为什么编译器说抽象环境未定义？

Question

\documentclass [10pt,a4paper]{report}
\usepackage [utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}
\begin{document}

\begin{Abstract}
text here
\end{Abstract}

\end{document}

Answer 1

我相信您正在寻找的环境是abstract。

\documentclass [10pt,a4paper]{report}
\usepackage [utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}
\begin{document}

\begin{abstract}
text here
\end{abstract}

\end{document}

正如 Sean Allred 在他的评论中解释的那样，TeX（因此 LaTeX）是区分大小写。这意味着abstract和Abstract指定两个不同的环境，且后者未定义。

该文档证明LaTeX区分大小写：

\documentclass{article}

\newcommand\mymacro{\LaTeX{} is case-sensitive.}
% Actually, if LaTeX was not case-sensitive, the next line would create an error
% (\newcommand would fail if \MYMACRO were already defined)
\newcommand\MYMACRO{\LaTeX{} is \textit{not} case-sensitive.}

\begin{document}

\mymacro

\end{document}

Answer 2

\documentclass [10pt,a4paper]{report}
\usepackage [utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage[left=2cm,right=2cm,top=2cm,bottom=2cm]{geometry}

\newenvironment{Abstract}
{\begin{abstract}}
{\end{abstract}}

\begin{document}

\begin{Abstract}
text here
\end{Abstract}

\end{document}