ELI5: Explain Like I'm 5

Quasi-Fuchsian group

Alright, so let's talk about "quasi-fuchsian group" in a way that even a 5-year-old can understand.

Have you ever played with a rubber band? You know how you can stretch it and squash it and twist it into different shapes? Well, a quasi-fuchsian group is like a group of rubber bands that have been stretched and twisted in a special way.

Imagine that you have a big flat surface, like a piece of paper, and you stick a bunch of rubber bands onto it. Now, if you try to stretch and squash those rubber bands in any way you want, you might end up with a big mess that looks nothing like the original shape. But if you're careful about how you stretch and squash the rubber bands, you can actually make them form a really cool pattern on the paper.

That's sort of what a quasi-fuchsian group does. It takes a bunch of "rubber bands" (which are actually lines in a special kind of geometry called hyperbolic geometry), and carefully stretches and squashes them so that they form a really beautiful and symmetric pattern on a flat surface.

But here's the tricky part: this pattern isn't just any old pattern. It's actually a very special kind of pattern called a "Fuchsian pattern," named after a mathematician named Lazarus Fuchs. Fuchsian patterns have the property that they repeat themselves in a regular way, kind of like how wallpaper patterns repeat themselves.

So a quasi-fuchsian group is a group of "rubber bands" that have been stretched and squashed in a way that makes them form a beautiful, repeating Fuchsian pattern on a flat surface. It's kind of like magic, but with math instead of a wand!