Module

RingHilbertRamificationComparison.lean

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

The ring-character wild predicate is actual Hilbert ramification

This consumer uses the native decomposition action on the actual valuation subring. Both individual ring maps in the sparse comparison are supplied by that action; their coefficient compatibility is definitional.

Declarations

RamificationTheory.HilbertRamification.ValuationSubring.mem_ramificationGroup_iff_principalUnitMultipliers

Actual Hilbert ramification is exactly the principal-unit multiplier predicate used by the ring-only DVR character kernel.

Source context 3 commands

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

noncomputable section
namespace RamificationTheory.HilbertRamification.ValuationSubring
universe u v
theorem mem_ramificationGroup_iff_principalUnitMultipliers
    (K : Type u) {L : Type v} [Field K] [Field L] [Algebra K L]
    (V : _root_.ValuationSubring L) (σ : inertiaGroup K V) :
    σ ∈ ramificationGroup K V ↔
      ∀ x : V, ∃ a : Vˣ,
        (σ : decompositionGroup K V) • x = x * (a : V) ∧
          (a : V) - 1 ∈ IsLocalRing.maximalIdeal V