Okay, let's imagine you have a bunch of boxes of different sizes and shapes. You want to figure out which boxes can fit inside of other boxes. To do this, you need a way to compare the sizes and shapes of the boxes.
The compact-open topology is like a way to compare the sizes and shapes of sets. A set is just a collection of things, like the boxes. The compact-open topology is a way to compare how big one set is compared to another set.
To use the compact-open topology, you need to have a way to measure the distance between sets. This distance is called the "Hausdorff distance". It's like measuring the distance between two boxes by using a tape measure.
The compact-open topology tells you which sets are closer together and which sets are farther apart. If two sets are very close together, it means that they are similar in some way. For example, two boxes that are very similar in shape and size would be very close together.
The compact-open topology is useful in lots of areas of math, like topology, geometry, and calculus. It makes it easier to solve problems and see patterns in sets of things. Think of it like a helpful tool that makes it easier to compare and analyze sets of things!