Hasse–Arf theorem

E207315

The Hasse–Arf theorem is a fundamental result in algebraic number theory that precisely characterizes the jumps in the ramification filtration of abelian extensions of local fields, showing they occur at integer values.

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Statements (43)

Predicate Object
instanceOf mathematical theorem ⓘ
result in local class field theory ⓘ
theorem in algebraic number theory ⓘ
appliesTo Galois groups of abelian extensions of local fields ⓘ
finite abelian extensions of local fields ⓘ
asserts jumps in the upper numbering ramification filtration of abelian extensions occur at integers ⓘ
clarifies structure of higher ramification groups in abelian extensions ⓘ
concerns abelian extensions of local fields ⓘ
jumps in the ramification filtration ⓘ
ramification filtration ⓘ
upper numbering ramification groups ⓘ
context Galois theory of local fields ⓘ
local class field theory ⓘ
valuation theory ⓘ
contrastsWith non-abelian extensions where upper ramification breaks may be non-integral ⓘ
field algebraic number theory ⓘ
local field theory ⓘ
ramification theory ⓘ
holdsFor finite abelian Galois extensions of non-archimedean local fields ⓘ
implies Artin conductors of characters of abelian local Galois groups are integers ⓘ
Swan conductors of characters of abelian local Galois groups are integers ⓘ
breaks in the upper ramification filtration of abelian extensions are integers ⓘ
ramification breaks of abelian extensions in upper numbering are not fractional ⓘ
involves Galois group filtration by higher ramification groups ⓘ
complete discretely valued fields with finite residue field ⓘ
discrete valuation fields ⓘ
namedAfter Cahit Arf ⓘ
Helmut Hasse ⓘ
relatedTo Artin conductor ⓘ
Herbrand function ⓘ
Swan conductor ⓘ
ramification breaks ⓘ
relates upper numbering and lower numbering of ramification groups ⓘ
status classical theorem in local field theory ⓘ
fundamental result in algebraic number theory ⓘ
typeOf integrality theorem in ramification theory ⓘ
usedIn analysis of wild ramification ⓘ
computation of discriminants of abelian extensions ⓘ
local class field theory reciprocity ⓘ
study of conductors of Galois representations ⓘ
study of local L-factors ⓘ
uses lower numbering of ramification groups ⓘ
upper numbering of ramification groups ⓘ

How these facts were elicited

Referenced by (5)

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

Helmut Hasse → notableWork → Hasse–Arf theorem ⓘ
Cahit Arf → knownFor → Hasse–Arf theorem ⓘ
Cahit Arf → notableConcept → Hasse–Arf theorem ⓘ
Cahit Arf → notableFor → Hasse–Arf theorem ⓘ
subject linked to: Arf
local class field theory → hasTheorem → Hasse–Arf theorem (in the abelian case) ⓘ
linked to: Hasse–Arf theorem