ELI5: Explain Like I'm 5

Stirling polynomial

Imagine you have a box of toys and you want to count how many different ways you can arrange them. For example, if you have three toys labeled A, B, and C, you can arrange them as ABC, BAC, ACB, CAB, BCA, and CBA. There are a total of 6 different ways to arrange these three toys.

Now, let's say you have more toys, like four toys labeled D, E, F, and G. You want to find out how many different ways you can arrange these four toys. You can do this by finding all the possible arrangements and counting them. The number of arrangements is called a Stirling polynomial.

To find the Stirling polynomial, you can use a formula. Let's say you want to find the Stirling polynomial for arranging four toys. The formula is:

S(4, 1) = 0
S(4, 2) = 0
S(4, 3) = 6
S(4, 4) = 24

This formula tells you that there are 0 ways to arrange four toys in groups of one, 0 ways to arrange them in groups of two, 6 ways to arrange them in groups of three, and 24 ways to arrange them in groups of four.

The Stirling polynomial helps us understand the different ways we can arrange objects. It can be used in many different areas of mathematics, such as combinatorics and probability.