ELI5: Explain Like I'm 5

Degeneration (algebraic geometry)

Degeneration in algebraic geometry means the process of making something complicated simpler by slowly changing it into something easier to understand. Let's say you have a big, complicated math problem that you're not sure how to solve. You start by breaking it down into smaller, more manageable parts, and then you gradually simplify each part until you have a solution.

Now imagine you have a geometrical shape, like a curve or a surface, that is very difficult to study because it has too many complex features. Degeneration allows you to transform this shape into a simpler one by introducing a parameter that slowly changes its properties, until you end up with a limit shape that is easier to analyze.

Think of a caterpillar turning into a butterfly. The caterpillar is the complex shape that is hard to understand, but as it undergoes metamorphosis, it gradually transforms into a simpler and more beautiful creature. In the same way, degeneration allows us to study complex geometrical objects by turning them into simpler ones that we can easily handle.

To summarize, degeneration is a technique that algebraic geometers use to simplify complex shapes by gradually transforming them into simpler ones through the introduction of a parameter that controls the pace of the transformation.