Foundation of modern set theory.

Formal foundation for mathematics using sets.

In mathematical logic, descriptive set theory is the study of certain classes of "well-behaved" subsets of the real line and other Polish spaces.

any of several theories of sets used in the discussion of the foundations of mathematics.

(mathematics) An axiomatic system that was proposed in the early 20th century in order to formulate a theory of sets free from paradoxes such as Russell's paradox, and became the standard form of axiomatic set theory.

Axiomatic constructive set theory is an approach to mathematical constructivism following the program of axiomatic set theory.

Cantor's first set theory article contains Georg Cantor's first theorems of transfinite set theory, which studies infinite sets and their properties.