大小使用字体那么......
\documentclass[12pt]{article}
\DeclareFontFamily{OMX}{lmex}{}
\DeclareFontShape{OMX}{lmex}{m}{n}{%
<->lmex10%
}{}
\usepackage{lmodern}
\usepackage{amsmath}
\begin{document}
\show\big
\showthe\baselineskip
\setbox0\hbox{$\big($}\showthe\dimexpr\ht0+\dp0
\showoutput
\showbox0
An equivalence class~$[a]_{\sim} \in A / {\sim}$ consists of all the elements
in $A$ that are mapped to $b = f(a)$. By the axiom of choice, there exists a
choice function~$c \colon A / {\sim} \to A$ which selects a representative
element of each equivalence class. There exists a
function~$h \colon B \to A / {\sim}$, so that
$h(b) = h\bigl(f(a)\bigr) = [a]_{\sim}$. This allows us to construct the
function~$g = c \circ h$, which is in fact a right-inverse of $f$.
\[
\Biggl(\biggl(\Bigl(\bigl((X)\bigr)\Bigr)\biggr)\Biggr)
\]
\end{document}
现在尺寸显示为
> 14.5pt.
l.17 \showthe\baselineskip
?
> 14.40013pt.
略\big少于\baselineskip
您可以重新定义\big尺寸并将其保持在范围内\baselineskip，从而避免\lineskip在段落内使用粘连。
\documentclass[12pt]{article}
\usepackage{lmodern}
\usepackage{amsmath}
\begin{document}
\makeatletter
\renewcommand{\big}{\bBigg@{0.92}}
\makeatother
\show\big
\showthe\baselineskip
\setbox0\hbox{$\big($}\showthe\dimexpr\ht0+\dp0
\showoutput
An equivalence class~$[a]_{\sim} \in A / {\sim}$ consists of all the elements
in $A$ that are mapped to $b = f(a)$. By the axiom of choice, there exists a
choice function~$c \colon A / {\sim} \to A$ which selects a representative
element of each equivalence class. There exists a
function~$h \colon B \to A / {\sim}$, so that
$h(b) = h\bigl(f(a)\bigr) = [a]_{\sim}$. This allows us to construct the
function~$g = c \circ h$, which is in fact a right-inverse of $f$.
\[
\Biggl(\biggl(\Bigl(\bigl((X)\bigr)\Bigr)\biggr)\Biggr)
\]
\end{document}
\show文档顶部显示
> 14.5pt.
l.13 \showthe\baselineskip
?
> 13.24792pt.
<to be read again>
这表明其\big(小于 14.5pt 基线跳高。
.92 是根据经验选择的：.93 使字体跳转到下一个可用大小，但在这里太大了。
答案2
您可以通过强制使用cmex字体来解决问题。我将使用exscale中的类似设置amsfonts。
\documentclass[12pt]{article}
\usepackage{lmodern}
\usepackage{amsmath}
\DeclareFontFamily{OMX}{lmex}{}
\DeclareFontShape{OMX}{lmex}{m}{n}{%
<-7.5>cmex7%
<7.5-8.5>cmex8%
<8.5-9.5>cmex9%
<9.5->cmex10%
}{}%
\begin{document}
% \showoutput
An equivalence class~$[a]_{\sim} \in A / {\sim}$ consists of all the elements
in $A$ that are mapped to $b = f(a)$. By the axiom of choice, there exists a
choice function~$c \colon A / {\sim} \to A$ which selects a representative
element of each equivalence class. There exists a
function~$h \colon B \to A / {\sim}$, so that
$h(b) = h\bigl({f}(a)\bigr) = [a]_{\sim}$. This allows us to construct the
function~$g = c \circ h$, which is in fact a right-inverse of $f$.
\[
\Biggl(\biggl(\Bigl(\bigl((X)\bigr)\Bigr)\biggr)\Biggr)
\]
\end{document}
