Module

SmallBigHilbertClassFieldIffOfNoReal.lean

Nyll.ClassFieldTheory.Theorems.FrobeniusAndHilbertClassFields.SmallBigHilbertClassFieldIffOfNoReal
1 declaration indexed from sourceView source ↗

Hilbert class fields without real places

When the base has no real places, no extension can ramify at an infinite place. Thus the small and big Hilbert class field conditions agree.

Declarations

ClassFieldTheory.isSmallHilbertClassField_iff_isBig_of_noReal

Over a number field without real places, the small and big Hilbert class field predicates on a fixed finite abelian extension coincide.

Source context 2 commands

Surrounding namespaces, section variables, and local commands at this declaration.

namespace ClassFieldTheory
universe u
theorem isSmallHilbertClassField_iff_isBig_of_noReal
    (K : Type u) [Field K] [NumberField K]
    [IsEmpty (RayClassRealPlace K)]
    (E : FiniteAbelianExtension K) :
    IsSmallHilbertClassField E ↔ IsBigHilbertClassField E