如何在 LaTeX 中对小节下的定理进行编号？

Question

我想在 LaTeX 中创建章节和小节，同时我需要在章节中将定理数设为 1.1。和 1.2 等。并且，在第一个小节中，我想要定理数为 1.1.1 和 1.1.2。在小节 2 中，我想要定理数为 1.2.1。和 1.2.2。此外，在小节 2 中，我想要添加一些注释和推论，因此我需要将定理数设为 1.2.3 和 1.2.4。我该怎么办？

Answer 1

您可以使用 LaTeX 2ε-kernel 来玩\@addtoreset。

源2e.pdf说：

\@addtoreset{⟨foo⟩}{⟨bar⟩}：添加计数器⟨foo⟩到计数器列表\cl@bar时重置计数器⟨酒吧⟩呈阶梯状。

为了确保放入 .pdf 文件中的目标名称的唯一性，hyperref 包重新定义了\@addtoreset另外的重新定义，以提供以下值：\theH⟨foo⟩⟨酒吧⟩各自。\theH⟨bar⟩

我借了德雷克斯皮皮的定理风格： ：-）

\documentclass[a4paper]{scrartcl}
\usepackage{hyperref}
\usepackage{amsmath}
\usepackage{amsthm}

\newtheoremstyle{break}
{\topsep}{\topsep}%
{\upshape}{}%
{\bfseries}{}%
{\newline}{}%


\theoremstyle{break}
\newtheorem{MyNiceTheorem}{Theorem}[subsection]% Use subsection to ensure uniqueness of destination-names in case of using hyperref.
\AtBeginDocument{%
  % Let's number theorems within sections and subsections
  \def\theMyNiceTheorem{\ifnum\value{subsection}<1 \thesection\else\thesubsection\fi.\arabic{MyNiceTheorem}}%
  \csname @addtoreset\endcsname{MyNiceTheorem}{section}%
  \csname @addtoreset\endcsname{MyNiceTheorem}{subsection}% <- Do this \@addtoreset as the last one to ensure uniqueness of destination-names in case of using hyperref.
}%

\newtheorem{MyNiceRemark}[MyNiceTheorem]{Remark}
\newtheorem{MyNiceCorollary}[MyNiceTheorem]{Corollary}


\begin{document}
    
    \noindent Cross-referencing:

    \verb|\ref{FirstSectionTheorem}|: \ref{FirstSectionTheorem}

    \verb|\ref{FirstSubSectionTheorem}|: \ref{FirstSubSectionTheorem}

    \verb|\ref{SecondSubSectionTheorem1}|: \ref{SecondSubSectionTheorem1}

    \verb|\ref{SecondSubSectionTheorem2}|: \ref{SecondSubSectionTheorem2}

    \verb|\ref{SecondSectionTheorem}|: \ref{SecondSectionTheorem}

    \verb|\ref{FirstSectionCorollary}|: \ref{FirstSectionCorollary}

    \verb|\ref{FirstSubSectionCorollary}|: \ref{FirstSubSectionCorollary}

    \verb|\ref{SecondSubSectionCorollary1}|: \ref{SecondSubSectionCorollary1}

    \verb|\ref{SecondSubSectionCorollary2}|: \ref{SecondSubSectionCorollary2}

    \verb|\ref{SecondSectionCorollary}|: \ref{SecondSectionCorollary}

    \verb|\ref{FirstSectionRemark}|: \ref{FirstSectionRemark}

    \verb|\ref{FirstSubSectionRemark}|: \ref{FirstSubSectionRemark}

    \verb|\ref{SecondSubSectionRemark1}|: \ref{SecondSubSectionRemark1}

    \verb|\ref{SecondSubSectionRemark2}|: \ref{SecondSubSectionRemark2}

    \verb|\ref{SecondSectionRemark}|: \ref{SecondSectionRemark}


    \noindent\hrulefill

    \section{first section}
    
    \begin{MyNiceTheorem}\label{FirstSectionTheorem}%
        Theorem in first section
    \end{MyNiceTheorem}

    \begin{MyNiceCorollary}\label{FirstSectionCorollary}%
        Corollary in first section
    \end{MyNiceCorollary}

    \begin{MyNiceRemark}\label{FirstSectionRemark}%
        Remark in first section
    \end{MyNiceRemark}

    
    \subsection{first subsection}
    
    \begin{MyNiceTheorem}\label{FirstSubSectionTheorem}%
        Theorem in first subsection
    \end{MyNiceTheorem}

    \begin{MyNiceCorollary}\label{FirstSubSectionCorollary}%
        Corollary in first subsection
    \end{MyNiceCorollary}

    \begin{MyNiceRemark}\label{FirstSubSectionRemark}%
        Remark in first subsection
    \end{MyNiceRemark}

    
    \subsection{second subsection}
    
    \begin{MyNiceTheorem}\label{SecondSubSectionTheorem1}%
        First theorem in second subsection
    \end{MyNiceTheorem}

    \begin{MyNiceCorollary}\label{SecondSubSectionCorollary1}%
        First corollary in second subsection
    \end{MyNiceCorollary}

    \begin{MyNiceRemark}\label{SecondSubSectionRemark1}%
        First remark in second subsection
    \end{MyNiceRemark}


    \begin{MyNiceTheorem}\label{SecondSubSectionTheorem2}%
        Second theorem in second subsection
    \end{MyNiceTheorem}

    \begin{MyNiceCorollary}\label{SecondSubSectionCorollary2}%
        Second corollary in second subsection
    \end{MyNiceCorollary}

    \begin{MyNiceRemark}\label{SecondSubSectionRemark2}%
        Second remark in second subsection
    \end{MyNiceRemark}


    \section{second section}
    
    \begin{MyNiceTheorem}\label{SecondSectionTheorem}%
        Theorem in second section
    \end{MyNiceTheorem}

    \begin{MyNiceCorollary}\label{SecondSectionCorollary}%
        Corollary in second section
    \end{MyNiceCorollary}

    \begin{MyNiceRemark}\label{SecondSectionRemark}%
        Remark in second section
    \end{MyNiceRemark}


\end{document}

Answer 2

您可以使用两个命令来创建定理，一个用于章节以下的定理，一个用于小节以下的定理，并相应地设置计数器。

\documentclass[a4paper]{scrartcl}
\usepackage{amsmath}
\usepackage{amsthm}

\newtheoremstyle{break}
{\topsep}{\topsep}%
{\upshape}{}%
{\bfseries}{}%
{\newline}{}%

\theoremstyle{break}
\newtheorem{sectheo}{Theorem}[section]
\newtheorem{subsectheo}{Theorem}[subsection]

\begin{document}
    \section{first section}
    
    \begin{sectheo}
        first section theorem
    \end{sectheo}
    
    \subsection{first subsection}
    
    \begin{subsectheo}
        first subsection theorem
    \end{subsectheo}
    
    \subsection{second subsection}
    
    \begin{subsectheo}
        second subsection theorem
    \end{subsectheo}
\end{document}