List of set theory topics

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Set theory is the study of sets, which are groups of objects. This article introduces common topics in set theory, from basic ideas to advanced concepts. Key topics include basic operations on sets (union, intersection, difference), subsets, and how to count elements (cardinality). It also explores infinity and different sizes of infinity. The standard foundation is a system of rules called ZFC. Other important ideas are ordinals and cardinals (special numbers that describe size), functions, and relations. More advanced areas look at logic, topology, and descriptive set theory, along with famous questions about proofs, paradoxes, and how set theory helps build other areas of mathematics.