import Definitions.Def_FLTPrelim_Ramification set_option autoImplicit false namespace GlobalGaloisRep variable {K L : Type*} [Field K] [Field L] [Algebra K L] def IsUnramifiedAt {G : Type*} [Monoid G] (ρ : (L ≃ₐ[K] L) →* G) (q : ℕ) : Prop := ∀ A : ValuationSubring L, A.LiesOverPrime q → A.inertiaSubgroupIn K ≤ ρ.ker lemma isUnramifiedAt_iff {G : Type*} [Monoid G] {ρ : (L ≃ₐ[K] L) →* G} {q : ℕ} : IsUnramifiedAt ρ q ↔ ∀ A : ValuationSubring L, A.LiesOverPrime q → ∀ σ : L ≃ₐ[K] L, σ ∈ A.inertiaSubgroupIn K → ρ σ = 1 := Iff.rfl end GlobalGaloisRep