Introduction to LaTeX: 3. Miscellany

Tables

While generating tables in Plain TeX (and AmSTeX) is difficult and can be a very frustrating experience, this is not the case with LaTeX. LaTeX has simple, intuitive, and user-friendly macros for tables, and typesetting good looking tables in LaTeX is a breeze, and can be fun.

The idea is to think of the table as a matrix, consisting of rows and columns. The data is entered one row at a time, with double backslashes (\\) separating the rows, and ampersands (&) separating the entries within each row. A surrounding pair \begin{tabular}{...} ... \end{tabular} then does all the work. Here the argument of the first brace {...} consists of a "template" that specifies the positioning of the table entries: l, r, or c, for left, right, or center. Here is a very simple example:


\begin{tabular}{l r r r c} 

Name&Exam1&Exam2&Exam3&Grade\\
John&19& 28&33&C \\
Jane&49& 35&60&B  \\
Jim&76& 38&59&A 

\end{tabular}

Note that TeX automatically chooses the width of the columns and the heights of the rows so that all table entries fit, with some room to spare.

Now let's spruce up this table, by surrounding it with a frame, and separating columns and rows by "rules" (vertical and horizontal lines). This is easy to do: To get horizontal lines add "\hline" at each linebreak and at the beginning and end of the table. To get vertical lines (and also specify the positioning of the data entries - left, center, or right), add vertical bar characters ("|") to the template, e.g.: { | l | r | r | r | r } If you use a double bar symbol "||" instead of a single bar, or use a double "\hline", the separating lines get "doubled". This provides an easy way to separate the headers from the table contents.

Here is the above table with these enhancements.


\begin{tabular}{| l || r | r | r | c |}  

\hline

Name&Exam1&Exam2&Exam3&Grade\\

\hline\hline

John&19& 28&33&C \\  
\hline
Jane&49& 35&60&B  \\
\hline
Jim&76& 38&59&A  \\

\hline

\end{tabular}

Exercise 3.1: Build a table like the one above (or paste the above code into a LaTeX article template), compile the TeX file, and look at the typeset table.

There are two additional enhancements you might want to make with the above table. The first is to center it, by surrounding the entire construct with a \begin{center} ... \end{center} pair.

The second enhancement is to surround everything by a \begin{table} ... \end{table} pair. This makes the table a "floating" table, meaning that TeX chooses an appropriate placement, so as to avoid bad page breaks. For example, if at the current location the table would run over the bottom of the page, TeX will fill the page with text, and place the table at the top of the following page. The "table" environment also enables one to add a "caption". The result is something like the following:


\begin{table}
\begin{center}
\begin{tabular}{ .....}

......

\end{tabular}
\caption{Math 361 Grades} 
\end{center}
\end{table}

Exercise 3.2: Enhance your table in this manner, by centering it and adding a caption. Note that LaTeX automatically gives the table a label of the form "Table 1: ....". If you had a second table, it would be called "Table 2: ...". Try to typeset several (possibly identical) tables, with a few paragraphs of text in between, and see how TeX chooses the placement of the tables. (Note: The positioning doesn't always come out where you'd expect or want it. See the Gratzer book for ways to get around such problems.)

Mathematical material in tables: If the table entries involve mathematical notation, they should be placed inside single dollar signs: For example, x² has be entered as $x^2$.

Lists

LaTeX has two basic list environments: The "itemize" environment which produces a "bullet list", and the "enumerate" environment which generates a numbered list. These enviroments are similar to the <ul> and <ol> environments in html: The list items are introduced with the command "\item", which is analogous to the html code <li> . Here is an example of the first type of list:


\smallskip

\textbf{Some special characters in TeX:}

\begin{itemize}

\item Accents  

\item Braces 

\item Dollar signs 

\end{itemize}

Replacing "itemize" by "enumerate" will create a numbered list (without any further changes - the numbers are generated automatically!).

