d/dy

Binary Puns

2008-03-03T09:26:00.001-05:00

Via my co-workers Ben and Craig:

http://www.threadless.com/profile/685211/bhs/slogans
http://www.thinkgeek.com/tshirts/frustrations/5aa9/

Hee hee.

Why we should hang out: A Mathematical Proof

2007-11-17T14:34:00.000-05:00

from Craig's List:
http://www.craigslist.org/about/best/aus/419154651.html

The saddest part is that I've seen most this proof before, and I totally remembered that choosing the best person after (1/e) * n yields the maximal expected utility.

Real World Math Skills

2007-10-25T18:55:00.000-05:00

During the War, a mathematician, a chemist, and a mechanical engineer are captured by the enemy. They're thrown into three jail cells in a remote part of the enemy base, and quickly forgotten. A month later the jailer remembers that these three prisoners haven't been fed in a month, and goes to check on them.

In the first jail cell, he finds a rudimentary lever and wedge on the floor. The mechanical engineer had pried the cheap cell bars apart, and escaped handily.

In the second jail cell, he finds a puddle of acid: acid that the chemist had poured on the cell bars to free himself.

In the third jail cell, he finds the mathematician's rotting corpse. Next to the body, there's a piece of paper. He reads it. It says: "Assume that I have the key to the cell..."

More Statistical Error

2007-10-25T08:36:00.000-05:00

From a colleague:

Two statisticians are at a shooting range.

The first statistician misses the target by 10 feet to the left.

The second statistician misses the target by 10 feet to the right.

They cheer.

Another Statistician Joke

2007-09-13T00:11:00.000-05:00

Another popular statistician joke recently appeared in this article on Slate. Jordan Ellenberg tells it so well that I'll just quote him verbatim:

10 statisticians in a bar. Ted Turner walks in. The statisticians start to whoop and holler. "What's going on?" asks Turner. One statistician explains, "On average, we just got a whole lot richer!"

Oh, Statisticians

2007-09-10T22:03:00.001-05:00

Statisticians are to math what dentists are to the medical profession. Everyone knows that statisticians aren't real mathematicians, but we treat them like it to boost their self-esteem. And statisticians—like blondes—are great targets for jokes.

Two statisticians are on an airplane. Suddenly, they hear a huge crash. They hear the pilot over the loudspeaker:

"Attention all passengers, we have lost an engine. Fortunately, we should be able to make it to our destination with our three remaining engines. Estimated flying time is now at about 4 hours."

The staticians hear this and are put at ease. They continue to talk together when they're interrupted by second crash, and the sound of the loudspeaker again.

"Attention all passengers, we have just lost a second engine. We should still be okay on 2 engines, but we probably won't reach our destination for at least 6 hours."

Well, the staticians have time to burn and books to read, so they don't bother worrying about this new development. Suddenly, there's another crash, and the pilot's anxious voice comes over the loudspeaker:

"Attention all passengers, we're now flying with only one engine left. It will take us at least 8 hours to reach our destination now."

One statistician turns to the other and says,

"Gee, if we lose one more engine, we'll be flying all night!"

Chemistry Jokes: Not As Good As Math Jokes

2007-06-08T22:30:00.000-05:00

A ways back, I was hanging out with some chemistry grad students at a Yale bar, so of course I had to tell them my favorite chemistry joke:

Heisenberg is carelessly speeding down the highway when he gets pulled over by a cop.

The cop walks up to the driver side window and asks him, "Sir, do you know how fast you were going?"

Heisenberg responds: "No, but I know exactly where I was!"

Well, the grad students liked that one, and returned the favor with one of their own:

A guy walks into a bar. He asks the bartender, "I lost an electron here last night, have you seen it?"

The bartender shakes his head and says, "Nope. Are you sure you lost it?"

The guy responds, "Dude, I'm positive!"

