ELI5: Explain Like I'm 5

Stanley symmetric function

Okay kiddo, have you ever played with toys that looks the same no matter which way you turn them? Like a square or a diamond? Those are called symmetric shapes because they have the same pattern on both sides.

Now imagine we have a bunch of letters, like A, B, C, and D. We can use these letters to create something called a "partition". This just means we group the letters into different sets. For example, we could make the partition "AB|CD", which means we have two sets - one with the letters A and B, and another with the letters C and D.

The Stanley symmetric function is a fancy way of counting all the different ways we can make partitions using those letters. It tells us how many different ways we can group the letters into sets so that they are symmetric.

Let's say we have four letters - A, B, C, and D. There are five different ways we can make partitions that are symmetric, using the Stanley symmetric function. These are:

- {AB,CD}
- {AC,BD}
- {AD,BC}
- {A,B,C,D}
- {}

The curly braces {} represent an empty set, which is also a way to partition the letters symmetrically.

So basically, the Stanley symmetric function helps us count how many different ways we can group objects into symmetric sets. It can get pretty complicated with lots of objects and different ways to group them, but that's the basic idea.