Kuratowski closure-complement theorem

The Kuratowski closure-complement theorem is a key result in topology, a branch of mathematics that studies spaces and their properties. It states that you can perform a sequence of “closure” and “complement” operations on a set in a space, and there are only 14 unique outcomes. This means, regardless of your starting set, if you keep applying these operations, you won't create new types of sets beyond these 14. It highlights how these operations interact and helps mathematicians understand the structure of topological spaces.