Bertrand Russell is Awesome

2007-05-31T17:46:00.000-05:00

I've heard this joke a few times. But my colleague Adam re-told it to me recently, and he has the best delivery I've heard yet.

Bertrand Russell once taught a class in logic. He was trying to teach his students why inconsistency was important: because you can prove that anything is true if you start from false assumptions.

One of his students interpreted that as a challenge. "Given that one equals two, prove that you're the pope," he shouted.

Russell immediately replied, "Nothing could be simpler. The pope and I are two, and two equals one, so the pope and I are one. Therefore, I am the pope."

The End of Pi

2007-05-13T23:41:00.000-05:00

There's a winery in Napa Valley that boasts its own art museum. The owner bankrolls a handful of artists, then dedicates a gallery in the winery to their works. One artist uses his gallery space to pay homage to pi, with a 6-foot high LED display that shows the first 500 digits of pi, one at a time, over and over again.

Next to the display, there's a plaque with an explanation of the significance of pi, for those who are not mathematically inclined. This plaque informed me that mathematicians had been studying pi for a long time, that they believed this number had no end, and this bit of trivia:

Governments and universities around the world run computers to calculate the digits of pi, in the hope that they will someday find an end to this number.

My fellow wine-taster Bay saw this, pointed at it, and yelled: "Yeah...if they're STUPID!"

I don't mind so much when people completely fail to grasp irrational numbers. But if you're going to build a modern-art sculpture in pi's image, you probably should do 5 minutes of worth of research on it.

How Abraham Deals With His Computer

2007-05-09T01:04:00.000-05:00

from Garrison Keillor's 8th annual joke show:

Abraham is installing Windows Vista on his computer, when his son Cain enters the room and says to his father, "Dad, you can't install Windows Vista. Your computer doesn't have enough memory!"

Abraham answers, "Don't worry, son. God will provide the RAM."

Gender Equality in Math Jokes

2007-05-07T22:51:00.000-05:00

There are great mathematical pick-up lines for females too. We came up with this one the other night:

I wish I were e^x, so that you could take my derivative all night long!

...OK, I'll stop.

A Refined Mathematical Pick-Up Line

2007-05-03T20:14:00.000-05:00

I'm not sure whether this is an improvement or not:

I wish I was a Taylor approximation, so that I could lie tangent to your curves, then diverge a bit on the weekends.

Speaking of innuendo, the condom posters that they're posting around NYC are hilarious. Take a look:

The Mathematician and The Plumber

2007-05-03T00:11:00.000-05:00

The Aristocrats is a brilliant movie. On the one hand, it's about the nature and art of a good joke, and on the other hand, it's depraved.

Roger Ebert's review is also brilliant, in that eloquently Ebert way where you can agree with his analysis but disagree with his opinion. He breaks it down like this—there are two kinds of jokes: short jokes and long jokes. A short joke is like a good pick-up line. Because it has to end before your audience realizes that it's a joke, it packs everything in the punchline and whirls to that punch in a sentence or two.

But for a long joke, the punchline doesn't matter. It's just an artifact of the form of the joke, like some plastic-wrap packaging to be thrown away when you're done. The real joke is in the telling, in the construction, in the precariously tall tower of cards that you have to build up to get there. A good long joke makes sense during the telling, yet completely contradicts itself when you look at it from any other direction, like a Kurt Vonnegut novel.

The geometer Peter Doyle once told me one such long joke. I've condensed it here for easier reading:

Once upon a time there was a mathematician. His toilet was clogged. So he called the plumber. The plumber arrived later that evening, unclogged the toilet in 15 minutes, and handed the mathematician the bill. The mathematician looked at the bill and shouted: "Great scott! What a bill! You plumbers must make a fortune charging people this much. Do you mind if I ask how much you make?"

The plumber doesn't mind. He grins and names his salary.

The Mathematician: "That's more than I make. And it looks a lot easier than theoretical mathematics."

