使用下面非常简单的 LaTeX 文档，名为test.tex：
\documentclass{scrartcl}
\begin{document}
\title{(Title)}
\subtitle{(Subtitle)}
\author{(Author)}
\maketitle
\end{document}
运行时latex test.tex，我在日志文件中收到如下错误报告：
This is pdfTeXk, Version 3.141592-1.40.3 (Web2C 7.5.6)
%&-line parsing enabled.
entering extended mode
(./test.tex
LaTeX2e <2005/12/01>
Babel <v3.8h> and hyphenation patterns for english, usenglishmax, dumylang, noh
yphenation, arabic, basque, bulgarian, coptic, welsh, czech, slovak, german, ng
erman, danish, esperanto, spanish, catalan, galician, estonian, farsi, finnish,
french, greek, monogreek, ancientgreek, croatian, hungarian, interlingua, ibyc
us, indonesian, icelandic, italian, latin, mongolian, dutch, norsk, polish, por
tuguese, pinyin, romanian, russian, slovenian, uppersorbian, serbian, swedish,
turkish, ukenglish, ukrainian, loaded.
(/usr/share/texmf/tex/latex/koma-script/scrartcl.cls
Document Class: scrartcl 2006/07/30 v2.95b KOMA-Script document class (article)
(/usr/share/texmf/tex/latex/koma-script/scrkbase.sty
(/usr/share/texmf/tex/latex/koma-script/scrlfile.sty
Package scrlfile, 2006/03/28 v2.95 KOMA-Script package (loading files)
Copyright (C) Markus Kohm
) (/usr/share/texmf/tex/latex/graphics/keyval.sty))
(/usr/share/texmf/tex/latex/base/size11.clo)
(/usr/share/texmf/tex/latex/koma-script/typearea.sty
Package typearea, 2006/07/30 v2.95b KOMA-Script package (type area)
Copyright (C) Frank Neukam, 1992-1994
Copyright (C) Markus Kohm, 1994-2002
)) (./test.aux)
! Undefined control sequence.
l.6 \subtitle
{(Subtitle)}
?
[1] [2] (./test.aux) )
Output written on test.dvi (2 pages, 484 bytes).
Transcript written on test.log.
为了使其工作，我是否需要定义或包含其他内容？