Lists can be nested. In numbered lists (i.e., those generated by "enumerate"), the numbering style changes from one level to the next. The items at the top level are numbered 1., 2., etc., those at the next level are numbered alphabetically by (a), (b), etc. Note that the numbers are generated automatically - you don't have to enter them!

Exercise 3.3: Typeset the following set of exercises using correct TeX constructs:
1. Differentiate the following functions:
(a) f(x) = x²
(b) f(x) = log x
2. Integrate the following functions:
(a) f(x) = square root of x
(b) f(x) = sin x cos x

Fonts and spacing commands

The most important rule about font changing and spacing commands is to avoid using them! You should normally leave font and spacing matters up to TeX. If you don't like the way a document looks, try another documentclass (e.g., article instead of amsart), add an option to the documentclass, or add a global instruction to the preamble of the document, before \begin{document}. Options are specified in square brackets before the name of the class (which is enclosed in braces). Here are few such changes you might want to make:

Changing page dimensions: To change the width and height of the printed text, add instructions such as the following to the preamble (i.e., after \documentclass and \usepackage, but before \begin{document}:
\setlength{\textwidth}{5in} \setlength{\textheight}{7in}.
Here "in" stands for inches, and is one of several units that TeX knows about. Other units include cm (centimeters), mm (millimeters), and pt (points - see below).
Changing the font size: The default font size for ordinary text is 10pt; this means 10 "points", where a point equals 1/72 of an inch. To get a larger font size, e.g., 12pt, in the "amsart" documentclass, use \documentclass[12pt]{amsart}. The same works for most document classes, and with 11pt instead of 12pt. (You could specify 10pt, but that's the default anyway so it will have no effect.)
Note: The Plain TeX "\magnification" command does not work under LaTeX. To magnify a document, change the font size and the page dimensions as indicated above.
Equation numbers on left (or right): In the amsart document class, equation numbers appear by default on the left, whereas in the article and book classes, they appear on the right. To change the positioning of equation numbers, add an option "leqno" or "reqno" to the documentclass, e.g.: \documentclass[reqno,11pt]{amsart}. (This example also illustrates how to specify several options, by separating them with commas.)
Paragraph indentations: By default (in most document classes), all paragraphs except for the first paragraph in a section are indented. To disable the indentation, set the "parindent" parameter to zero, by adding this to the preamble:
\setlength{\parindent}{0in}
To add additional spacing between paragraphs, set the "parskip" parameter to an appropriate value. For example:
\setlength{\parskip}{10pt}

Explicit font and spacing instructions: As mentioned, it is generally a bad idea to "hand-code" font and spacing instructions. (In fact, I have a program that counts such hand-coded items in a TeX file and assigns a "badness" score depending on how many there are, with zero being a perfect score.) That said, there are situations where manually coded items are appropriate, so here is a quick rundown on the most important of these:

Font changes: \textbf{....} puts the material enclosed in braces in boldface; \textit{...} puts it in italic font. Note that, as the name indicates, these commands are for text mode only. To change the font in math mode (something that is rarely necessary), use the analogous commands \mathbf{...}, \mathit{...}.
Changing font size: To change the size of a font manually, use a command such as \large (one step up from normal), \Larger (two steps up from normal size), \normalsize (normal size), or \small (one step down from normal size). These commands stay in effect until the next size changing command. The \normalsize command returns the font size back to normal. Again, this works for text mode only. For math mode there are similar commands; of these, there is only one, "\displaystyle", that you might want to use on occasion. "\displaystyle" has the effect of enlarging a font that would otherwise be too small to be legible. The latter might occur in stacked subscripts, superscripts, fractions, or limits to sums or integrals. For example, in the expression $\frac{e^{x^2+1}}{x}$ (set "inline") the exponent $2$ is likely to be too small to be legible. To remedy this, and increase the size of the expression by one notch, precede "\frac" by "\displaystyle" (within the $ ... $ pair).

