Ich habe den folgenden Beispielcode:
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[german]{babel}
\usepackage{blindtext}
\usepackage{lmodern}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{dsfont}
\usepackage{mathrsfs}
\usepackage{marvosym}
\usepackage{tabularx}
\usepackage{tabulary}
\usepackage{booktabs}
\usepackage{wasysym}
%\usepackage[a4paper,top=1cm,bottom=2cm,left=2cm,right=2cm]{geometry}
\theoremstyle{remark}
\newtheorem*{remark}{Remark}
\theoremstyle{definition}
\newtheorem{definition}{Definition}[section]
%\newtheorem{theorem}{Theorem}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\title{Theorems And Proofs}
\author{Napoleone Bonaparte}
\date{May 2014}
\renewcommand\qedsymbol{$\blacksquare$}
\begin{document}
\begin{flushleft}
\section{Introduction}
Theorems can easily be defined
\theoremstyle{definition}
\begin{definition}{Fibration}
A fibration is a mapping between two topological spaces that has the homotopy lifting property for every space $X$.
\end{definition}
\begin{theorem}
Let $f$ be a function whose derivative exists in every point, then $f$ is
a continuous function.
\end{theorem}
\begin{theorem}[Pythagorean theorem]
\label{pythagorean}
This is a theorema about right triangles and can be summarised in the next
equation
\[ x^2 + y^2 = z^2 \]
\end{theorem}
And a consequence of theorem \ref{pythagorean} is the statement in the next
corollary.
\begin{corollary}
There's no right rectangle whose sides measure 3cm, 4cm, and 6cm.
\end{corollary}
You can reference theorems such as \ref{pythagorean} when a label is assigned.
\begin{lemma}
Given two line segments whose lengths are $a$ and $b$ respectively there is a
real number $r$ such that $b=ra$.
\end{lemma}
\begin{proof}
To prove it by contradiction try and assume that the statemenet is false,
proceed from there and at some point you will arrive to a contradiction.
\end{proof}
\end{flushleft}
\end{document}
aber ich verstehe es nicht, weil ich Titel, Autor und Datum nicht sehe.
Antwort1
Die Metadaten werden mit dem Befehl in das Dokument eingefügt \maketitle. Normalerweise steht das als erstes nach \begin{document}.