9 - Set Theory #
The, uh, study of sets. It’s not as boring as it sounds, I swear.
Set theory is pretty boring. Yes, it brings about ideas of infinity, Sets of numbers (integers, complex numbers, etc.) but frankly, unless you’re really into math’s nerdy bits and trying to understand the nature of mathematics and all that jazz, there’s really only a few bits you need to understand:
The parts that matter: #
This is the basic way we’ll visualize set theory. You’ve got a domain (the box) and sets (the circles). The domain is everything relevant to the problem. Maybe it all numbers, maybe it’s just the integers, maybe it’s the different species of fish in the ocean. Whatever.
Sets are just collections of objects. Maybe you’d have a set of ‘all even numbers’ maybe you’d have ‘fish with blue scales’. Some sets may overlap, some may not.
There’s also a special set called the empty set, written with ∅, which is the set that contains nothing. We’ll come back to this.