Exercise 3.4 Type a few sentences containing the above expression, (a) "inline" without \displaystyle, (b) inline, but with "\displaystyle", (c) as a displayed formula, enclosed by a bracket pair (without \displaystyle), and (d) inline, but with the fraction written in slash notation (i.e., $e^{x^2+1}/x$). (The latter is probably the best of the three inline versions; even better would be to use "exp" in place of "e" ( $(1/x)\exp\left{x^2+1 \right}$), since then only one level of super/sub-scripting is involved.) Observe how TeX sizes the various components in this expression, depending on whether the formula is inline, or displayed, and whether or not it contains the \displaystyle instruction.
Indentations: Paragraphs are normally indented, except for the first paragraph in a section. To prevent this indentation, use \noindent right before the paragraph. The opposite command, \indent, causes TeX to indent material that would normally not be indented, These commands should be used very sparingly; if you want to disable indentation completely, set the "parindent" parameter to zero inches, as shown above. A common mistake is to leave blank lines before or after displays. Blank lines are interpreted by TeX as paragraph breaks, so the text following such a blank line is being indented. I have seen many papers where authors make the mistake of surrounding every display by blank lines, then realize that this causes unwanted indentations, and try to undo the damage by adding \noindent's every time. Here is an extreme example of this, a small excerpt from a paper whose author shall remain anonymous. The example is instructive, because it shows many other bad habits. As a result, the author probably spent twice as much time typing the document than he would have needed otherwise, and the technical editor (which, in this case, was me) had to waste hours to undo the damage.
Line and page breaks: To force a line break at a particular spot, say \newline; similarly, to force a page break, use \newpage.
Vertical spacing: You can specify an arbitrary amount of vertical space by the \vspace{...} command, e.g., \vspace{1.5in} generates 1.5 inches of space. However, it is usually better to just use one of the following three standard commands for creating a small amount of vertical space:
\smallskip, \medskip, \bigskip.
\smallskip is appropriate, for instance, before and after a "manually" coded theorem. (If you use the \begin{theorem}... \end{theorem} construct (see below), the spacing will be generated automatically.)
Horizontal spacing: To explicitly specify a horizontal space in text mode, you can use \hspace{...}, with ... being the amount of space needed. Creating horizontal space in this manner is very rarely appropriate and not recommended. In math mode, however, there are situations where you want to add a small amount of horizontal space, e.g., to separate two equations on a single line. In most of these cases, specifying "\quad" gives you the right amount of space. Other spacing commands in math mode include "\," (a tiny amount of space), "\!" (a tiny amount of "negative" space), "\qquad" (twice the amount of space generated by a \quad).

Error messages

As you begin doing more complex things, it is more likely that you will encounter error messages while compiling the file. Often, these error messages are cryptic, and it may be hard to figure out what is wrong. Here are some typical situations:

Undefined control sequence: This (usually) means what it says: TeX encountered a command that it didn't know about. The offending command is shown in the error message (look for items beginning with a backslash). Often, this is due to a simple typo. Sometimes, it's a command that is defined in one of the AMS extension packages, some of which have to be explicitly loaded. This problem can be prevented by adding the line
\usepackage{amsmath, amsthm, amssymb,amsfonts}
after \documentclass{...}, to load the main ams packages. Depending on the documentclass, some of these packages may get loaded automatically, but it doesn't hurt to load them anyway. The impact on performance is minimal.
Overfull/underfull vboxes/hboxes: These are warning messages that indicate that TeX wasn't able to fill lines or pages to its rather strict specifications. If you look at the output, you may see lines sticking out to the right. For drafts, simply ignore these messages, especially if the excess is small. If a line is significantly overlong, which occurs mainly in displayed equations, break the display into several lines using the "align" or "align*" environment.
Missing $ inserted: This is usually an indication that TeX found material that needs to be set in math mode. For example, the expression "x^2" should be enclosed in dollar signs. It could also be a sign that a math mode instruction didn't have a corresponding "end math mode" instruction.
Extra }, or forgotten $: An indication that there is a mismatch of opening and closing braces, or opening and closing math mode instructions. Often the result of a forgotten brace in complex fractions (an example being \frac{e^{x^2+2}+2}{\log(x^2+2)+e^{x^{2n}} - can you spot the missing brace?). Those types of errors are hard to diagnose.

