# Footnote outside theorem environment

I tried to add a footnote in a tcolorbox based theorem environment, which is showing right inside the theorem box. How to position footnote at the bottom of the page?

\documentclass[a4paper]{article}

% ------------------------------------------------------------------------------------------
%                                   Packages Required
% ------------------------------------------------------------------------------------------

\usepackage{amsthm}
\usepackage{tcolorbox}

% ------------------------------------------------------------------------------------------
%                           tcolorbox and theorem Environment
% ------------------------------------------------------------------------------------------

\tcbuselibrary{theorems}
\newtcbtheorem
[]% init options
{theorem}% name
{Theorem}% title
{%
colback=green!5,
colframe=green!35!black,
fonttitle=\bfseries,
}% options
{thm}% prefix

\makeatletter
% ------------------------------------------------------------------------------------------
%                                   User defined Commands
% ------------------------------------------------------------------------------------------

\newcommand{\reals}{\mathbb{R}}
\renewcommand{\qedsymbol}{$\blacksquare$}
\newcommand{\f}[1]{$f(#1)$}
\newcommand{\tcb@cnt@theoremautorefname}{Theorem}
\makeatother

% ------------------------------------------------------------------------------------------

\begin{document}

\begin{theorem}{Cauchy's Theorem}{}
Let C be a simple\footnote{A simple curve is one which does not cross itself.}. closed curve with continously turning tangents except possibly at a finite number of of points (otherwise curve must be smooth). If \f{z} is analytic on and inside C, then
$$\oint_{C} f(z) \, dz = 0$$
\end{theorem}

\end{document}

• See Can I get a normal footnote in a minipage environment in LaTeX? How? Not an exact duplicate but the solution using \footnotemark/\footnotetext is the same. – campa Dec 11 '19 at 12:45
• Unrelated: \f{z} and $f(z)$ differ by one keystroke, and yet I believe the second one is much more clear. (Very personal opinion, of course.) – campa Dec 11 '19 at 12:49
• @campa Yes, but it prevents me from keep pressing dollar sign for inline formulas. In that case it's much quicker when you write math. – 147875 Dec 11 '19 at 12:54
• It might be faster to type, but now your missing the clear separation between text and math in your code. So I agree with campa, not recommendable. – daleif Dec 11 '19 at 17:39
• Thank you @daleif, I'll make sure I won't repeat again. Is there any package or tips that would help me in faster typing the manuscript? – 147875 Dec 12 '19 at 9:53

You can obtain what you want with etoolbox and the footnote package (from the mdwtools bundle):

\documentclass[a4paper]{article}

% ------------------------------------------------------------------------------------------
% Packages Required
% ------------------------------------------------------------------------------------------

\usepackage{amsthm}
\usepackage{tcolorbox}
% ------------------------------------------------------------------------------------------
% tcolorbox and theorem Environment
% ------------------------------------------------------------------------------------------

\tcbuselibrary{theorems}
\newtcbtheorem
[]% init options
{theorem}% name
{Theorem}% title
{%
colback=green!5,
colframe=green!35!black,
fonttitle=\bfseries,
}% options
{thm}% prefix

\makeatletter
% ------------------------------------------------------------------------------------------
% User defined Commands
% ------------------------------------------------------------------------------------------

\newcommand{\reals}{\mathbb{R}}
\renewcommand{\qedsymbol}{$\blacksquare$}
\newcommand{\f}[1]{$f(#1)$}
\newcommand{\tcb@cnt@theoremautorefname}{Theorem}
\makeatother

% ------------------------------------------------------------------------------------------

\usepackage{footnote}
\usepackage{etoolbox}
\BeforeBeginEnvironment{theorem}{\savenotes}
\AfterEndEnvironment{theorem}{\spewnotes}

\begin{document}

\vspace*{13cm}

\begin{theorem}{Cauchy's Theorem}{}
Let C be a simple\footnote{A simple curve is one which does not cross itself.}. closed curve with continously turning tangents except possibly at a finite number of of points (otherwise curve must be smooth). If \f{z} is analytic on and inside C, then
$$\oint_{C} f(z) \, dz = 0$$
\end{theorem}

\end{document}


• What is the purpose of using ∮ instead of \oint, Let C be instead of Let $C$ be , and inside C, instead of and inside $C$, and f(z) \, dz instead of f(z) \, \mathrm{d}z? – Schrödinger's cat Dec 11 '19 at 15:51
• @Schrödinger'scat: For the first point, sorry, I didn't pay attention to what my editor was displaying. It is configured to do some ‘pretty display’, i.e. when it reads \oint, it displays ∮ (but saves the code as \oint). For the other points, I simply copied the code in the O.P., and didn't check whether this code corresponded to the image. – Bernard Dec 11 '19 at 16:46
• @Schrödinger'scat: What's is the difference between $dz$ and $\mathdrm{d}z$, since I don't find much difference between them. Please enlighten me, so that I can write better syntax. Any source for math-texing is fine. – 147875 Dec 12 '19 at 10:06