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…
Category: Math
Happy tau day!
It is 6/28! Happy tau day—a day that is twice as fun a pi day! Let’s celebrate our new favorite mathematical constant: Remember, as Bob Palais told us, is wrong! I’m a fan of tau.
12 scholarly hoaxes, randomly generated articles, and other tricky fun
Everyone loves lists. Just for fun, here’s a (very) loosely-organized list of scholarly hoaxes, randomly generated content, and other interesting tidbits. Some of these I learned about recently, some I’ve known about for a long time. Theorem of the day—This website creates randomly generated “theorems.” Rejecta Mathematica—This journal publishes only articles that have been rejected by peer-reviewed…
What’s in a name?
I had an interesting interaction on Twitter today. I’m doing some research with a student that involves a little graph theory. We needed some graph theory terminology that I was sure was well-known (but not known to us), so I turned to Twitter. Let be a vertex of directed graph. Define to be the set…
The earth is big
I just stumbled upon this neat infographic which shows relative heights of objects from the top of Mount Everest all the way down to the bottom of the Mariana Trench. The top of the graphic is at an elevation of 38,000 ft and the bottom is 38,000 ft below sea level. The infographic image is…
Catching up on some reading: Dyson’s birds and frogs
The semester’s over and I’ve been cleaning off my desk. I found an old issue of the Notices of the AMS (February 2009) with a bookmark in it. It was Freeman Dyson‘s Einstein Lecture entitled “Birds and Frogs.” Here are some good quotes from it. He opens with: Some mathematicians are birds, others are frogs….
Turing’s topological proof that every written alphabet is finite
Recently one of my colleagues was reading Alan Turing‘s groundbreaking 1936 article “On Computable Numbers with an Application to the Entscheidungsproblem.” This is the article in which Turing introduced the turing machine, solved Hilbert’s Entscheidungsproblem (`decision problem’), and proved that the halting problem is undecidable. It is viewed by many as the foundation of computer…
Mathematics in novels and Martin Gardner RIP
I always enjoy encountering mathematics in non-mathematical works of fiction. (I posted excerpts from Candide and The Brothers Karamazov last fall.) Here are a few more that I came across recently. The first is in Dashiell Hammett’s 1934 murder mystery The Thin Man. Here is a conversation between private eye Nick Charles and his wife Nora at the…
Volumes of n-dimensional balls
We all know that the area of a circle is and the volume of a sphere is , but what about the volumes (or hypervolumes) of balls of higher dimension? For a fun exercise I had my multivariable calculus class compute the volumes of various balls using multiple integrals. The surprising results inspired this post….
Movie day in topology class: the Poincaré conjecture
Today was the last day of the topology class I’ve been teaching. I decided to devote the day to the Poincaré conjecture. I started by telling the students a little about the history of the problem. Then I showed them three videos. The first video was an excellent 50-minute lecture by Fields medalist Curt McMullen…
David Richeson: Division by Zero 