👉 In mathematics, an exterior is a subset of a topological space that can be considered as a part or boundary of another set. An exterior is often used in geometry and topology to describe the shape or behavior of objects. The concept of "exterior" in this context refers to the idea that certain subsets of a topological space are not only contained within it, but also form a part (or boundary) of it. This means that if we consider a subset E of a topological space
