Lesson 3: Text Environments in LaTeX

Environments that create a large character

One type of text environment creates what is sometimes called a "large symbol". For example, you can use the tabular environment to create a table, which is treated by LaTeX as a large symbol and placed somewhere on the page by LaTeX, or "floated". PostScript graphics can also be handled by LaTeX as large symbols.

Below is an example of LaTeX source code that creates a table showing the effects of the basic font-size change declarations (Note how they are used). The table has two columns, with & used as a separator, and the text in each column is left justified, which is done by the template argument { l l } after the \tabular command. Those are two letters "ell", not two numbers "one". The spaces in the argument are ignored.

If you wanted the text in the first column right justified, you could use the template { r l }. If you wanted vertical lines at the sides of the table, you could use the template { |r l |} indicating the position of vertical bars. If you also wanted the two columns separated by a vertical line, then you could use the template { |r | l|} as the argument for \begin{tabular}. You can also center the text in a column by substituting "c" for "r" or "l".

We summarize.

Here is how justification is specified:

• l means that the column will be left justified
• r means that the column will be right justified
• c means that the column will be centered

Here are some layout features:

1. Use the command \hline after \\ to draw a line between rows
2. Type a | in the template wherever you want columns separated by a vertical line segment
3. Type @{.} if you want a period instead of a space between two columns, or substitute any symbol you like in the curly brackets
4. To get a caption, say MY TABLE, underneath your table, put a line with the command \caption{MY TABLE} just before the end{table} line.

LaTeX source code for the table

\begin{table}[ht]
\begin{tabular}{ l l }
\textbf{Declaration}    &  \textbf{Typeset by \LaTeX} \\ \hline
\verb=\tiny=            &  {\tiny sample text}        \\
\verb=scriptsize=       &  {\scriptsize sample text}  \\
\verb=\footnotesize=    &  {\footnotesize sample text}\\
\verb=\small=           &  {\small sample text}       \\
\verb=\normalsize=      &  {\normalsize sample text}  \\
\verb=\large=           &  {\large sample text}       \\
\verb=\Large=           &  {\Large sample text}       \\
\verb=\LARGE=        	&  {\LARGE sample text}       \\
\verb=\huge=        	&  {\huge sample text}        \\
\verb=\Huge=        	&  {\Huge sample text}        \\ \hline
\end{tabular}
     \caption{Font Size Declarations}
\end{table}

The image below is an enlarged version of the typeset table.

Notice:

• The tabular environment is nested inside the table environment, which displays the table created by tabular.
• The optional argument [ht] following the command \begin{table} indicates to LaTeX that we prefer the table to be "floated" either at the top of the page or at the point where where the table appears in the source file (h for here, t for top, b for bottom, p for separate page).
• The command \verb allows us to typeset LaTeX commands instead of having LaTeX interpret them. What follows is a non-letter, such as = or +, then the string that is to be typeset verbatim, then a matching non-letter. Be careful that the string that you want to typeset verbatim does not contain a non-letter that matches the ones you are using to mark the ends of the string. For example \verb+$sin(x)+cos(x)=1$+ will give an error message because LaTeX will interpret the string $sin(x) as what you want typeset verbatim, and will go on to try interpreting cos(x)+1$+ in the usual way. Since LaTeX uses pairs of matching $ signs, it will complain. Best mark the ends of the string by ! instead.

Exercise on Tables

Make a LaTeX document (12pt article class) to display the following table.

Note: The names are left justified and the other entries are right justified.
Use the title line \title{\LaTeX{} Table Exercise.
Hand in a typeset copy.

Proclamations (theorem-like constructs)

To produce nicely formatted theorems, propositions and corollaries, you follow a two step procedure:

Step One:

In the preamble, use a \newtheorem command to define the proclamation. For example,
\newtheorem{theorem}{Theorem}
can be used to define a theorem environment that is used with the commands \begin{theorem} ...\end{theorem}. The second argument to the \newtheorem command, Theorem is used to label the statement.

Step Two:

In the body of the document, invoke the proclamation by typing
\begin{theorem}
The first theorem of this article states ...
\end{theorem}

The result will look something like this:
Theorem 1 The first theorem of this article states ...

Of course, you can do the same for Propositions, Lemmas, Corollaries, Definitions, and so on.
For example, \newtheorem{lemma}{Lemma}
could be used to create a "lemma" environment. The point is that you get a uniform style to all of your proclamations, you can create cross-references to them, and they are numbered automatically.

Homework

1. Compose a document with at least 12 proclamations of at least 3 different types. Email me the source file and bring the typeset version to class. The content of each proclamation can be whatever you like -- it doesn't have to be a genuine mathematical statement. I just want you to learn how proclamations work. You could use proclamations to construct a set of instructions for a task, for making up a grocery list, etc.
2. By now you should have sent me a list of your hobbies and interests by email. Find one interesting article from a newsgroup or from a web-site and forward the article to me (not just the URL or newsgroup reference). Print out a copy and hand it in during the next class