One More Epicycle

Yesterday there was a very good talk on the computability of Julia sets at the dynamics seminar.  The presenter was originally from Canada — well, Toronto anyway — and was an excellent speaker; I don’t know if those two are related, I’m just sayin’, is all.  At one point, he tried to establish how much the audience knew about Julia sets and how much he’d have to explain.  Almost all of the audience said they knew what they were, which was good because then he could concentrate on the relevant points and not give a minitutorial.

He couldn’t help himself from asking one test question of the crowd, though:

“What’s your favourite Julia set?”

“The circle,” said one professor.

[For nonmathematicians: at this point the room erupted in laughter.  --ed]

“Good answer,” was the reply.

True story!  The seminar was given by Michael Yampolsky of the U of T and ETH Zurich, describing neat work he’s done with his grad student, and some counterintuitive results they’ve found.

There’s a number of math jokes — rimshot! .. ? .. tough crowd.. — all involving a mathematician solving a problem by assuming he has one of the needed items, such as a can opener or a ladder, or reducing it to a previously solved problem. (For a detailed discussion of math humour, you can read this article by Renteln and Dundes.)

For example (based on the version here):

A physicist and a mathematician are sitting in a faculty lounge. Suddenly, the coffee machine catches on fire.

The physicist grabs a bucket and leaps towards the sink, fills the bucket with water, and puts out the fire.

The next day, the two sit in the same lounge, and once again, the coffee machine catches on fire.

Remembering what happened before, the mathematician stands up, gets a bucket, and then hands the bucket to the physicist.

Okay, so it’s not exactly xkcd, but don’t blame me: I didn’t come up with the joke, I’m just retelling it.

A certain mathematician friend of mine has taken this motif to a new extreme, and in doing so proved that this line of gentle mockery is entirely justified.

He’s familiar with the Web’s hat-tip conventions, under which when you come across something interesting you typically provide a link not just to whatever it is but to whoever you learned about the whatever-it-is from. (Cosh’s suggestion to use the thorn symbol doesn’t seem to have caught on, as medieval-cool as it is, so I just say “hat-tip” or “via”.)

But what if you’re posting recipes given to you by someone in real life, who doesn’t have a Web page?

A physicist, faced with the same situation, might have concluded that the convention doesn’t apply and simply mentioned the name. When a formula doesn’t give a useful answer in some situation, you usually decide that it must not work in that regime, and move onto something else.

Said math guy instead decided to set up a blog for the person in question, thereby reducing the problem to one he knows how to solve!

*shakes head in bemused disbelief*

You know, I miss Kingston a lot, but I miss the people more. This is one of the reasons why.

In his honour, some math jokes I hadn’t heard before:

In a dark, narrow alley, a function and a differential operator meet:

“Get out of my way – or I’ll differentiate you till you’re zero!”

“Try it – I’m e^x…”

Same alley, same function, but a different operator:

“Get out of my way – or I’ll differentiate you till you’re zero!”

“Try it – I’m e^x…”

“Too bad… I’m d/dy.”