Veblen hierarchy

E255569

The Veblen hierarchy is a transfinite sequence of ordinal functions used in mathematical logic and set theory to systematically generate and classify very large countable ordinals.

All labels observed (3)

Label Occurrences
Veblen hierarchy canonical 4
Veblen function φ_α 1
Veblen functions 1

How this entity was disambiguated

Statements (43)

Predicate Object
instanceOf construction in proof theory ⓘ
hierarchy of ordinal functions ⓘ
mathematical concept ⓘ
ordinal notation system ⓘ
appearsIn ordinal analysis of formal theories ⓘ
research on large countable ordinals ⓘ
basedOn normal functions on ordinals ⓘ
ordinal arithmetic ⓘ
canReach Feferman–Schütte ordinal Γ₀ ⓘ
cardinality countable range at each finite stage ⓘ
codomain ordinal numbers ⓘ
constructionDetail φ_{α+1} enumerates common fixed points of φ_α ⓘ
φ_λ for limit λ is defined via simultaneous recursion over all φ_α with α<λ ⓘ
constructionMethod iterating fixed-point operations on normal ordinal functions ⓘ
defines Veblen functions ⓘ
linked to: Veblen hierarchy
domain ordinal numbers ⓘ
field mathematical logic ⓘ
proof theory ⓘ
set theory ⓘ
generalizes Cantor normal form ⓘ
iterated exponential functions on ordinals ⓘ
hasPart Veblen function φ_α ⓘ
linked to: Veblen hierarchy
infiniteSequence indexed by ordinal parameters ⓘ
introducedIn early 20th century ⓘ
lowestLevel φ_0(β) = ω^β ⓘ
namedAfter Oswald Veblen ⓘ
notation φ_α(β) ⓘ
property each Veblen function is a normal function ⓘ
functions are strictly increasing and continuous in the ordinal topology ⓘ
purpose to classify large countable ordinals ⓘ
to generate large countable ordinals ⓘ
relatedTo Bachmann–Howard ordinal ⓘ
Feferman–Schütte ordinal Γ₀ ⓘ
epsilon numbers ⓘ
ordinal collapsing functions ⓘ
topic fixed points of normal functions ⓘ
large countable ordinals ⓘ
transfinite induction ⓘ
usedFor analyzing proof-theoretic ordinals ⓘ
describing fixed points of ordinal functions ⓘ
ordinal notation beyond ε₀ ⓘ
usedIn classification of proof-theoretic strength of theories ⓘ
uses transfinite recursion ⓘ

How these facts were elicited

Referenced by (6)

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

Oswald Veblen → notableWork → Veblen hierarchy ⓘ
Veblen hierarchy → defines → Veblen functions ⓘ
linked to: Veblen hierarchy
Veblen hierarchy → hasPart → Veblen function φ_α ⓘ
linked to: Veblen hierarchy
Feferman–Schütte ordinal → definedUsing → Veblen hierarchy ⓘ
Cantor normal form → relatedConcept → Veblen hierarchy ⓘ
Bachmann–Howard ordinal → relatedTo → Veblen hierarchy ⓘ