forcing a page break in the middle of a long footnote in LaTeX

Question

My supervisor has a LaTeX page that has a small amount of body text and a long footnote consisting of two paragraphs. Is there any way to force the footnote to break across two pages and to choose the break point to be between the two paragraphs.

I did some google searches related to this and most people seemed to have the opposite problem; they didn’t want a long footnote to be broken across two pages.

But from one google result, it might help to put

\interfootnotelinepenalty=0

in the preamble. But that doesn’t solve the problem of choosing the break point to be between the two paragraphs.

Answer 1

In all probability, Ulrike’s answer is what you really want. However, in order to do literally what your question asks for, that is, to force a page break between two paragraphs of a footnote (for example, because you don’t want the footnote to take up so much vertical space on that particular page), you should simply write

\vspace{\maxdimen}

between the two paragraphs in question. The two methods (Ulrike’s and this one) can also be combined:

% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly 
                                 % declare the paper format.

\usepackage[T1]{fontenc}         % Not always necessary, but recommended.
% End of standard header.  What follows pertains to the problem at hand.

\usepackage{lipsum}



\begin{document}

Blah blah.\footnote{\interlinepenalty = 10000
\lipsum[1-2]

\vspace{\maxdimen}

\lipsum[3-4]
}

\end{document}

Note that replacing

\vspace{\maxdimen}

with

\pagebreak[4]

is not guaranteed to work in every situation, not even if you use

\par \penalty -1000000000

in lieu of \pagebreak[4]. The reason is explained on p. 123 of The TeXbook: whenever Step 3 applies, Step 4 is not even tried.

More generally, you could force a page break after a certain line in a footnote by placing

\vadjust{\vskip\maxdimen}

somewhere on that line; this will overcome any other setting that might be in force. For example:

% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly 
                                 % declare the paper format.

\usepackage[T1]{fontenc}         % Not always necessary, but recommended.
% End of standard header.  What follows pertains to the problem at hand.

\usepackage{lipsum}



\begin{document}

Blah blah.\footnote{\interlinepenalty = 10000 \clubpenalty = 10000
\lipsum[1-2]

I~want this footnote to be broken across pages right after the line that
contains \emph{this}\vadjust{\vskip\maxdimen} word.  \lipsum*[3]

\lipsum[4]
}

\end{document}

Finally, it should be noted that, if the problem is that you want to limit the vertical space on a page devoted to footnotes, you can do so by setting the value of a length that can be named as \dimen\footins. For example,

% My standard header for TeX.SX answers:
\documentclass[a4paper]{article} % To avoid confusion, let us explicitly 
                                 % declare the paper format.

\usepackage[T1]{fontenc}         % Not always necessary, but recommended.
% End of standard header.  What follows pertains to the problem at hand.

\usepackage{lipsum}



\begin{document}

\setlength{\dimen\footins}{200pt}

Blah blah.\footnote{\lipsum[1-4]}

\end{document}

Answer 2

You can set \interlinepenalty10000 in the footnote:

\documentclass{article}

\usepackage{lipsum}

\begin{document}
\vspace*{10cm}
blalbl\footnote{\interlinepenalty10000 \lipsum[1]\lipsum[1]\lipsum[1]\lipsum[1]}
\end{document}