The best strategy in most cases is to note the line number displayed in the error message, exit the compile phase by typing "x", and look at the document at or near this line number, in the hopes of spotting the error. If you don't succeed, ask someone. Some errors can be extremely frustrating and hard to locate.

Odds and ends

Here is a partial list of topics that we haven't covered here. Learn these as needed, using Gratzer's book as a reference.

Theorems and such: TeX has special environments for Theorem-like constructs ("Theorem", "Lemma", "Conjecture", etc.) that, aside from displaying the theorem in an appropriate font, and adding some space before and after the theorem, do things like automatically number the theorems. See Sections 3.4 and 3.5 of Gratzer. You can set theorems manually, e.g., as follows.
```
\smallskip

\noindent\textbf{Fermat's Last Theorem.}
\textit{For $n\ge3$, 
the equation $x^n+y^n=z^n$ has no non-trivial integer solutions.}

\smallskip

\begin{proof} See Wiles [3].
\end{proof}
```
However, if you have more than a few such constructs, it's worth using the built-in theorem environments which do a much better job in formatting theorems.
Labels and references: Equations, theorems, sections, etc., can be given labels, to which one can refer back later on. LaTeX then translates the labels into equation numbers. For example, if the above theorem had been typeset with the theorem environment, it could have been given the label \label{fermat}, in which case you could refer to it by saying "By Theorem \ref{fermat}, the equation $x^3+y^3=z^3$ has no non-trivial integer solutions." If this were the third theorem, LaTeX would translate "Theorem \ref{fermat}" into "Theorem 3." The same mechanism works for numbered equations. This is handy since you don't have to change the theorem/equation numbers. if you insert an additional theorem or equation.
Bibliography: The simplest way to add a bibliography in LaTeX is to use the "thebibliography" environment, which sets the references using a modified version of "\item", namely "\bibitem", and allows you to refer to bibliographic references with a \cite{...} instruction, such as \cite{wiles}, where "wiles" is the "key" for the appropriate bibliography entry. See Section 6.5 in Gratzer's book. A more complex, but much powerful bibliography system is "bibtex", explained in Chapter 10 of Gratzer. However, bibtex has a steep learning curve, and it is probably overkill for small to medium-size bibliographies. I would only recommend looking into bibtex if you have a large bibliography, with a hundred or more of references.
More math: LaTeX has many more commands and constructs for typing mathematical material. These are found in Chapter 4 of Gratzer. Rather than working through this chapter systematically, I would recommend referring to it only as needed, e.g., if you encounter an expression that you don't know how to typeset.
Macros: You can define your own commands ("macros") using "\newcommand". For example, if you have a manuscript with dozens of epsilon's, you can save yourself some typing by defining "\eps" to be a macro for "\epsilon" as follows: \newcommand{\eps}{\epsilon}. Note: Avoid using the Plain TeX command \def; it does work in LaTeX, but \newcommand is safer and has greater functionality.

How not to typeset LaTeX

Here are some examples of awfully bad TeX typing; they are more common than you think. All cases involve extensive use of hand-coded formatting. The TeX files compile okay, but the output doesn't look good, and fixing up these papers (so as to meet publisher's specifications) is an arduous and time-consuming task.

Bad example 1. Source file (text); Compiled version (pdf);
Bad example 2. Source file (text); Compiled version (pdf);
Bad example 3. Source file (text); Compiled version (pdf);

Exercise 3.5: Take a look at one of the above source files, and try to spots errors and bad habits. What would you do to fix up the file?

