Closed Set

A closed set is a collection of points in mathematics that includes all its boundary points. This means that if you take any point that is close to the edge of the set, that point will either belong to the set or be part of the boundary itself. In simpler terms, imagine a circle drawn on a piece of paper: the area inside, along with the boundary line, forms a closed set. It helps mathematicians understand different properties in spaces, such as limits and continuity, by ensuring all relevant points are included.