# TeX, The Mathematical Typesetting Language

This page provides information about the TeX system for mathematical typesetting. It is written for the students taking Math 360 at Northern Illinois University, who have to prepare short papers with mathematical content, but may be useful for other mathematics majors and graduate students, and indeed anyone who expects to have to prepare a large number of articles, books, exams, web pages, or presentations which have significant quantities of mathematics in them -- symbols, equations, and other displays.

## Installing TeX

In order to use TeX, you need a computer. Almost any computer produced after about 1980 (!) will do. You will also need a TeX program that runs on your computer, and you will probably want some documentation. These you can get on the Internet at, for example, the Comprehensive TeX Archive Network (CTAN) or the TeX Users Group.

NIU students who have a Windows(tm)-based PC can borrow a disk from the Math department. It contains MikTek, which is a particularly complete installation of TeX. The disk also contains another program, the TeXNiC Center; you will want this one if you prefer to work in an environment which offers pull-down menus and so on. Here are installation instructions for those two programs.

There are also excellent TeX tools for Mac users, and TeX is supplied along with most every distribution of unix/linux. Ask for help if you need it.

## Understanding TeX

Here's a short description of the TeX word-processing program and why we recommend you use it. Included here is an overview of the steps you need to take to produce documents with TeX.

There's no substitute for experience! To prepare for becoming a TeX user, we offer you some sample documents; all you need to do is to become familiar with how to process them on your computer. In this first stage, we'll spare you having to actually type your thoughts onto paper by "borrowing" some previously-typed files. Use one or both of these samples:

• model0.tex -- a sample Plain TeX file. (It's the first handout about the train model.)
• paper.tex -- a sample LaTeX file.
Here are the documents which should result when you feed those input files into TeX: model0.pdf, paper.pdf

(If you'd like to see more samples in action, read here about the source for the second sample above; that will show you where to find more complex samples, or find the same sample in other formats. Warning: these samples are not for the faint of heart!)

Now practice simply taking a .tex file and feeding it through your TeX program. MikTeX calls this "building" the document, and you can use MikTeX to do it. Or you can just use the executable (tex.exe / latex.exe / pdftex.exe / pdflatex.exe / ...) directly. Here are some directions to help you with that. (The steps are just a bit different depending on whether you're using Plain TeX or LaTeX, on whether you want PDF or some other output, etc.)

## Making your own TeX documents

If you succeeded in running through the steps in the previous section, then you're ready to make your own documents in the same way. All you need to do is to create your replacement of the .tex files.

Above you found samples which were complicated; take those and try to simplify them to find something that works. Alternatively, you could begin with simpler Plain-TeX or LaTeX files. Make sure they can be processed just as easily as you did with model0.tex and paper.tex . You can make them simpler yet, if you like: delete everything from the line

   %This is a comment, because it follows a percent symbol on a line.

to the line that begins
   \end

and you will have an empty document, ready for your own pearls of great writing. Experiment a little to see if you can come up with something interesting using only those tools. For example, can you print a table showing the names of all the letters in the Greek alphabet? (You'll want that as part of your mathematical life!)

Things start to get a little trickier when you want to typeset some really arcane bits of mathematics, or when you care greatly about micro-spacing issues, or when your document gets to be so long that you need to have chapters and sections and subsections, or when you find yourself doing computer programming in TeX! (e.g writing macros and computing shapes of irregular margins). This is a level of finesse that a typical student in my class will probably not need, and at this level it starts to make a big difference whether you're using Plain TeX or LaTeX. I will just summarize the options of those students who want to learn how to use TeX more fully in other contexts:

• There are guides everywhere which try to help out the newcomers. We have some here at NIU, aimed at new grad students and faculty who will have to use this as a way of life. We usually start them off with a LaTeX template for journal articles.
• There are lengthier sets of documentation and more samples available at TeX websites. For example, the TeX Users Group beginner's page includes two useful sample LaTeX files: a tiny sample and a somewhat more complicated sample.
• There are some excellent books and reference manuals which describe exactly how the TeX systems will work. Knuth's "The TeXbook" is a premier example of how to write an extremely thorough yet readable documentation of a complex computer system.

The nice thing about computer software --- particularly open-source software like TeX --- is that you can't go wrong by just trying it out. You never really have to wonder, "Do I have to do it like this?" -- just try doing something a different way and watch to see what does or doesn't happen! The TeXbook even has a long appendix that explains how most of the complicated TeX procedures are defined (in terms of a smaller set of basic operations). So explore and enjoy!

If you need help with TeX, let me know. I have used it for over 20 years, and would be happy to help you. My preference has always been for Plain TeX input and DVI output on various Unix operating systems, but I will do my best to help you with other arrangements too.

Prof. David Rusin