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Project-declaredLean 4.32.0 · mathlib@249c48c2

Valued adic Completion Semialg Hom

IsDedekindDomain.HeightOneSpectrum.Extension.valued_adicCompletionSemialgHom

Plain-language statement

The local ramification index for the extension L_w/K_v is equal to the global ramification index for the extension w/v. In other words, if x in K_v and i:K_v->L_w then w(i(x))=v(x)^e where e is computed globally.

Exact Lean statement

lemma valued_adicCompletionSemialgHom (x) :
    Valued.v (adicCompletionSemialgHom K L w x) = Valued.v x ^
      (w.1.under A).asIdeal.ramificationIdx' w.1.asIdeal

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
lemma valued_adicCompletionSemialgHom (x) :    Valued.v (adicCompletionSemialgHom K L w x) = Valued.v x ^      (w.1.under A).asIdeal.ramificationIdx' w.1.asIdeal := by  revert x  apply funext_iff.mp  symm  apply (adicCompletion.ofCompletion_surjective K v).injective_comp_right  apply UniformSpace.Completion.ext  · exact ((Valued.continuous_valuation_of_surjective      (v.valuedAdicCompletion_surjective K)).pow _).comp      (adicCompletion.continuous_ofCompletion K v)  · exact ((Valued.continuous_valuation_of_surjective (w.1.valuedAdicCompletion_surjective L)).comp      (adicCompletionSemialgHom_continuous K L w)).comp      (adicCompletion.continuous_ofCompletion K v)  intro a  simp only [Function.comp_apply, adicCompletion.valued_ofCompletion,    Valued.valuedCompletion_apply, w.2, adicCompletionSemialgHom_coe,    WithVal.equiv_symm_apply, WithVal.valued_toVal,  valuation_comap A K L B w.1 _]  rw [WithVal.valued_toVal]
Project
Fermat's Last Theorem
License
Apache-2.0
Commit
8dd808888295
Source
FLT/DedekindDomain/Completion/BaseChange.lean:206-224

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Plain-language statement

If a is fixed by V then ∑ᶠ g ∈ s, g • a is independent of the choice s of coset representatives in G for a subset of G ⧸ V

number theoryarithmetic geometryFermat's Last Theorem

Source project: Fermat's Last Theorem

Person-level attribution pending.

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Project-declaredLean 4.32.0

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Plain-language statement

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Person-level attribution pending.

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