Module

FiniteInertiaDetection.lean

Nyll.ValuedFieldTheory.Ramification.HilbertRamification.FiniteInertiaDetection
1 declaration indexed from sourceView source ↗

Prime-order inertia detects residual roots

The faithful residue-unit character in characteristic zero turns a nonidentity prime-order inertia element into an actual primitive root in the residue field.

Declarations

RamificationTheory.HilbertRamification.ValuationSubring.exists_primitiveRoot_residue_of_inertia_prime_order

In residue characteristic zero, a nontrivial inertia element of prime order forces a primitive root of that order in the actual residue field.

Source context 3 commands

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

namespace RamificationTheory.HilbertRamification.ValuationSubring
universe u v
variable (K : Type u) {L : Type v} [Field K] [Field L] [Algebra K L]
theorem exists_primitiveRoot_residue_of_inertia_prime_order
    (A : _root_.ValuationSubring L) [Finite (inertiaGroup K A)]
    [CharZero (IsLocalRing.ResidueField A)]
    {p : ℕ} (hp : p.Prime) (σ : inertiaGroup K A)
    (hσ : σ ≠ 1) (hpow : σ ^ p = 1) :
    (primitiveRoots p (IsLocalRing.ResidueField A)).Nonempty