ELI5: Explain Like I'm 5

Closed graph property

Okay kiddo, let's start with graphs. Do you know what a graph is? No? Well, a graph is like a picture that shows lines and points. The lines connect the points together and the points are sometimes called vertices.

Now, let's talk about closed graph properties. This is when you have a special kind of graph called a mathematical function. A mathematical function is like a machine that takes in a number and spits out another number.

A closed graph property means that if you draw a line between any two points on the graph of this function, the line will always stay on the graph. That means the graph is "closed" to any lines that try to leave it.

So, let's imagine you have a graph of a function that draws a line going up and to the right. If you pick any two points on that line and draw a line connecting them, you'll find that the new line also goes up and to the right. It doesn't curve away from the original line or go backwards, it stays on the graph and that's what makes it a closed graph property.

Now, why is this important? Well, mathematicians like to study functions with closed graph properties because they can tell us a lot about how the function behaves. It's kind of like looking at a map where all the roads lead to the same place. That tells us something about where we are and where we can go.

So there you have it, closed graph properties are all about graphs that don't let lines leave them. It's a cool thing that helps us understand functions better.