3

Since when I started LaTeXing I've always wrote the proof environment inside the theorem, but I see many templates or answers in which first the theorem is ended and then the proof is begun.

Namely, what I am used to do is

\documentclass{amsart}
\usepackage{amsthm}% should anyway be loaded by amsart class
\newtheorem{thm}{Theorem}[section]

\begin{document}
\begin{theorem}
Statement of the result
\begin{proof}
Proof of the result
\end{proof}
\end{theorem}
\end{document}

whereas I see most people rather writing

...
\begin{theorem}
Statement of the result
\end{theorem}
\begin{proof}
Proof of the result
\end{proof}
...

I was wondering whether one is a better practice than the other (for spacing/page breaks/references...) or if it is really just a matter of taste.

Thanks in advance

  • 2
    You should post a minimal working example because the actual theorem environments that you are using may be relevant (amsthm, ntheorem, ...). This said, I have always thought that the "correct" usage was to have the proof environment outside of the theorem-like environment. By the KISS principle, it is better not to nest environments unless you need to. – Andrew Jul 13 '17 at 10:12
  • 1
    Thanks @Andrew, I added a MWE. I understand your point, but my thinking is that the proof is part of the theorem, and if, e.g., I define a command inside the theorem it would be reasonable to being able to use it also in the proof, while without nesting it wouldn't be the case, since the command is 'lost' after \end{theorem} – AndreasT Jul 13 '17 at 10:20
  • 4
    The proof environment doesn't belong in the theorem environment. – egreg Jul 13 '17 at 11:08
  • 1
    The theorem environment provides formatting for the statement of the theorem. The proof environment provides the formatting for the proof, which is usually just the "opening" Proof and a symbol that marks the end of the proof. The statement of my theorems are usually in italics, so I definitely don't want to put the proof environment inside the theorem environment. – Andrew Jul 13 '17 at 14:25
  • 2
    @Michael It's very common to have text between the statement and its proof. – egreg Aug 24 '17 at 12:52

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