I loved Sherlock Holmes mysteries when I was a child. A few years ago I learned the disappointing news that Sir Arthur Conan Doyle was a spiritualist who believed in séances. Because of this, his once close friend Harry Houdini became a rival. Their falling out began when Houdini joined the Doyles for an intimate séance,…

# Month: September 2008

## Technology of today’s students

Amherst College has over 1680 students. Of them, only 14 have desktop computers and 5 have landline telephones. Here is an interesting list of IT related facts about the college and their students. [via]

## Königsberg today

In 1736 Leonhard Euler solved the now-famous bridges of Königsberg problem. It is often hailed as the birth of topology and graph theory. Although no graph appears in Euler’s paper, his argument is topological in spirit. (He proved another famous topological theorem a decade and a half later.) The problem is stated as follows. If a resident of Königsberg…

## What is the difference between a theorem, a lemma, and a corollary?

I prepared the following handout for my Discrete Mathematics class (here’s a pdf version). Definition — a precise and unambiguous description of the meaning of a mathematical term. It characterizes the meaning of a word by giving all the properties and only those properties that must be true. Theorem — a mathematical statement that is proved using rigorous mathematical reasoning. In…

## Aggregating political polls

A colleague and I were talking about how fun it would be to be teaching a statistics class during this presidential election season—especially talking about the political polling process. Recently I came across Fivethirtyeight.com, an interesting website that takes published political polls, applies its own analysis to them, and puts out its own predictions. (It is named after the number of electors in…

## They Might be Giants sing about polygons

Here is a fun video from They Might be Giants. It is from their children’s CD/DVD Here Come The 123s, the follow up to Here Come the ABCs. The song is called “Nonagon”. (I feel bad for Heptagon, who apparently wasn’t invited to the party.)

## Learn the Greek alphabet

I’m a big fan of Sporcle, a website that has, as they describe it, “mentally stimulating diversions.” When I was in graduate school, one of my fellow graduate students had a terrible time learning the Greek letters. He forgot the easy ones—he repeatedly called lambda, gamma and phi, psi. His advisor joked (I think he…

## Banach Obama

I have no intention of posting political items to the blog, but I got this email from a friend of mine and it made me laugh. So I thought I’d pass it along. While shopping the other day I saw this dude sportin’ a “Banach Obama” tee shirt, so naturally I had to talk to him….

## Joke of the day

Two mathematicians walk into a bar. One is complaining about the state of mathematics education in America. “The average person just doesn’t know any math,” she exclaimed with disgust. The second mathematician said that he didn’t think things were so bad. After they placed their drink order with the server, the man excused himself to…

## Prime number worth $100K

The Electronic Frontiers Foundation was offering a $100,000 bounty on the first Marsenne prime with over 10 million digits. A Marsenne prime is a prime number of the form . The first 10 million digit prime was discovered on August 23, 2008 by a computer at UCLA. The prime, , has 12,978,189 digits. It was discovered as part…

## Cloud computing makes me nervous

After the recent news of Freddie, Fannie, Bear Sterns, Lehman Bros, Merrill Lynch, and AIG, I got to thinking about how much of my work is online—Google Docs, Gmail, WordPress, Wikidot, etc. If our highly-regulated banking industry can fail, why not these young unregulated internet sites? Should there be an FDIC equivalent for the “banks” that…

## The nuts and bolts of writing mathematics

This was a handout that I made for my Discrete Mathematics class. At our college this course is the gateway to the mathematics major and is the students’ introduction to writing mathematical arguments. Here is a pdf of the handout. The nuts and bolts of writing mathematics You know that I write slowly. This is chiefly…