# LaTeX

### How do you typeset all those logical symbols so nicely?

Here is a template that will get you started with logic in LaTeX: logic-template.tex.

Download that and the file fitch.sty. Make sure you’ve installed LaTeX. Then pdflatex logic-template to produce a PDF, logic-template.pdf.

### How can I learn how to use LaTeX?

There are many online books and tutorials. Among the best:

### Where do I get LaTeX? Is it expensive?

It’s free. If you use Windows, you’ll want to get MikTeX (which contains the LaTeX system itself) and either WinShell or TeXnicCenter. If you use a Mac, you’ll want MacTeX. If you use linux, get TeXLive (on debian-based systems, apt-get install texlive).

### How do I typeset logic using LaTeX?

I use this package for Fitch-style proofs and this one for numbered examples. Here’s a template to get you started, and here’s the PDF it produces after processing with pdflatex.

Here’s the style file I use for the handouts: handout.sty. Put this in your working directory. Then your latex file can look like this:

\documentclass[11pt]{article}
\usepackage{handout}

\date{\today}

\begin{document}

\maketitle

Here's my proof:

$$\begin{fitch} \fh \neg\exists x(Gx \wedge Hx) & \\ \fa \forall x \neg(Gx \wedge Hx) & QE 1 \\ \fa \fh \framebox{b} & \\ \fa \fa \neg(Gb \wedge Hb) & \forall Elim, 2, b/x \\ \fa \fa \fh Gb & hyp \\ \fa \fa \fa \fh Hb & hyp \\ \fa \fa \fa \fa Gb \wedge Hb & \wedge Intro, 5, 6 \\ \fa \fa \fa \fa \bot & \bot Intro, 4, 7 \\ \fa \fa \fa \neg Hb & \neg Intro, 6--8 \\ \fa \fa Gb \supset \neg Hb & \supset Intro, 5--9 \\ \fa \forall x(Gx \supset \neg Hx) & \forall Intro, 3--10, b/x \\ \end{fitch}$$

\end{document}

You can use detexify to find the codes for symbols you want to use. If you don’t find what you want there, try the big list.

### How do I get an upside-down iota (Russell’s definite description operator)?

In the preamble of your document,

\usepackage{graphicx}
\newcommand{\riota}{\rotatebox[origin=c]{180}{$\iota$}}

Then just use $\riota$. (Thanks to Alexander McCormach.)

Alternatively, you can get the phonetic.sty package and put

\usepackage{phonetic}

in the preamble. (Thanks to Raul Saucedo.)