Yesterday I stated four hat problems. Today’s post contains the solutions to those problems. 1. Alice and Bob are wearing hats. The hats are either red or blue. They can see each other’s hats, but not their own hat. They are tasked with guessing their own hat color. If either person gets the color right, then they…
Category: Math
Infinite hat problems
I got back from MathFest yesterday after a long 3-leg red-eye trip across the country. It was a great meeting. It is always fun to hear some good talks, visit a new city, and see old friends (and meet another math blogger). The first talk that I attended was given by Alan Taylor: “Predicting Values of…
I need to learn how to say no
I’m heading to MathFest in a few days. I’m giving a talk on some generalizations of the Japanese Theorem (which I hope to blog about at some point), I am a panelist on the AWM panel called Family Matters, and, since I’m on the MAA Committee for Minicourses, I will be monitoring two minicourses. I also hope…
New journal publishes inaugural issue
The inaugural issue of Rejecta Mathematica is now available online. In case you haven’t heard of this one-of-a-kind journal, here is part of their mission statement: Rejecta Mathematica is an open access, online journal that publishes only papers that have been rejected from peer-reviewed journals (or conferences with comparable review standards) in the mathematical sciences….
What is the LaTeX code for that?
It is hard to count how many times I’ve scrolled through Scott Pakin’s The Comprehensive LATEX Symbol List (pdf) looking for the LaTeX code for some obscure mathematical symbol. That pdf document may no longer be the first place I turn. Daniel Kirsch, a math student from Münster, Germany has created a very useful website…
Videos of past meetings of the ICM
As you may know, the 2010 International Congress of Mathematicians will be held in Hyderabad, India. This weekend I received an invitation to speak at one of the satellite conferences (Various Aspects of Dynamical Systems) at The Maharaja Sayajirao University of Baroda in Vadodara, India, which is being held immediately after the ICM. Needless to…
Quantifier soup
Anyone who has tried to teach Calculus I students the definition of the limit knows that students have a difficult time working out definitions with multiple quantifiers. In fact it is something that we must come back to again and again with our mathematics majors. While doing a little research this week I came across…
Ambigram: pie≠3.14
I thought the first comment on this article was funny. It says that pie and 3.14 are mirror images, if written in a certain way. Regular readers may recall that I had fun creating ambigrams a few months ago. This blog comment inspired me to whip up a quick ambigram exhibiting this symmetry. I like…
Last Sunday was a perfect day
Most geeky math types (like me) already know about pi day (March 14… 3/14, get it?). Writing in The Times Online, Marcus du Sautoy suggests a new math holiday: June 28. He suggests calling this day the World Math Day (actually, he suggests World Maths Day). Why? What is so mathematical about June 28? June 28 can…
Indeterminate form in The New Yorker
In Calculus II we teach our students about a variety of indeterminate forms: , , , etc. I was reminded of another indeterminate form when reading Malcolm Gladwell’s thought-provoking (negative) review of the book Free: The Future of a Radical Price, by Chris Anderson (editor of Wired). The review appears in The New Yorker (that you can read…
David Richeson: Division by Zero 