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  2. Descriptive set theory - Wikipedia

    en.wikipedia.org/wiki/Descriptive_set_theory

    In mathematical logic, descriptive set theory (DST) is the study of certain classes of "well-behaved" subsets of the real line and other Polish spaces.As well as being one of the primary areas of research in set theory, it has applications to other areas of mathematics such as functional analysis, ergodic theory, the study of operator algebras and group actions, and mathematical logic.

  3. Set theory - Wikipedia

    en.wikipedia.org/wiki/Set_theory

    e. Set theory is the branch of mathematical logic that studies sets, which can be informally described as collections of objects. Although objects of any kind can be collected into a set, set theory — as a branch of mathematics — is mostly concerned with those that are relevant to mathematics as a whole. The modern study of set theory was ...

  4. Zermelo–Fraenkel set theory - Wikipedia

    en.wikipedia.org/wiki/Zermelo–Fraenkel_set_theory

    Zermelo–Fraenkel set theory. In set theory, Zermelo–Fraenkel set theory, named after mathematicians Ernst Zermelo and Abraham Fraenkel, is an axiomatic system that was proposed in the early twentieth century in order to formulate a theory of sets free of paradoxes such as Russell's paradox. Today, Zermelo–Fraenkel set theory, with the ...

  5. Large cardinal - Wikipedia

    en.wikipedia.org/wiki/Large_cardinal

    Large cardinal. In the mathematical field of set theory, a large cardinal property is a certain kind of property of transfinite cardinal numbers. Cardinals with such properties are, as the name suggests, generally very "large" (for example, bigger than the least α such that α=ω α). The proposition that such cardinals exist cannot be proved ...

  6. Tarski–Grothendieck set theory - Wikipedia

    en.wikipedia.org/wiki/Tarski–Grothendieck_set...

    Tarski–Grothendieck set theory (TG, named after mathematicians Alfred Tarski and Alexander Grothendieck) is an axiomatic set theory.It is a non-conservative extension of Zermelo–Fraenkel set theory (ZFC) and is distinguished from other axiomatic set theories by the inclusion of Tarski's axiom, which states that for each set there is a Grothendieck universe it belongs to (see below).

  7. Grothendieck universe - Wikipedia

    en.wikipedia.org/wiki/Grothendieck_universe

    is an element of U. A Grothendieck universe is meant to provide a set in which all of mathematics can be performed. (In fact, uncountable Grothendieck universes provide models of set theory with the natural ∈-relation, natural powerset operation etc.). Elements of a Grothendieck universe are sometimes called small sets.

  8. Set-builder notation - Wikipedia

    en.wikipedia.org/wiki/Set-builder_notation

    Set-builder notation can be used to describe a set that is defined by a predicate, that is, a logical formula that evaluates to true for an element of the set, and false otherwise. [3] In this form, set-builder notation has three parts: a variable, a colon or vertical bar separator, and a predicate. Thus there is a variable on the left of the ...

  9. Von Neumann–Bernays–Gödel set theory - Wikipedia

    en.wikipedia.org/wiki/Von_Neumann–Bernays...

    Von Neumann–Bernays–Gödel set theory. In the foundations of mathematics, von Neumann–Bernays–Gödel set theory (NBG) is an axiomatic set theory that is a conservative extension of Zermelo–Fraenkel–choice set theory (ZFC). NBG introduces the notion of class, which is a collection of sets defined by a formula whose quantifiers range ...