Module

ConstantsAreBase_of_exists_isRational.lean

Nyll.AlgebraicCurves.FunctionFields.ConstantsAreBase_of_exists_isRational
4 declarations indexed from sourceView source ↗

ConstantsAreBase of exists isRational

A rational place of nonzero degree identifies the constant field with the base field, using the degree of principal divisors.

Declarations

AlgebraicCurve.Place.ord_sub_evalAt_pos_s17
Source context 11 commands

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

section ProofImplementation
namespace AlgebraicCurves.FunctionFields.Proofs.ConstantsAreBase_of_exists_isRational
open _root_.AlgebraicCurve
namespace AlgebraicCurve
open _root_.AlgebraicCurve
open _root_.AlgebraicCurve
namespace Place
open _root_.AlgebraicCurve.Place
open _root_.AlgebraicCurve.Place
variable {K F : Type*} [Field K] [Field F] [Algebra K F] (v : Place K F)
open IsLocalRing in
theorem _root_.AlgebraicCurve.Place.ord_sub_evalAt_pos_s17 (hrat : v.IsRational) {f : F}
  (hf : f ∈ v.toValuationSubring)
    (hne : f - algebraMap K F (v.evalAt f) ≠ 0) :
    0 < v.ord (f - algebraMap K F (v.evalAt f))
AlgebraicCurves.FunctionFields.Proofs.ConstantsAreBase_of_exists_isRational.AlgebraicCurve.Place.eq_algebraMap_of_forall_ord_nonneg_s17
Source context 12 commands

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

section ProofImplementation
namespace AlgebraicCurves.FunctionFields.Proofs.ConstantsAreBase_of_exists_isRational
open _root_.AlgebraicCurve
namespace AlgebraicCurve
open _root_.AlgebraicCurve
open _root_.AlgebraicCurve
namespace Place
open _root_.AlgebraicCurve.Place
open _root_.AlgebraicCurve.Place
variable {K F : Type*} [Field K] [Field F] [Algebra K F] (v : Place K F)
open _root_.AlgebraicCurve.Place
variable [HasPrincipalDivisors K F]
theorem eq_algebraMap_of_forall_ord_nonneg_s17 (v₀ : Place K F) (hrat : v₀.IsRational)
    (hdeg : v₀.deg ≠ 0) {g : F} (hg : g ≠ 0) (hord : ∀ v : Place K F, 0 ≤ v.ord g) :
    ∃ c : K, g = algebraMap K F c
AlgebraicCurves.FunctionFields.Proofs.ConstantsAreBase_of_exists_isRational.AlgebraicCurve.constantsAreBase_of_exists_isRational_s17
Source context 6 commands

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

section ProofImplementation
namespace AlgebraicCurves.FunctionFields.Proofs.ConstantsAreBase_of_exists_isRational
open _root_.AlgebraicCurve
namespace AlgebraicCurve
open _root_.AlgebraicCurve
open _root_.AlgebraicCurve
theorem constantsAreBase_of_exists_isRational_s17 {K F : Type*} [Field K] [Field F] [Algebra K F]
    [HasPrincipalDivisors K F]
    (v₀ : Place K F) (hrat : v₀.IsRational) (hdeg : v₀.deg ≠ 0) :
    ConstantsAreBase K F
AlgebraicCurve.constantsAreBase_of_exists_isRational
Source context 3 commands

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

section ProofImplementation
namespace AlgebraicCurves.FunctionFields.Proofs.ConstantsAreBase_of_exists_isRational
open _root_.AlgebraicCurve
theorem _root_.AlgebraicCurve.constantsAreBase_of_exists_isRational {K F : Type*} [Field K]
  [Field F] [Algebra K F]
    [AlgebraicCurve.HasPrincipalDivisors K F]
    (v₀ : AlgebraicCurve.Place K F) (hrat : v₀.IsRational) (hdeg : v₀.deg ≠ 0) :
    AlgebraicCurve.ConstantsAreBase K F