ELI5: Explain Like I'm 5

Zariski–Riemann space

Imagine you have a big piece of paper and you want to draw a shape on it. You can draw lots of different shapes, like a triangle, a circle, or a square. And you can make the shapes big or small, or move them around on the paper.

Now let's say you want to draw lots of shapes and put them together in a big picture. But you don't just want any old shapes, you want shapes that have something in common. Maybe you want all the shapes to have the same number of sides, or the same color.

That's kind of what the Zariski-Riemann space is like. Instead of shapes, we're talking about equations. An equation is like a rule that tells you which points on a graph are part of a shape. For example, the equation x + y = 5 gives you all the points on a graph where the x-coordinate and y-coordinate add up to 5.

In the Zariski-Riemann space, we're interested in equations that have something in common. Specifically, we want equations that give us information about curves. A curve is just a line that wasn't drawn with a ruler - it can be wavy or curly or have lots of corners.

So in the Zariski-Riemann space, we start with a bunch of equations that describe curves. But we don't just want any old equations - we want equations that work together in a certain way. This is where the Riemann surface comes in.

The Riemann surface is like a special type of graph that can help us understand how equations work together. It has some special properties that make it very useful for this purpose. If we take our equations and put them into the Riemann surface, then we get a picture of how all the curves look together.

But we're not done yet! The Zariski-Riemann space is actually a little bit more complicated than just the Riemann surface. We also have to think about something called the Zariski topology. This is like a special way of looking at the Riemann surface that helps us understand more about how the equations are related.

When we put everything together - the curves, the Riemann surface, and the Zariski topology - we get the Zariski-Riemann space. It's like a big, complicated picture that tells us everything we could want to know about how equations for curves work together. But just like with our initial shapes on paper, we can play around with the equations to create new pictures and explore all the different possibilities.