[Tex/LaTex] Transitioning to mathtools – environment proof undefined

amsthmmathtoolstheorems

I am new to LaTeX and I was using the amsthm package in order to write proofs by using the proof environment:

\documentclass{book}
\usepackage{amsthm}
\newtheorem{theorem}{Theorem}

\begin{document}

\begin{theorem}
Stuff in here
\end{theorem}
\begin{proof}
Proof in here
\end{proof}

\end{document}

I then decided to use the mathtools package, since it contains more symbols and corrects some of the amsthm's bugs. However, if I substitute the line

\usepackage{amsthm}

for

\usepackage{mathtools}

I get the error "! LaTeX Error: Environment proof undefined."

Is there a way to correct this?
Thanks for helping!

Best Answer

amsthm and mathtools are unrelated. mathtools updates and extends amsmath.

you still need amsthm if you want the proof environment.

Related Solutions

[Tex/LaTex] Using docmute to import separate document as part of proof

Your MWE works for me with the current version 1.2 of docmute (it fails with the older version 1.1). Maybe updating the package is all you need.

[Tex/LaTex] Using amsthm but still getting “Environment theorem undefined”

This is a more proper way to do it:

\documentclass[a4paper,12pt]{article}

\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage{amssymb,amsmath,amsthm}

\newtheorem{theorem}{Theorem}

\usepackage{mathtools} % Bonus
\DeclarePairedDelimiter\norm\lVert\rVert

\begin{document}

\section{Mathematical Methods}
\begin{theorem}[Placheral's Theorem]
  \begin{equation*}
\norm{ F }^2_2 =2\pi \norm{ u }^2_2 .
\end{equation*}
\end{theorem}
\end{document}

As one might have guessed \newtheorem constructs theorem environments. Use it to define your Theorem, Lemma, etc. environments. You might want to have a look at \theoremstyle as well. Here is a handy method for defining an example env which is not italic.

\theoremstyle{definition} % amsthm only
\newtheorem{example}{Example}

As tohecz mentions, you may want to read up on this subject. Details for amsthm, can be found in amsthdoc.pdf.

The \newtheorem syntax should be covered by any standard LaTeX introduction.

Best Answer

Related Solutions

[Tex/LaTex] Using docmute to import separate document as part of proof

[Tex/LaTex] Using amsthm but still getting “Environment theorem undefined”

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