Stationary set

In set theory, a **stationary set** is a concept related to the properties of infinite sets, particularly in the context of uncountable cardinals and the study of subsets of the following types: 1. **Stationary Set:** A subset \( S \) of a regular uncountable cardinal \( \kappa \) is called a stationary set if it intersects every closed and bounded subset of \( \kappa \).