% This is a sample LaTeX input file.  (Version of 12 August 2004.)
%
% 2011-01-07: Changes by Wolfram Kahl
%   * Name changed to *.ltx (default main document suffix since LaTeX2e)
%   * \usepackage{geometry} added;
%   * Source layout improved, after initial whitespace discussion.
%
% A '%' character causes TeX to ignore all remaining text on the line,
% and is used for comments like this one.

\documentclass{article}      % Specifies the document class

% The geometry package is used to define
% how much of the page is occupied by text.
\usepackage[margin=1.5in]{geometry}

                             % The preamble begins here.
\title{An Example Document}  % Declares the document's title.
\author{Leslie Lamport}      % Declares the author's name.
\date{January 21, 1994}      % Deleting this command produces today's date.


\newcommand{\ip}[2]{(#1, #2)}
                             % Defines \ip{arg1}{arg2} to mean
                             % (arg1, arg2).

%\newcommand{\ip}[2]{\langle #1 | #2\rangle}
                             % This is an alternative definition of
                             % \ip that is commented out.

\begin{document}             % End of preamble and beginning of text.

\maketitle                   % Produces the title.

This is an example input file.  Comparing it with
the output it generates can show you how to
produce a simple document of your own.

\section{Ordinary Text}      % Produces section heading.  Lower-level
                             % sections are begun with similar 
                             % \subsection and \subsubsection commands.

The ends  of words and sentences are marked by   spaces.
It  doesn't matter how many 
spaces    you type; one is as good as 100.  The
end of   a line counts as a space.

One   or more   blank lines denote the  end 
of  a paragraph.  

Since any number of consecutive spaces are treated
like a single one, the formatting of the input
file makes no difference to
      \LaTeX,                % The \LaTeX command generates the LaTeX logo.
but it makes a difference to you.
% Up to here, there is, for demonstration,
% lots of superfluous whitespace in the middle of the text.
%
% From now on, no random source spacing any more,
% and conscious line breaks between sentences and sentence parts
% to improve editability.
When you use \LaTeX,
making your input file as easy to read as possible
will be a great help as you write your document and when you change it.
This sample file shows how you can add comments to your own input file.

Because printing is different from typewriting,
there are a number of things that you have to do differently
when preparing an input file
than if you were just typing the document directly.
Quotation marks like
       ``this'' 
have to be handled specially,
as do quotes within quotes:
       ``\,`this'            % \, separates the double and single quote.
        is what I just 
        wrote, not  `that'\,''.  

Dashes come in three sizes: an 
       intra-word 
dash, a medium dash for number ranges like 
       1--2, 
and a punctuation 
       dash---like 
this.

A sentence-ending space
should be larger than the space between words within a sentence.
You sometimes have to type special commands in
conjunction with punctuation characters to get
this right, as in the following sentence.
       Gnats, gnus, etc.\ all  % `\ ' makes an inter-word space.
       begin with G\@.         % \@ marks end-of-sentence punctuation.
You should check the spaces after periods when reading your output
to make sure you haven't forgotten any special cases.
Generating an ellipsis
       \ldots\               % `\ ' is needed after `\ldots' because TeX 
                             % ignores spaces after command names like \ldots 
                             % made from \ + letters.
                             %
                             % Note how a `%' character causes TeX to ignore 
                             % the end of the input line, so these blank lines 
                             % do not start a new paragraph.
                             %
with the right spacing around the periods
requires a special command.

\LaTeX\ interprets some common characters as commands,
so you must type special commands to generate them.
These characters include the following:
       \$ \& \% \# \{ and \}.

In printing, text is usually emphasized with an
       \emph{italic}  
type style.  

\begin{em}
   A long segment of text can also be emphasized in this way.
   Text within such a segment can be given \emph{additional} emphasis.
\end{em}

It is sometimes necessary to prevent \LaTeX{} from
breaking a line where it might otherwise do so.
This may be at a space, as between the ``Mr.'' and
``Jones'' in
       ``Mr.~Jones'',        % ~ produces an unbreakable interword space.
or within a word---especially when the word is a
symbol like
       \mbox{\emph{itemnum}} 
that makes little sense when hyphenated across lines.

Footnotes\footnote{This is an example of a footnote.}
pose no problem.

\LaTeX{} is good at typesetting mathematical formulas
like
       \( x-3y + z = 7 \) 
or
       \( a_{1} > x^{2n} + y^{2n} > x' \)
or  
       \( \ip{A}{B} = \sum_{i} a_{i} b_{i} \).
The spaces you type in a formula are ignored.
Remember that a letter like
       $x$                   % $ ... $  and  \( ... \)  are equivalent
is a formula when it denotes a mathematical symbol,
and it should be typed as one.

\section{Displayed Text}

Text is displayed by indenting it from the left margin.
Quotations are commonly displayed.
There are short quotations
\begin{quote}
   This is a short quotation.
   It consists of a single paragraph of text.
   See how it is formatted.
\end{quote}
and longer ones.
\begin{quotation}
   This is a longer quotation.
   It consists of two paragraphs of text,
   neither of which are particularly interesting.

   This is the second paragraph of the quotation.
   It is just as dull as the first paragraph.
\end{quotation}
Another frequently-displayed structure is a list.
The following is an example of an \emph{itemized} list.
\begin{itemize}
   \item This is the first item of an itemized list.
     Each item in the list is marked with a ``tick''.
     You don't have to worry about
     what kind of tick mark is used.

   \item This is the second item of the list.
     It contains another list nested inside it.
     The inner list is an \emph{enumerated} list.
     \begin{enumerate}
        \item This is the first item of an enumerated list
          that is nested within the itemized list.

        \item This is the second item of the inner list.  
          \LaTeX\ allows you to nest lists deeper 
          than you really should.
     \end{enumerate}
     This is the rest of the second item of the outer list.
     It is no more interesting than any other part of the item.
   \item This is the third item of the list.
\end{itemize}
You can even display poetry.
\begin{verse}
   There is an environment 
    for verse \\             % The \\ command separates lines
   Whose features some poets % within a stanza.
   will curse.   

                             % One or more blank lines separate stanzas.

   For instead of making\\
   Them do \emph{all} line breaking, \\
   It allows them to put too many words on a line when they'd rather be 
   forced to be terse.
\end{verse}

Mathematical formulas may also be displayed.
A displayed formula is one-line long;
multiline formulas require special formatting instructions.
\[
    \ip{\Gamma}{\psi'}
  =
    x'' + y^{2} + z_{i}^{n}
\]
Don't start a paragraph with a displayed equation,
nor make one a paragraph by itself.

\end{document}               % End of document.