Resources

Online resources

TeX Resources. A local list of selected online resources.
Introduction to LaTeX. The website for this course.
Math into LaTeX, Chapter 1. A free online version of Chapter 1 of Gratzer's book "Math into LaTeX" (see below).
LaTeX Tips: Basic tips. A home grown list of basic LaTeX tips, geared towards mathematical typesetting. Even if you believe you know LaTeX well, you should look at this list; you'll likely learn a few new things and tricks that make working with LaTeX easier. For additional, more specialized collections of tips see the TeX Resources page.
UK TeX FAQ. The "official" TeX FAQ, maintained by the UK TeX Users Group. Very comprehensive.
CTAN (Comprehensive TeX Archive Network). The official repository of TeX-related software.

Books

One could certainly learn TeX/LaTeX entirely from online materials, but anyone serious about learning TeX should buy a book. It is a worthwhile investment that will likely be useful for a long time. Unlike books about commercial software which become obsolete as soon as a new version comes out (who would want to buy a book on Windows 95 today?), TeX is a stable system, and books on TeX have a long half-life. There are dozens of books on TeX, but there is only one you really need: Gratzer's "Math into LaTeX". Most of the books on the market are either inappropriate for beginners, or do not adequately cover mathematical typesetting.

A must-have: George Gratzer, "Math into LaTeX". This is the standard reference on LaTeX with the AMS flavor, and a must (IMHO) for anyone planning to write mathematical papers in LaTeX. None of the other beginner-level books on the market covers the AMS packages that are essential for any serious mathematical typesetting (amsmath, amsthm, amsfonts, etc.) in any detail. Even if you have already another introductory book, it's worth buying this one. The first chapter serves as a good stand-alone introduction to LaTeX; this chapter is also available online at http://www.ctan.org/tex-archive/info/mil/mil.pdf.
A bare bones choice: George Gratzer, "First steps in LaTeX". A slimmer version of the above book - about 100 pages versus 450 pages for the full version, Good as an introductory text or for a crash course, but you will likely need to buy a more comprehensive text or reference, once you have outgrown this book. If you have the other book (Math into LaTeX), you won't need this one.

For most people, the Gratzer book is all they need. For those past the beginner level who really want to delve deeper into LaTeX, here are two additional recommendations, both at the intermediate-advanced level:

H. Kopka, P. Daly, "A guide to LaTeX": Probably the best and most comprehensive reference on LaTeX proper (as opposed to add-on packages which are discussed in the next item).
M. Goossens, F. Mittelbach, A. Samarin, "The LaTeX Companion"; Goossens, S. Rahtz, F. Mittelbach, "The LaTeX Graphics Companion": These two books cover many of the "packages" and add-ons available for LaTeX and are of interest for those wanting to use some of these packages.

How to get the TeX software/program

If you do all your TeX work on the Math Department's Unix system (which is what I do - using ssh if I am at my home computer - and what I would strongly recommend), you don't have to worry about this. The TeX system we have is reasonably current, actively maintained, and probably more comprehensive than any system you might install on your own. If you use the departmental TeX installation, you can get help in case of problems through the help and texhelp email addresses, but if you work on your home computer, you are on your own. Another advantage to doing all your work on your Unix account is that your files will all be in one place, and you don't have to transfer files back and forth from your home machine to your Unix account.

If you really still want to have a local copy of the TeX software, here are the recommended options, depending on the OS you are using.

Linux: In that case there is nothing to install, since all major Linux distributions include a full TeX installation. The Linux versions are very similar to that on our departmental Unix network, so it should be easy to find your way around, and to switch from working on a local Linux machine to working on the departmental network.
Windows: MikTeX, is a free and well supported TeX distribution for Windows, arguably better than any commercially available system (for which you'd have to shell out a few hundred dollars).
MacOS: OzTeX is a good shareware system.

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Last modified: Fri 24 Aug 2007 12:33:42 PM CDT ajh@uiuc.edu