Linear Algebra Jokes

Apr 2021

How these jokes came to be

In spring 2021, I taught a linear algebra class at Khan Lab School. To motivate students to come to office hours, I created a custom joke every week. I've reproduced these jokes below. All lecture videos available here.

The jokes...

Why did the man not want to get onto the bus crowded with passengers who weren't wearing masks? Because it was a dangerous vector space.

Why did mathematicians at Moderna use linear algebra to help develop a vaccine? Because they needed to make it injective.

What do you call an eigenvector that scales to make 100 million vaccines? A Bidenvector!

How did Harry Potter know where to go on the map of London to buy his school supplies? He Diagonalleyized the map!

What did the teenage eigenvector tell her overprotective parents? Leave me alone, I need my eigenspace!

Why was the patient angry at the orthodontist? When she took off her braces, her teeth were all at 90° angles.

The mathematician from Mexico really likes linear algebra. His favorite part is the Span-ish.

Did you hear why Jeff Bezos is leaving Amazon? Some people say it’s because he wasn’t good enough at linear algebra. But at the press conference, Bezos said that was a basis-less claim.

Why did the British outlaw studying linear algebra in 1776? Because they didn’t want any of their colonies to declare Linear Independence.

Gauss’s crew team won first place two years straight, but the third year he was injured and off the team. Why did the crew team stop winning? Because after Gaussian elimination, they only had tiny, reduced rows!

What do you call the nest of an ant colony that has dug really deep into the ground? An in-very-ant subspace!

The little eigenvector wanted to be an astronaut when he grew up, but he couldn’t pronounce such a long word. What did he say instead? When I gwow up, I geh in spaaace! (eigenspace)

My favorite: Why did the eigenvector girlfriend break up with her eigenvector boyfriend? Because when she discovered their eigenvalues were fundamentally different, she knew she needed her linear independence.

Hey [name], did you know your refrigerator is running? Well you better go and catch it!

Okay, but getting serious here. How do you put a linear algebra professor into the refrigerator? Step one: open the door. Step two: put him in. Step three: close the door.

Okay, now say it’s an hour later. How would you put an inner product in the fridge? Open the door. Take the professor out. Put the inner product in. Close the door.

Now, how would you put in a magnet? No, no, no! You don’t put magnets in the fridge! You stick them on the door. And anyway, the inner product is inside so we don’t currently have any notion of magnet-tude.

All right, now let’s say there’s a fisherman far away in the Atlantic ocean. Why can’t he catch any fish? Because the inner product is still in the refrigerator! And how can you expect an angler to catch fish if he has no sense of angle?

Okay, finally some students are waiting to join their linear algebra class, but the teacher is late: one minute, three minutes, five minutes. Why doesn’t the teacher show up? Because you all put him in the fridge, remember?! He’s practically hypothermic. Way, way too cool for school.

Hey guys, I’ve really enjoyed teaching linear algebra, so I’ve decided to adopt a new nickname. Want to know what it is? You can call me LA Laker... for linear algebra Laker!

What did the Salem Witch Trials have in common with linear algebra? The Puritans were just applying the Spectral Theorem: if she doesn’t look normal, then burn her alive!

You all know what to call a linear operator which equals zero when raised to a high enough power: nilpotent. But what do you call a fish that can breathe well? Gilpotent. What about a costly repair or a drug that’ll put you right to sleep? Billpotent and pillpotent! An effective refrigerator or a loud, sharp scream? Chillpotent and shrillpotent. An herb to seriously spice up your eggs? Dillpotent. And, finally, a mountain? Hillpotent.

It's a little known fact that Michael Jordan owns a parrot. Why is this parrot so skinny? Because its name is Poly No Meal, and it's a minimal Poly No Meal at that! This parrot is also the best at dunking, no doubt because it's in Jordan Form.

Why did the detective abandon the investigation into the crime of the diagonal matrix? Because when he added everything up, he found only trace amounts of evidence.

If you’re Sheldon Axler, what do you say at the steakhouse? I’d like my steak... done right.

Jokes about other areas of higher math

Abstract algebra: In the abstract algebra class, what do they call the student who scores highest on the second midterm? Lord of the Rings.

Field theory: Galois died in a duel at the age of 20. It wasn’t his field of expertise.

Markov chains: A drunk man will always find his way home, but a drunk bird may be out of luck.

Topology: What is a topologist’s favorite breakfast? Froot Loops with a donut and coffee mug, although she can’t tell the difference.

Multivariable calculus: What did the multivariable calculus professor say to his students before the final exam? No pressure, but the Stokes are high.

Measure theory: The measure theorist paid the baker in pennies, nickels, dimes, quarters, dollars, fives, then tens until he was done, rather than the price of each item one after the other. What did the measure theorist purchase? Lebesguels!

Graph theory: What did the graph theory professor say to his students after they all aced their final exam? Congraphulations!

Theory of computation: What did the programmer say when faced with solving a size n travelling salesman problem for a grid of scenarios of length m and width a? O(man!)

And finally... a math rap!

Uh, uh. Here’s a math rap.
Uh, uh. When I’m done please clap.

Two variables in a function I got
Two numbers in the output slot.
How do I take a derivative
What numbers must I give?
Turns out the answer’s slick
Just use a square matrix.
That’s right, a linear map
Straightaway fills in the gap.
This local approximation
Is an epsilon-delta generalization.
Nudge a function to see it move
And use open sets this to prove.
From there is the question of integration
Where Stokes gives us cause for elation,
Since functions on boundaries evaluated
Equal derivatives everywhere else calculated.

Uh, uh. Movin’ on.

See, I got a problem with integration.
What if my dart can’t decide its location?
Is it rational, or is it not?
This is getting steamy, the debate is hot.
To the rescue is the man Lebesgue.
His measure is everyone’s fav.
It says the length of a set
Is the infimum of its covering boxes.
With it, our integral we can get
No worries about paradoxes obnoxious!

Uh, uh. Movin’ on.

You might wonder what nodes and edges can do.
Just about anything: it’s true!
We got paths and cycles and neighbors and degrees,
Minors, marriage, coloring, and spanning trees!
Turns out any preferences are okay
You can always get matched with no foul play.
So it’s a whole wide world to explore,
And any map needs colors just four.

Uh, uh. Movin’ on. Uh, uh. Last one!

So you’re name is Alan Turing
And your mind is brewing.
You have a model for computing
With a tape, head, and moving,
Its power is fabulous,
Same as lambda calculus.
But though it’s miraculous,
Its reach isn’t limitless.
See, the Halting Problem proclaimed
Computers are strictly maimed
Of the wondrous ability
To serve just any utility.
Thus to solve a given task,
We must ask
How long it will take
Or whether an algorithm is even possible to make.
And with big O notation
We can quantify duration.
Is it fast to solve, or merely fast to check?
If one then joy, if the other I’m a wreck.
But if you prove P = NP
You will earn a lot of money.

Uh, uh. With that the rap ends.
Uh, uh. Go learn math, friends.