在撰写论文提交报告时，我将各章分成了单独的.tex文件，但我必须amsthm在各章中使用包。我将包包含在主.tex文件中，但不起作用；我也尝试将包包含在各个章节中，但仍然不起作用。有人可以指导我吗？
在主文件中，我使用命令输入章节
\input{chapters/chapter_1}
我chapter_1.tex必须写出该定理的证明。
我使用了包，main.tex但它在那里不起作用。所以我将包包含在chapter_1.tex（第 1 章文件的名称.tex）中，但显示的消息是“只能在序言中使用”。
主文件
\documentclass[12pt]{report}
\usepackage[utf8]{inputenc}
\title{Sample}
\begin{document}
\maketitle
\input{sample_1}
\end{document}
以下是该章节的代码
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\usepackage{amsthm}
\begin{lemma}
Lemma statement.
\end{lemma}
\begin{proof}
Suppose D is a $(v, k, \lambda)$-difference set. There are $k(k-1)$ ordered
pairs $(r_1, r_2)$, with $r_1$, $r_2$ distinct elements of $D$, and therefore $k(k-1)$ differences $r_1$ - $r_2$ in the multiset $\Delta$. However, since $D$ is a difference set, each of the $v - 1$ non-identity elements of $G$ appears
exactly $\lambda$ times among the elements listed in $\Delta$.
\end{proof}
````
答案1
好吧，让我们首先用给定的代码片段构建一个 MWE：
\documentclass[12pt]{report}
\usepackage[utf8]{inputenc}
\title{Sample}
\begin{document}
\maketitle
%\input{sample_1}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\usepackage{amsthm}
\begin{lemma}
Lemma statement.
\end{lemma}
\begin{proof}
Suppose D is a $(v, k, \lambda)$-difference set. There are $k(k-1)$ ordered
pairs $(r_1, r_2)$, with $r_1$, $r_2$ distinct elements of $D$, and therefore $k(k-1)$ differences $r_1$ - $r_2$ in the multiset $\Delta$. However, since $D$ is a difference set, each of the $v - 1$ non-identity elements of $G$ appears
exactly $\lambda$ times among the elements listed in $\Delta$.
\end{proof}
\end{document}
这导致第一个错误：
! LaTeX Error: Can be used only in preamble.
See the LaTeX manual or LaTeX Companion for explanation.
Type H <return> for immediate help.
...
l.15 \usepackage
{amsthm}
Your command was ignored.
Type I <command> <return> to replace it with another command,
or <return> to continue without it.
正如您在第 15 行中看到的，错误是：命令\usepackage只能在序言中使用。因此，让我们将其移到序言中：
\documentclass[12pt]{report}
\usepackage[utf8]{inputenc}
\usepackage{amsthm}
\title{Sample}
\begin{document}
\maketitle
%\input{sample_1}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\begin{lemma}
Lemma statement.
\end{lemma}
\begin{proof}
Suppose D is a $(v, k, \lambda)$-difference set. There are $k(k-1)$ ordered
pairs $(r_1, r_2)$, with $r_1$, $r_2$ distinct elements of $D$, and therefore $k(k-1)$ differences $r_1$ - $r_2$ in the multiset $\Delta$. However, since $D$ is a difference set, each of the $v - 1$ non-identity elements of $G$ appears
exactly $\lambda$ times among the elements listed in $\Delta$.
\end{proof}
\end{document}
它编译时出现一个警告（正确，没有给出作者！）并且没有错误。
最好将theorem、corollary和的定义移到lema序言中，这样我们就可以在所有章节中使用这些定义……
因此我们得到最终的代码：
\documentclass[12pt]{report}
\usepackage[utf8]{inputenc}
\usepackage{amsthm} % <=================================================
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma} % <==================================
\title{Sample}
\begin{document}
\maketitle
%\input{sample_1}
\begin{lemma}
Lemma statement.
\end{lemma}
\begin{proof}
Suppose D is a $(v, k, \lambda)$-difference set. There are $k(k-1)$ ordered
pairs $(r_1, r_2)$, with $r_1$, $r_2$ distinct elements of $D$, and therefore $k(k-1)$ differences $r_1$ - $r_2$ in the multiset $\Delta$. However, since $D$ is a difference set, each of the $v - 1$ non-identity elements of $G$ appears
exactly $\lambda$ times among the elements listed in $\Delta$.
\end{proof}
\end{document}
得到第二个 pdf 页的结果：
