Ambiguity — Sir John Tenniel s illustration of the Caterpillar for Lewis Carroll s Alice s Adventures in Wonderland is noted for its ambiguous central figure, whose head can be viewed as being a human male s face with a pointed nose and pointy chin or being… … Wikipedia
Set (mathematics) — This article gives an introduction to what mathematicians call intuitive or naive set theory; for a more detailed account see Naive set theory. For a rigorous modern axiomatic treatment of sets, see Set theory. The intersection of two sets is… … Wikipedia
Set theory — This article is about the branch of mathematics. For musical set theory, see Set theory (music). A Venn diagram illustrating the intersection of two sets. Set theory is the branch of mathematics that studies sets, which are collections of objects … Wikipedia
Set phrase — A set phrase is an expression (i.e. term or phrase) whose parts are fixed (see examples below). It is often possible to express the idea conveyed by a set phrase with a different phrasing, but it is marked to do so. Two word set phrases arise… … Wikipedia
Countable set — Countable redirects here. For the linguistic concept, see Count noun. Not to be confused with (recursively) enumerable sets. In mathematics, a countable set is a set with the same cardinality (number of elements) as some subset of the set of… … Wikipedia
Empty set — ∅ redirects here. For similar looking symbols, see Ø (disambiguation). The empty set is the set containing no elements. In mathematics, and more specifically set theory, the empty set is the unique set having no elements; its size or cardinality… … Wikipedia
Class (set theory) — In set theory and its applications throughout mathematics, a class is a collection of sets (or sometimes other mathematical objects) which can be unambiguously defined by a property that all its members share. The precise definition of class… … Wikipedia
Uncountable set — Uncountable redirects here. For the linguistic concept, see Uncountable noun. In mathematics, an uncountable set is an infinite set that contains too many elements to be countable. The uncountability of a set is closely related to its cardinal… … Wikipedia
Recursively enumerable set — In computability theory, traditionally called recursion theory, a set S of natural numbers is called recursively enumerable, computably enumerable, semidecidable, provable or Turing recognizable if: There is an algorithm such that the set of… … Wikipedia
List of set theory topics — Logic portal Set theory portal … Wikipedia
Constructive set theory — is an approach to mathematical constructivism following the program of axiomatic set theory. That is, it uses the usual first order language of classical set theory, and although of course the logic is constructive, there is no explicit use of… … Wikipedia