Fredholm theory is a way to study a special kind of math problem where you have a bunch of rules and you want to find out if there is an answer that follows all the rules. Think of it like a puzzle that you want to solve.
Now, let's say you have a lot of different rules, but you can't figure out if there is an answer that follows all of them. This is where Fredholm theory comes in. It helps you figure out if there is a solution to your puzzle, and if so, what that solution would look like.
To make this easier to understand, let's think of an example. Imagine you have a bunch of equations that you need to solve, but you're not sure if there is a solution that works for all of them. Fredholm theory helps you figure out if there is a solution, and if there is, how to find it.
So, in summary, Fredholm theory is a way to figure out if there is a solution to a complicated math problem that follows all the rules given, and if so, how to find that solution. It's like a cheat code for puzzles!