Kronecker–Weber theorem

E100232

The Kronecker–Weber theorem is a fundamental result in algebraic number theory stating that every finite abelian extension of the rational numbers is contained in a cyclotomic field generated by roots of unity.

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All labels observed (2)

Statements (43)

Predicate Object
instanceOf theorem in algebraic number theory
appliesTo finite Galois extensions of Q with abelian Galois group
characterizes finite abelian extensions of Q as subfields of cyclotomic fields
maximal abelian extension of Q
concerns abelian Galois extensions
class field theory over Q
extensions of the rational number field Q
describes finite abelian extensions of the rational numbers
domain Galois extensions of Q
number fields
equivalentTo statement that every finite abelian extension of Q has conductor n for some n and is contained in Q(ζ_n)
excludes non-abelian extensions of Q
field algebraic number theory
generalizationOf properties of cyclotomic fields studied by Gauss
hasConsequence classification of finite abelian extensions of Q by conductors
description of abelian Galois groups of Q as quotients of (Z/nZ)^×
historicalPeriod 19th century mathematics
implies Q^ab = ⋃_n Q(ζ_n)
the maximal abelian extension of Q is the union of all cyclotomic fields
involves cyclotomic fields
roots of unity
isPartOf global class field theory
namedAfter Heinrich Martin Weber
Leopold Kronecker
originallyFormulatedFor abelian extensions of Q
provedBy Heinrich Martin Weber
Leopold Kronecker
relatedTo Hilbert’s twelfth problem
surface form: Artin reciprocity law

Dirichlet characters
Hilbert class field
Hilbert’s twelfth problem
surface form: Kronecker Jugendtraum

ray class fields over Q
standardReference Algebraic Number Theory textbooks
Cassels–Fröhlich: Algebraic Number Theory
Neukirch: Algebraic Number Theory
states every finite abelian extension of Q is contained in Q(ζ_n) for some n
every finite abelian extension of the rational numbers is contained in a cyclotomic field
usesConcept Galois group
abelian group
conductor of an abelian extension
cyclotomic polynomial
local fields at primes of Q
ramification in number fields

Referenced by (4)

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

Leopold Kronecker notableWork Kronecker–Weber theorem
cyclotomic fields relatedTo Kronecker–Weber theorem
subject surface form: cyclotomic field
cyclotomic fields usedInProofOf Kronecker–Weber theorem
subject surface form: cyclotomic field
Hilbert’s twelfth problem involves Kronecker–Weber theorem
this entity surface form: Kronecker–Weber theorem as a special case