ELI5: Explain Like I'm 5

Eisenbud–Levine–Khimshiashvili signature formula

Have you ever heard of signatures? They are like a special code that tells you some important things about a shape. For example, if you draw a circle, it has a signature that tells you whether the circle is going clockwise or counterclockwise.

Now imagine you have a really complicated shape, with lots of twists and turns that make it hard to figure out its signature. That's where the Eisenbud-Levine-Khimshiashvili (ELK) formula comes in!

The ELK formula is like a magic wand that helps you find the signature of these complicated shapes. It works by breaking the shape down into smaller, simpler pieces (kind of like breaking a big puzzle down into smaller pieces).

Then, for each simple piece, the ELK formula gives you a special number called a "contribution" that tells you how that piece affects the overall signature of the shape. You add up all the contributions from all the simple pieces, and voila! You have the signature for the whole shape.

This might sound a little complicated, but it's actually really useful for mathematicians who study shapes and the ways they can be twisted and turned. By using the ELK formula, they can learn more about these shapes and how they behave - just like you can learn more about a circle by studying its signature.