The \newtheorem command is used to create environments for mathematical theorems, definitions etc. that will be formatted and numbered in a consistent style.
Syntax[]
The command can be used in three distinct ways:
\newtheorem{env_name}{title}
\newtheorem{env_name}{title}[numbered_within]
\newtheorem{env_name}[numbered_like]{title}
This defines a new environment env_name that will be labeled with title. If the optional parameter numbered_within is given, the environment's counter will be subordinate to the existing counter numbered_within, e.g. "chapter" or "section". If instead the optional parameter numbered_like is given, the environment will share the counter of the previously defined theorem-like environment numbered_like.
This command is fragile and is commonly used in the preamble.
Example[]
\newtheorem{lem}{Lemma}
\newtheorem{thm}{Theorem}
\begin{lem}
text of lemma
\end{lem}
The next result follows immediately.
\begin{thm}[Gauss] % puts "Gauss" in parens after theorem head
text of theorem
\end{thm}
See also[]
The amsthm package provides
- a proof environment,
- \newtheorem* to define unnumbered theorem-like environments, and
- \theoremstyle to change the appearance of theorem-like environments.
External links[]
- Theorem on Wikibooks
- Theorems and proofs on Overleaf
- This article includes content from the unofficial LaTeX2e reference manual, which is licensed under the old-style GNU documentation license.