Matt’s latest set of puzzles, as part of the Make Britain Count campaign, are online at The Telegraph. This round of puzzles is all about factors, and there have been previous puzzle sets about consecutive numbers and prime numbers.
You're reading: Main
“Futurama theorem” slightly improved
The “Futurama theorem”, also known as Keeler’s Theorem after its creator, was a bit of maths invented for the Futurama episode The Prisoner of Benda, to solve a problem where the characters get their heads mixed up and need to swap them back without any one pair swapping heads twice. It was enthusiastically reported by the geeky press, and rightly so, because it’s a fun bit of real maths with a wonderful application. Dana Ernst has written some very good slides about the theorem, working from “what is a permutation?” up to the algorithm itself.
Anyway, some students from the University of California, San Diego have extended the result, giving a better algorithm for finding the minimum number of switches to put everyone’s head back in the right places, give optimal solutions for two particular situations, and give necessary and sufficient conditions for it being possible to represent the identity permutation as $m$ distinct transpositions in $S_n$.
Paper: http://arxiv.org/abs/1204.6086
via James Grime
Report criticises level of mathematics in A-level science
An article on the BBC website says that a report by SCORE has found that A-level science exams do not contain enough maths questions to prepare students to progress to science degrees or related jobs.
Grow Your Own Food
I recently heard about Herman, the German Friendship Cake (bear with me), a cake which is divided and spread among friends, and it got me thinking about some other foodstuffs I’ve heard of which are made in such a way that the amount you have will grow exponentially. A Herman cake is a special type of sourdough cake which is made with yeast. It’s explained fully here, but the idea is that you start with a solution of yeast, which lives in a little milk, sugar and flour. This small amount of goo can live happily at room temperature on a shelf, and if you stir it every day and give it a little more flour and sugar to eat every few days, after ten days it’s ready to make into a cake.
IMA YouTube page launched
The Institute of Mathematics and its Applications have launched a YouTube channel.
World record mass Rubik’s Cube solving attempt in aid of youth homelessness charity
In June 2011 Depaul UK, a youth homelessness charity, broke a world record by having over 300 people in one place solving the Rubik’s cube at the same time. You can view photos of the event on their Flickr page and watch a video covering the attempt below.
Today only: The Geek Atlas ebook half price
I don’t really intend this to be an advert but for a while now I’ve half intended to pick up a copy of John Graham-Cumming’s The Geek Atlas. I just bought a DRM-free ebook half price as part of an International Day Against DRM promotion.