ELI5: Explain Like I'm 5

Affine Grassmannian

Okay, little one, let's talk about something called the affine grassmannian!

Imagine you have a bunch of lines on a piece of paper. You can move those lines around, stretch them out, and rotate them, but they'll still be lines. Now imagine you have another group of lines that are kind of like shadows of the first group – they look similar but they're not exactly the same. You can move them around, stretch them out, and rotate them too, but they'll still be shadows.

The affine grassmannian is a way of thinking about these groups of lines and their shadows in a fancy math way. It's like a special kind of map that tells you all the different ways you can move and stretch and rotate the lines and their shadows so that they still look the same.

Now, let's add one more thing. Imagine you have a bunch of points on the paper, too. They're like little dots that the lines and shadows pass through. The affine grassmannian can also tell you all the different ways you can move and stretch and rotate the points and the lines and their shadows so that everything still looks the same.

So basically, the affine grassmannian is a kind of special map that helps you understand how you can change lines and shadows and points so that everything still looks the same. It's useful for lots of things in math, like studying curves and shapes, and even for things like coding and computer science!

Did that help you understand what the affine grassmannian is?