set theory
branch of mathematics that studies sets, which are collections of objects
categorical set theory
sets defined using mathematical category theory
alternative set theory
alternative to the standard Zermelo–Fraenkel set theory
axiomatic set theory
version of set theory in which axioms are taken as uninterpreted rather than as formalizations of pre-existing truths; defined using a formal logic
set-theoretic topology
subject of mathematics combining set theory and general topology
Ackermann set theory
axiomatic set theory proposed by Wilhelm Ackermann