# Numbering claims

I would like to have the claims in the proof of a given theorem or proposition numbered independently from those in a different theorem or proposition. This question has already been asked here: ntheorem: numbering of claim and its proof. However, I must be doing something wrong as it does not work for me. Typing

\documentclass[11pt]{amsart}

\theoremstyle{plain} \newtheorem{thm}{Theorem}[section] \newtheorem{prop}[thm]{Proposition} \newtheorem{claim}[thm]{Claim}

\begin{document}

\section{blah}

\begin{thm}
\begin{claim}
\end{claim}
\end{thm}

\begin{prop}
\begin{claim}
\end{claim}
\end{prop}

\end{document}


does not number claims within the theorem or proposition they refer to but sequentially to them. I tried also with \usepackage[thmmarks]{ntheorem}, but it gives me an error:

(Package ntheorem Error: Theorem style plain already defined.)

What am I doing wrong?

• Well, you're using the amsart class which defines many features ntheorem wants to provide as well -- and this must conflict. It is stated in the documentation of ntheorem, that amsthm shouldn't be used with ntheorem, the same is true for amsart – user31729 Feb 17 '17 at 18:49
• Since you have some responses below that seem to answer your question, please consider marking one of them as ‘Accepted’ by clicking on the tickmark below their vote count (see How do you accept an answer?). This shows which answer helped you most, and it assigns reputation points to the author of the answer (and to you!). It's part of this site's idea to identify good questions and answers through upvotes and acceptance of answers. – user36296 Jul 2 '18 at 19:36

You are getting what you have asked for: claims numbered in the same sequence as theorems and propositions. If you want claims to be numbered within them, instead, you must replace

\newtheorem{claim}[thm]{Claim}


with

\newtheorem{claim}{Claim}[thm]


Here’s a MWE:

\documentclass[a4paper]{amsart}
\usepackage[T1]{fontenc} % unrelated to your question, but I'd recommend it

\theoremstyle{plain}
\newtheorem{thm}{Theorem}[section]
\newtheorem{prop}[thm]{Proposition}
\newtheorem{claim}{Claim}[thm]

\begin{document}

\section{Blah}

\begin{thm}
Statement of theorem.
\begin{claim}
Statement of claim.
\end{claim}
More text.
\begin{claim}
Statement of another claim.
\end{claim}
End of theorem.
\end{thm}

\begin{prop}
Statement of proposition.
\begin{claim}
Statement of claim.
\end{claim}
More text.
\begin{claim}
Statement of another claim.
\end{claim}
End of proposition.
\end{prop}

\end{document}


And here’s the output:

• Great! But what is the difference between \newtheorem{claim}[thm]{Claim} and \newtheorem{claim}{Claim}[thm]? I mean, in general. – Tanda Feb 17 '17 at 22:13
• Great, thanks! But what is the difference between \newtheorem{claim}[thm]{Claim} – Tanda Feb 17 '17 at 22:13
• @AlessandraIozzi: It’s explained in the manual of the amsthm package (Using the amsthm Package), section 3 (pp. 5–7). You should be able to display that document by opening a terminal emulator window and typing the command texdoc amsthm. – GuM Feb 18 '17 at 23:21