# Mathematicians Play “Set”

Analyst: Set!
Everybody: Where?
Analyst: How should I know? I have an existence proof. It’s not constructive.

Topologist: Set!
Everybody: That’s not a set. You have two diamonds and a squiggle.
Topologist: I don’t get what you’re saying.
Everybody: See? The shapes have to be all the same, or all different.
Topologist: Like… different genus?
Everybody: No, see, that’s a diamond. That’s a diamond. That’s a squiggle.
Topologist: Your mouth is making sounds but none of them seem to mean anything.

Category Theorist: Set!
Everybody: Where?
Category Theorist: See, here’s a set that fails because of the textures. Here’s a set that fails because of the colors. Here’s a set that fails because of the numbers. And all three of them fail because of the shapes.
Everybody: That’s just a bunch of failed sets.
Category Theorist: Only if you look at the wrong level of abstraction.

Probability Theorist: Set!
Everybody: Wait, what?
Probability Theorist: The expected number of sets is almost three. The probability of at least one is nearly 0.97.
Everybody: But we haven’t dealt the cards yet.
Probability Theorist: Exactly. Once you sample from the distribution, all bets are off.

Logician: Set!
Everybody: Where?
Logician: It’s the set of all sets that don’t contain themselves.
Everybody: That’s literally all sets in this game. None of them contain themselves.
Logician: Perfect! Then give me all the cards.
Everybody: “All the cards” isn’t a set.
Logician: Hey, I understand the temptation to define “set” narrowly, but I worry this axiomatization isn’t going to get you anywhere.

Data Scientist: Set!
Everybody: Where?
Data Scientist: Two solid squiggles in each color.
Everybody: Um, none of those cards are showing.
Data Scientist: Okay, the underlying data may have some issues, but my analysis is still sound.

Set Theorist: Set!
Everybody: Okay, before you say anything, is it the empt—
Set Theorist: It’s the empty set!

## 4 thoughts on “Mathematicians Play “Set””

1. Christine Luketic says:

I enjoy your Math with Bad Drawings everytime I read them. They bring an authentic smile to my face, and I appreciate that.

2. Charlie Kelly says:

I bought the card game SET! in 1995. What a wonderful game for all ages. Thanks for the memory and the humor.

3. Sarah says:

I needed this today… I’ve been playing Set with my students, and they (unknown to themselves, of course) seem to be topologists.

4. Yes another roleplaying post! (Really enjoyed the splitting the check post)