Georg Cantor is widely recognized as the founder of Set Theory due to his groundbreaking work on infinite sets and the concept of transfinite numbers.

Russell's Paradox, also known as the Russell-Zermelo Paradox, is a logical contradiction that arises when considering the set of all sets that do not contain themselves.

The Axiom of Choice is a controversial axiom in Set Theory that asserts the existence of a choice function for every collection of non-empty sets.

The Universal Set, also known as the Universe of Discourse, is the set that contains all elements under consideration in a given context.

Georg Cantor introduced the concept of ordinal numbers and developed the theory of well-ordering, which is fundamental to the study of infinite sets.

The Power Set of a set A, denoted by $\mathcal{P}(A)$, is the set of all subsets of A.

The Axiom of Extensionality is a fundamental axiom in Set Theory that defines the equality of sets based on their elements.

A Singleton Set is a set that contains exactly one element.

Ernst Zermelo developed the Zermelo-Fraenkel Set Theory, which is the most widely accepted axiomatic foundation of Set Theory.

The Empty Set, also known as the Null Set, is the set that contains no elements.

The Axiom of Power Set states that for any set A, the set of all subsets of A, denoted by $\mathcal{P}(A)$, is also a set.

The Real Number Set, denoted by $\mathbb{R}$, is the set of all real numbers.

Georg Cantor introduced the concept of transfinite numbers and developed the theory of cardinal and ordinal arithmetic, which extended the concept of numbers beyond the natural numbers.

Russell's Paradox, also known as the Russell-Zermelo Paradox, is a logical contradiction that arises when considering the set of all sets that contain themselves.

The Axiom of Union states that for any set A, there exists a set B such that every element of A is an element of B.