脚注中的公式导致下一页的脚注为空

Question

我在标准article文档中有一个脚注，它恰好位于页面底部，并且脚注以环境结尾equation。这导致脚注在下一页继续（我猜这是因为在环境后插入了某种空白equation），即使没有剩余内容可显示。如何避免下一页出现空白脚注？

请参阅 MWE 第 2 页底部：

\documentclass{article}
\usepackage{blindtext}

\begin{document}

\section{Introduction}

\blindtext[4]

Here comes a footnote ending on an equation.\footnote{That's the equation:
\begin{equation}
    a^2 = b^2 + c^2
\end{equation}
}
And here continues the text. As you can see, on the bottom of p.2 there is line from the footnote although the whole footnote is printed on the first page. \blindtext
\end{document}

Answer 1

如果您愿意在底部留出 4pt，则可以将脚注挤压到第 1 页。

\documentclass{article}
\usepackage{blindtext}
\usepackage{showframe}

\begin{document}

\section{Introduction}

\blindtext[4]

Here comes a footnote ending on an equation.\footnote{\raisebox{0pt}[\height][\dimexpr\depth-4pt]{\parbox[t]{\dimexpr \linewidth-\bibindent}%
{\abovedisplayskip=0pt
\belowdisplayskip=0pt
That's the equation:
\begin{equation}
    a^2 = b^2 + c^2
\end{equation}}}}
And here continues the text. As you can see, on the bottom of p.2 there is line from the footnote although the whole footnote is printed on the first page. \blindtext
\end{document}

Answer 2

您可以通过设置惩罚来抑制断点：

\documentclass{article}
\usepackage{blindtext}

\begin{document}

\section{Introduction}

\blindtext[4]

Here comes a footnote ending on an equation.\footnote{That's the equation:
\postdisplaypenalty=10000
\begin{equation}
    a^2 = b^2 + c^2
\end{equation}
}
And here continues the text. As you can see, on the bottom of p.2 there is line from the footnote although the whole footnote is printed on the first page. \blindtext
\end{document}