The Plumber: "Well, friend, you sound eager, so I'll give you a tip. The plumbing business is swell. And my foreman needs more men for the job. Tell him I sent you, and you can see for yourself what the work is like. One thing though: don't tell him you're a mathematician. He hates elitists, and he won't hire anyone with higher than an 8th grade education."

Well the mathematician was as serious as he claimed. The next day he did indeed go to see the plumber's foreman. By pretending to be a middle-school drop-out, he got the job easily. And lo! It was better than he had hoped. He found himself with better pay, fewer hours, and more respect than he ever had as a theoretical mathematician.

The mathematician worked many years as a happy plumber. The plumbing industry flourished, and one day the foreman decided that his plumbers really had to be at a 9th-grade level in order to remain competitive in this rapidly-growing field. He hired several private tutors, and required his plumbers to attend night classes.

On the first day of class, the math teacher was trying to gauge what his students knew. He singled out one plumber and asked, "Do you know the formula for the area of the circle?" Of course, the tutor had picked our mathematician, and like any good mathematician, he responded, "No. But I know how to derive it." "Derive it for me then," challenged the teacher.

So the mathematician went to the blackboard and began to compute the area of the circle as any good mathematician would. He wrote out the double integral with respect to x and y, computed the Jacobian with respect to r and theta so that he could perform a change of basis in terms of polar coordinates, then evaluated the double integral. And came to the solution -π*r².

"Wait!" said the mathematician right before he announced his answer. "That can't be right!" He began to check his work, looking for where the negative got introduced. But he couldn't find his mistake. At last he threw up his hands, erased his computation, and started over again. He quickly set up the double integral, did the change of basis to polar coordinates, and simplified. And again he arrived at -π*r² !

By now the mathematician was frantic. How could he have gotten such a ridiculous answer twice? Had his math skills really gotten so bad? He wildly looked to the teacher, but the teacher knew nothing of multi-variable calculus, and had no idea what was going on. Then he looked to the class...and noticed something quite odd.

The eyes of every plumber were fixed upon him! The class was anxiously, quietly trying to get his attention without alerting the teacher. Each one had his hands cupped around his mouth, and they were all whispering the same words over and over again in unison. Slowly, he leaned in to hear better. And this is what he heard:

"You forgot to take the absolute value of the Jacobian!"

A Mathematical Pick-Up Line

2007-05-01T09:53:00.000-05:00

I wish I was a derivative, so that I could lie tangent to your curves.

Grapes and Lemons

2007-04-30T22:21:00.000-05:00

When most people need answers, they ask Google. So where do Google engineers get answers to our questions? Well, that's why we have whiteboards.

At Google, a whiteboard is a communal free-association machine. For example, suppose I were to write on the whiteboard, "What is the answer to life?" Within 5 minutes, someone would walk by and write below it, "42." That's just how whiteboards work.

A few months ago, on my way to get a cup of coffee, I stopped to write this:

Q: What's purple and commutes?

In the time it took me to fill my cup and return, someone had already written below it:

A: An Abelian grape.
Q: What's yellow and equivalent to the Axiom of Choice?

Cute. But no time to respond; time for meetings. The next time I walked past the whiteboard, a third person had written below that:

A: Zorn's Lemon.
Q: What's an anagram for Banach-Tarski?

Now I had never heard of that last joke. Fortunately, I learned the answer an hour later, from a fourth person's handwriting:

A: Banach-Tarski Banach-Tarski

Then, below that, in a fifth style of handwriting:

I don't get it. What's Banach-Tarski?

And you can probably guess what was below that:

A: Google it

And that's how Googlers ask questions. Credit goes to Michael in the comments for reminding me of that exchange.

Airport Security Likes Google Too

2007-04-22T19:29:00.000-05:00

One of the perks of working at Google is that something like 25-30% of the company budget goes towards t-shirts like this one.

