von Neumann universe

E14977

The von Neumann universe is a cumulative, well-founded hierarchy of sets used as a standard model of the set-theoretic universe in axiomatic set theory.

All labels observed (3)

How this entity was disambiguated

Statements (49)

Predicate Object
instanceOf class
cumulative hierarchy
proper class
set-theoretic universe
alsoKnownAs von Neumann universe
surface form: cumulative hierarchy of sets
builtByTransfiniteRecursionOn ordinals
choiceAxiomMayHoldIn von Neumann universe self-link
contains all sets (in ZF/ZFC) as elements of some level V_α
containsAsSubstructure cumulative hierarchy of hereditarily finite sets
cumulativeProperty for all α, V_α = ⋃_{β<α} V_β for limit α and P(V_{α−1}) for successors
definedIn axiomatic set theory
extensionalityAxiomHoldsIn von Neumann universe self-link
firstInfiniteLevel V_ω
foundationAxiomHoldsIn von Neumann universe self-link
hasProperty cumulative
rank-initial segment structure
transitive
well-founded
historicallyIntroducedBy John von Neumann in the 1920s
infinityAxiomHoldsIn von Neumann universe self-link
isTransitiveClass von Neumann universe self-link
isUnionOf V_α for all ordinals α
levelNotation V_0 = ∅
V_{α+1} = P(V_α)
V_λ = ⋃_{β<λ} V_β for limit ordinal λ
membershipRelationRestrictedTo V forms a well-founded relation
namedAfter John von Neumann
pairingAxiomHoldsIn von Neumann universe self-link
powerSetAxiomHoldsIn von Neumann universe self-link
rankFunctionCharacterization x ∈ V_α iff rank(x) < α
rankFunctionCodomain ordinals
rankFunctionDomain all sets
relatedConcept Grothendieck universe
constructible universe L
rank hierarchy
replacementAxiomHoldsIn von Neumann universe self-link
satisfies Zermelo–Fraenkel set theory
surface form: Zermelo–Fraenkel set theory (ZF) under suitable assumptions

Zermelo–Fraenkel set theory
surface form: Zermelo–Fraenkel set theory with Choice (ZFC) under suitable assumptions
separationSchemaHoldsIn von Neumann universe self-link
subsetRelation for each α, V_α ⊂ V
symbol V
unionAxiomHoldsIn von Neumann universe self-link
usedAs standard model of the set-theoretic universe
usedIn forcing arguments (as ambient universe)
inner model theory
relative consistency proofs
V_0Equals empty set
V_1Contains all subsets of the empty set
V_ωContains all hereditarily finite sets

How these facts were elicited

Referenced by (15)

Full triples — surface form annotated when it differs from this entity's canonical label.

John von Neumann notableConcept von Neumann universe
Zermelo–Fraenkel set theory associatedWith von Neumann universe
this entity surface form: von Neumann cumulative hierarchy
von Neumann universe alsoKnownAs von Neumann universe
this entity surface form: cumulative hierarchy of sets
von Neumann universe foundationAxiomHoldsIn von Neumann universe self-link
von Neumann universe extensionalityAxiomHoldsIn von Neumann universe self-link
von Neumann universe pairingAxiomHoldsIn von Neumann universe self-link
von Neumann universe unionAxiomHoldsIn von Neumann universe self-link
von Neumann universe powerSetAxiomHoldsIn von Neumann universe self-link
von Neumann universe infinityAxiomHoldsIn von Neumann universe self-link
von Neumann universe replacementAxiomHoldsIn von Neumann universe self-link
von Neumann universe separationSchemaHoldsIn von Neumann universe self-link
von Neumann universe choiceAxiomMayHoldIn von Neumann universe self-link
von Neumann universe isTransitiveClass von Neumann universe self-link
ZF hasCumulativeHierarchy von Neumann universe
constructible universe isSubsetOf von Neumann universe