## Countability of the rationals drawn using TikZ

I’m continuing my exploration of TikZ (here is my first post about TikZ). I will be showing my Discrete Math class how to “count” the positive rational numbers. (See this old blog post for more information about countable sets.) I used TikZ to create the picture below. Here is the source code for this figure. If you click…

## Bubble diagrams for functions in LaTeX using TikZ

I am teaching Discrete Math this semester (our intro-to-proof course). One of the topics is functions. Not surprisingly my students and I have to draw “bubble diagrams” for functions between finite sets—and we have to include them in LaTeX documents. Rather than simply sketching them in Adobe Illustrator and importing them as graphics, I decided…

## The Pigpen Cipher in Latex

Recently my son and his friends have been enjoying sending secret messages back-and-forth using the pigpen cipher (also called the masonic cipher or Freemason’s cipher). It produces codes that look like: The pigpen cipher is a simple substitution cipher—there is a 1-1 correspondence between these special symbols and letters of the alphabet. The correspondence is…

## Online LaTeX editors

For the last 10+ years I’ve taught topology using a modified Moore method, also known as inquiry-based learning (IBL). The students are given the skeleton of a textbook; then they must prove all the theorems and solve all of the problems. They are forbidden from looking at outside sources. The class types up their work as…

## Ancient number systems in XeTeX

I am teaching a history of mathematics class this semester. We are beginning with a brief discussion of ancient number systems: Egyptian, Babylonian, Mayan, Chinese, Incan, Greek, Roman, and Hindu-Arabic. As I was writing up the first homework assignment it occured to me that I should investigate whether these numbers could be typeset using LaTeX. It…

## A quick guide to LaTeX

This semester I’ll be teaching real analysis. I am going to have the students type their homework in LaTeX. To make this as easy for them as possible, I will give them a template that is all ready for them to enter their solutions. They shouldn’t have to worry about headers, packages, font sizes, margins,…

## Some LaTeX odds and ends

Here are a few LaTeX tricks I’d like to share. None of them are earth-shattering, but maybe they’d be useful to some of you. (If you want to try these out, you can download this sample tex file and bib file that contains these tricks.) 1. I have always wanted LaTeX to support inline comments. In many…

## Tricks for easily creating BibTeX files

I wrote my last book (my only book, that is) using LaTeX. I had a large bibliography with close to 400 entries. I stored all of the bibliographic items in a BibTeX file (a text file ending in .bib). Each item looks something like this: @book {Richeson:2008, AUTHOR = {Richeson, David S.}, TITLE = {Euler’s gem:…

## Coffee stains and the Simpsons in your LaTeX document

A few weeks ago John D. Cook posted a tweet asking for suggestions for his @TeXtip Twitter feed. Usually @TeXtip posts are useful tips or factual tidbits about the typesetting program. I decided to send him a humorous suggestion instead. He posted the tip on Twitter yesterday. I sent him a link to Hanno Rein’s coffee.sty package…

## Posting items to my blog using wplatex

This blog post is aimed at other mathematicians who write on WordPress blogs. I’m writing this blog post completely in TexShop on my Mac! Recently I discovered that Eric Finster at Curious Reasoning wrote a Python script called wplatex that converts LaTeX documents to HTML that is WordPress compatible. Then it posts the files directly…

## A new way to collaborate: DropBox

I have a long-time collaborator who lives in Georgia (I’m in Pennsylvania). I’ve had good luck collaborating with him via email, but it is a pain. As soon as one of us edits a file he sends it to the other person as an email attachment. We haven’t had any “forked” files, but we do…

## LaTeX now available in Google Docs

Google Vice President and Chief Internet Evangelist (yes, that is really his title) and inventor of the internet Vint Cerf visited our campus a couple of years ago. At one point he asked about what people wanted from Google. I said that I would love a Google Docs/LaTeX mashup. How great would it be for…