Morris: Futurama – Prisoner of Benda

Futurama: The Prisoner of Benda

Smart shows have smart writers, and none are smarter than the writers of Futurama.  We’ve seen a number of clever math references in Futurama and the Simpsons.  Now a fully fledged theorem is written up on screen.

Sweet Clyde's Inversion Theorem

If I had a TV show that’s exactly what I would do.  As it is I just post on Math Factor.

The theorem is by staffer and Math PhD Ken Keeler.  In the show Harlem Globetrotter, and all-round genius, Sweet Clyde comes up with a theorem to solve an apparantly intractible problem.

To quote Professor Farsnworth ‘Who says pure maths isn’t useful in the real world!’

Professor Farnsworth invents a mind-switching machine.  A lot of plot later nine people have their minds in the wrong bodies.  Unfortunatley the machine has a limitation, it cannot process the same two bodies twice.

There seems to be no way out until Clyde and EthanTate enter.  Clyde comes up with ‘Sweet Clyde’s Inversion Theorem’ and saves the day.

He shows that however many people there are, and however mixed up their minds, it is always possible to get every mind back in the right body as long as you have two extra bodies to help, and you know your maths!

This is the mess they are in:

Fry’s mind is in Zoidberg’s body

Professor’s mind is in Bender’s body

Bucket’s mind is in Amy’s body

Leela’s mind is in Professor’s body

Emporer’s mind is in Bucket’s body

Hermies’ mind is in Leela’s body

Zoidberg’s body is in Fry’s body

Bender’s mind is in Emperor’s body

Amy’s mind is in Hermies’ body

Take a moment to solve this yourselves.  Remember you need to get each mind back in the right body by repeatedly switching the minds of two bodies.  No switch can be repeated.  You cannot switch two of the original nine bodies because we have lost track and assume those combinations have already been used.  So every switch must involve Clyde and/or Ethan.  

Read on for the solution.

Read the rest of this entry »

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Morris: Golden Earring – Radar Love

Goose-pimple time - I LOVE  this songTrauma at home; my wife has just lost one of her golden earnings.  Fortunately I know someone who will sell me a bunch of similar earrings, for a price!

I know that one of his earrings is fake, but that’s okay because I can work out which one, replace my wife’s earring and still make a profit. 

I will have to bring out my earring weighing machine, the Radar Love, which lets me compare two groups of earrings and tells me whether one group is heavier or lighter than the other, or whether they are the same wieght.  This is the only clue I will get.

The Radar Love only has three charges.  At most how many earrings can I have bought and still be confident that I will find the fake?

Can you find a general formula for a given number of charges?


Morris: The Crack that Lets the Light In

“There is a crack in everything, that’s how the light gets in” Leonard Cohen, ‘Anthem’

Berlin Wall Chink of Light


It is the things that don’t make sense that teach us the most.  

If you want to learn something new, start with something you don’t understand, something which doesn’t make sense.

However much you know there will always be chinks in your knowledge, chinks of light that may lead you to somewhere beautiful.


Consider this:

On a Sunday afternoon your prison guard tells you that he will conduct a surprise inspection at 10am over the next seven days.

You work out that he can’t wait until next Sunday, because then it wouldn’t be a surprise. 

So, could he do it on Saturday?

On which days would the inspection be a genuine surprise?

There is no consensus on this, which is why I describe it as a chink of light, a way to get at something deeper.  But what do you think?

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HA! Conway on Gardner

In this special segment, John H. Conway reminisces on his long friendship and collaboration with Martin Gardner. 

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Morris: RIP Martin Gardner: 1914 – 2010

Topsy-Turvy GardnerMartin Gardner died this week.

One of his books is on my coffee table.  This is not a coincidence, there is always one of his books on my coffee table.

Many of my puzzles have come from these books.

I know him as the greatest collator and populiser of math puzzles, but of course his talents went far beyond this.

Rather than try to do my own second-rate obituary I will just point you at some links.

Scientific American, for whom he wrote for 25 years.,%201914-2010

Make your own Martin Gardner Flexagons here,

The Daily Telegraph on his deconstruction of Lewis Carroll’s Alice books,

He wrote over 70 books.  Nothing I can say can begin to encompass his long and amazing life.  He is someone you need to discover for yourself.

He is already missed.


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GY. Chaitin on the Ubiquity of Undecidability

Greg Chaitin, author most recently of MetaMath!,  discusses the ubiquity of undecidability: incredibly all kinds of mathematical and physical systems exhibit utterly unpredictable, baffling behavior– and it’s possible to prove we can never fully understand why!

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Update: The Math Factor Podcast

The Math Factor podcast is taking a rest for a while — we’ll be back with new podcasts at some point (probably, we think) so check back every once in a while!

In the meantime, from time to time the Math Factor crew will still be posting here, on our traditional highly irregular schedule.

I’m really proud of the bookends to the pieces so far: Cantor’s Theorem, in the segments leading up through AH. QED and now the discussion of undecidability in the last two podcasts. Along the way, we’ve managed to get in quite a bit of sophisticated stuff — not bad for local radio! 

I’ve really enjoyed all the conversations the Math Factor has initiated, between me and Kyle, with mathematicians and those using mathematics to do really interesting stuff, with book authors, and especially all those who have written in — and even become active collaborators! (Hi Jeff and Stephen) The tremendously supportive feedback we’ve gotten really means a lot.

I think it’s time, though, to take an extended break from the podcast. Kyle is now incredibly busy producing five hours of original magazine format radio journalism a week. He’s always been a dynamo, but lately the man’s a blur! And much of my energy has been directed elsewhere too (check out!) I’ve started a couple of books that I hope you’ll check out when the time comes, and in the meantime, please read my articles Can’t Decide? Undecide! and another on tilings and computation.

I’ll be hanging out in Marseille, Mexico City and Oaxaca in June, with a lot of neat people, so might get all inspired to make some new posts soon, but on the whole, I feel like I’ve said what I needed to say for a while. The Theory of Computation is really an astounding and important perspective, and I’m delighted to have helped spread the word a bit more. It’s a great resting spot!


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GW. Wolfram’s Principle of Computational Equivalence

Stephen Wolfram, creator of Mathematica and author of A New Kind of Science, discusses the Principle of Computational Equivalence and why even simple systems can give rise to irreducibly complex behavior. 

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G4G9: Report From the Festivities!

Quick interviews with folks here at the Gathering For Gardner, including Stephen Wolfram, Will Shortz,  Dale Seymour, John Conway and many others. 

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GV. Three Quick G4G9 Puzzles From Ed Pegg

We’re at The Gathering For Gardner, G4G9, and catch up with Ed Pegg of and numerous other exploits; Ed gives us three quick puzzles to chew on– answers at his website. 

@MathFactor is tweeting pictures and more, and more short podcasts from the festivities!


(And Jeff didn’t make it! Rats!)


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