List Of Large Cardinal Properties
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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 Î ...
properties. It is arranged roughly in order of the consistency strength of the axiom asserting the existence of cardinals with the given property. Existence of a
cardinal number In mathematics, cardinal numbers, or cardinals for short, are a generalization of the natural numbers used to measure the cardinality (size) of sets. The cardinality of a finite set is a natural number: the number of elements in the set. Th ...
κ of a given type implies the existence of cardinals of most of the types listed above that type, and for most listed cardinal descriptions φ of lesser consistency strength, ''V''κ satisfies "there is an unbounded class of cardinals satisfying φ". The following table usually arranges cardinals in order of
consistency strength In mathematical logic, two theories are equiconsistent if the consistency of one theory implies the consistency of the other theory, and vice versa. In this case, they are, roughly speaking, "as consistent as each other". In general, it is not p ...
, with size of the cardinal used as a tiebreaker. In a few cases (such as strongly compact cardinals) the exact consistency strength is not known and the table uses the current best guess. * "Small" cardinals: 0, 1, 2, ..., \aleph_0, \aleph_1,..., \kappa = \aleph_, ... (see
Aleph number In mathematics, particularly in set theory, the aleph numbers are a sequence of numbers used to represent the cardinality (or size) of infinite sets that can be well-ordered. They were introduced by the mathematician Georg Cantor and are named a ...
) *
worldly cardinal In mathematical set theory, a worldly cardinal is a cardinal κ such that the rank ''V''κ is a model of Zermelo–Fraenkel set theory. Relationship to inaccessible cardinals By Zermelo's theorem on inaccessible cardinals, every inaccessible cardi ...
s * weakly and strongly inaccessible, α-inaccessible, and hyper inaccessible cardinals * weakly and strongly Mahlo, α- Mahlo, and hyper Mahlo cardinals. * reflecting cardinals * weakly compact (= Π-indescribable), Π-indescribable, totally indescribable cardinals * λ-unfoldable, unfoldable cardinals, ν-indescribable cardinals and λ-shrewd, shrewd cardinals (not clear how these relate to each other). * ethereal cardinals, subtle cardinals * almost ineffable,
ineffable Ineffability is the quality of something that surpasses the capacity of language to express it, often being in the form of a taboo or incomprehensible term. This property is commonly associated with philosophy, aspects of existence, and similar ...
, ''n''-ineffable, totally ineffable cardinals * remarkable cardinals * α-Erdős cardinals (for
countable In mathematics, a set is countable if either it is finite or it can be made in one to one correspondence with the set of natural numbers. Equivalently, a set is ''countable'' if there exists an injective function from it into the natural numbers ...
α), 0# (not a cardinal), γ-iterable, γ-Erdős cardinals (for
uncountable In mathematics, an uncountable set (or uncountably infinite set) is an infinite set that contains too many elements to be countable. The uncountability of a set is closely related to its cardinal number: a set is uncountable if its cardinal num ...
γ) * almost Ramsey, Jónsson, Rowbottom,
Ramsey Ramsey may refer to: Geography British Isles * Ramsey, Cambridgeshire, a small market town in England * Ramsey, Essex, a village near Harwich, England ** Ramsey and Parkeston, a civil parish formerly called just "Ramsey" * Ramsey, Isle of Man, t ...
, ineffably Ramsey, completely Ramsey, strongly Ramsey, super Ramsey cardinals *
measurable cardinal In mathematics, a measurable cardinal is a certain kind of large cardinal number. In order to define the concept, one introduces a two-valued measure on a cardinal , or more generally on any set. For a cardinal , it can be described as a subdivisio ...
s, 0† * λ-strong, strong cardinals, tall cardinals * Woodin, weakly hyper-Woodin,
Shelah Shelah may refer to: * Shelah (son of Judah), a son of Judah according to the Bible * Shelah (name), a Hebrew personal name * Shlach, the 37th weekly Torah portion (parshah) in the annual Jewish cycle of Torah reading * Salih, a prophet described ...
, hyper-Woodin cardinals * superstrong cardinals (=1-superstrong; for ''n''-superstrong for ''n''≥2 see further down.) *
subcompact Subcompact car is a North American classification for cars smaller than a compact car. It is broadly equivalent to the B-segment (Europe), supermini (Great Britain) or A0-class (China) classifications. According to the U.S. Environmental Prot ...
, strongly compact (Woodin< strongly compact≤supercompact), supercompact, hypercompact cardinals * η-extendible, extendible cardinals * VopÄ›nka cardinals, Shelah for supercompactness, high jump cardinals * ''n''- superstrong (''n''≥2), ''n''- almost huge, ''n''- super almost huge, ''n''-
huge Huge may refer to: * Huge cardinal, a number in mathematics * ''Huge'' (Caroline's Spine album), 1996 * ''Huge'' (Hugh Hopper and Kramer album), 1997 * ''Huge'' (TV series), a television series on ABC Family * Huge (digital agency) * ''Huge'' ...
, ''n''- superhuge cardinals (1-huge=huge, etc.) * Wholeness axiom,
rank-into-rank In set theory, a branch of mathematics, a rank-into-rank embedding is a large cardinal property defined by one of the following four axioms given in order of increasing consistency strength. (A set of rank < λ is one of the elements of the set V< ...
(Axioms I3, I2, I1, and I0) The following even stronger large cardinal properties are not consistent with the axiom of choice, but their existence has not yet been refuted in ZF alone (that is, without use of the
axiom of choice In mathematics, the axiom of choice, or AC, is an axiom of set theory equivalent to the statement that ''a Cartesian product of a collection of non-empty sets is non-empty''. Informally put, the axiom of choice says that given any collection ...
). *
Reinhardt cardinal In set theory, a branch of mathematics, a Reinhardt cardinal is a kind of large cardinal. Reinhardt cardinals are considered under ZF (Zermelo–Fraenkel set theory without the Axiom of Choice), because they are inconsistent with ZFC (ZF with the A ...
,
Berkeley cardinal In set theory, Berkeley cardinals are certain large cardinals suggested by Hugh Woodin in a seminar at the University of California, Berkeley in about 1992. A Berkeley cardinal is a cardinal ''κ'' in a model of Zermelo–Fraenkel set theory with t ...


References

* * * * {{Cite journal, last=Solovay, first=Robert M., first2=William N. , last2=Reinhardt, first3= Akihiro , last3=Kanamori, year=1978, title=Strong axioms of infinity and elementary embeddings, journal=Annals of Mathematical Logic, volume=13, issue=1, pages=73–116, authorlink=Robert M. Solovay, url=http://math.bu.edu/people/aki/d.pdf, doi=10.1016/0003-4843(78)90031-1, doi-access=free


External links


Cantor's attic
!-- old versio
Cantor's attic
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some diagrams of large cardinal properties
*
Large cardinals In the mathematical field of set theory, a large cardinal property is a certain kind of property of Transfinite number, transfinite cardinal numbers. Cardinals with such properties are, as the name suggests, generally very "large" (for example, big ...
cs:Velké kardinály