In any case, I was wearing one such Google NYC t-shirt when airport security stopped me with this great one liner:

So you work at Google? Wouldn't it be ironic if we searched you?

An Engineer, A Mechanic, and a Computer Scientist

2007-04-21T13:29:00.000-05:00

Eric's joke reminded me of this one, via Kris McNall:

An engineer, a mechanic, and a computer scientist are driving in a car. Suddenly, the brakes stop working. The car starts rolling down the hill at a terrifying rate, and all 3 scream for their lives. But they get lucky: the car gets to the bottom of the hill safely, and eventually rolls to a stop.

All 3 get out, and the mechanic looks under the hood for about 5 seconds.

The Mechanic: "The problem is obvious! We're missing a Johnson rod. Each of you give me $500, and I'll walk to the nearest garage and get a replacement."

The Engineer: "What? How can you possibly know that? We must completely take apart the car and stress test each individual component to determine the exact point of failure."

Well, the engineer and the mechanic argue for a bit. And then they notice that the computer scientist hasn't been participating in the debate. He's been pushing on the car's front bumper. They ask him why.

The Computer Scientist: "I'm going to push the car back up the hill, get inside, and see if it does it again!"

Mayonnaise and Theoretical Computer Science

2007-04-21T13:26:00.000-05:00

I ordered a Philly cheesesteak at the NIST cafeteria on Wednesday. The woman behind the grill shouted, "You want mayonnaise on that?" What? I didn't know people ever had mayonnaise on that. I told her so. She furrowed her brow. "You're not from around here are you? Yeah, I can always spot the foreigners." She slows down her speech at this point, just in case I might have trouble speaking English. "In America, we eat our cheesesteaks with mayonnaise."

The guy from Jersey standing next to me almost dropped his tray. He didn't completely stifle his laughter. But he tried.

At this exact moment, Eric Norman sidled up next to me and asked me this:

Q: What's the difference between a mathematician and a theoretical computer scientist?

A: A mathematician knows how to prove things without using induction.

d/dy

2007-04-20T20:47:00.000-05:00

Last weekend I told a joke.

I told this joke to a bubble-headed girl, in a white blouse, holding a glass of red wine. You can probably guess where this is going. At the time, this seemed like an appropriate joke, since the girl had studied engineering in college:

e^x is at a party. But he's kind of depressed, so he sulks in the corner and drinks by himself. The host sees him and asks, "What are you doing all alone in the corner? You should be having fun! Mingle! Socialize! Integrate!"

e^x responds: "It wouldn't matter."

Now, this isn't a very good joke. It's actually a pretty bad joke, even in the range of jokes about e^x. (There are certainly better jokes about e^x.) But the girl snorted with laughter, and spilled the wine all over herself. So for the rest of the night, every time she met someone new, she would have to explain how she got to be soaked in wine, which of course means that I had to tell the joke many times over.

I'm sorry to say that no one else understood what the hell the joke was about.

Perhaps they would have gotten it if I had told a superior e^x joke, like this one:

Three no-good, divergent functions are hanging out on the street corner: x, x², and e^x. They spot a differential operator walking towards them. "Yo, man, we better get out of here," x says to x², "before he differentiates us down to a constant."

e^x, cool and collected, talks back, "Dudes, chill! I'm e^x. He doesn't scare me. You just wait here and I'll take care of this."

So x and x² hang back. e^x walks directly into the path of the differential operator, holds out his hand, and growls, "Hey man. I'm e^x. What the hell are you doing on my turf?"

The differential operator nonchalantly looks him up and down, then responds, "Nice to meet ya, e^x...I'm the differential operator with respect to y."

Now that's an e^x joke worth ruining a shirt over.

Peter Winkler once said that normal people exchange jokes, and mathematicians swap puzzles. OK, but I submit that mathematicians have some great jokes too. And I need a central place to dump them, and a blog is as good as any. I'll cite my sources when I can.

The e^x jokes are courtesy of Bart Blackburn.