Module

SmallHilbertPairingTransport.lean

Nyll.ClassFieldTheory.LocalClassFieldTheory.Kummer.SmallHilbertPairingTransport
12 declarations indexed from sourceView source ↗

Transport of Hilbert pairings across field equivalences

The Type 0 local construction can be applied to a small representative of a local field. This file transports its public power-class and Kummer-norm statements back across the field equivalence.

Declarations

ClassFieldTheory.powerClassGroupEquivOfRingEquiv

A field equivalence identifies the groups of n-th power classes.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
def powerClassGroupEquivOfRingEquiv
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+) :
    PowerClassGroup F n ≃* PowerClassGroup G n
ClassFieldTheory.rootsOfUnityEquivOfRingEquiv

A field equivalence identifies the n-th roots of unity.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
def rootsOfUnityEquivOfRingEquiv
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty) :
    rootsOfUnity (n : ℕ) F ≃* rootsOfUnity (n : ℕ) G
ClassFieldTheory.powerClassGroupEquivOfRingEquiv_powerClass

The image of a representative under the induced power-class equivalence.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem powerClassGroupEquivOfRingEquiv_powerClass
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+) (a : Fˣ) :
    powerClassGroupEquivOfRingEquiv e n (powerClass F n a) =
      powerClass G n (Units.mapEquiv e.toMulEquiv a)
ClassFieldTheory.powerClassGroupEquivOfRingEquiv_symm_powerClass

A representative pulled back from the target power-class group.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem powerClassGroupEquivOfRingEquiv_symm_powerClass
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+) (a : Gˣ) :
    (powerClassGroupEquivOfRingEquiv e n).symm (powerClass G n a) =
      powerClass F n ((Units.mapEquiv e.toMulEquiv).symm a)
ClassFieldTheory.isKummerNorm_iff_of_ringEquiv

Kummer-algebra norm membership is invariant under a field equivalence, even when the Kummer polynomial is reducible.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem isKummerNorm_iff_of_ringEquiv
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+) (a b : Fˣ) :
    IsKummerNorm F n a b ↔
      IsKummerNorm G n
        (Units.mapEquiv e.toMulEquiv a)
        (Units.mapEquiv e.toMulEquiv b)
ClassFieldTheory.hilbertPairingOfRingEquiv

Pull a pairing on power classes across an equivalence of base fields.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
def hilbertPairingOfRingEquiv
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n) : HilbertPairing G n
ClassFieldTheory.hilbertPairingOfRingEquiv_apply

Evaluation of a transported Hilbert pairing.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem hilbertPairingOfRingEquiv_apply
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n)
    (x y : PowerClassGroup G n) :
    hilbertPairingOfRingEquiv e n hmu B x y =
      rootsOfUnityEquivOfRingEquiv e n hmu
        (B ((powerClassGroupEquivOfRingEquiv e n).symm x)
          ((powerClassGroupEquivOfRingEquiv e n).symm y))
ClassFieldTheory.hilbertPairingOfRingEquiv_isSteinberg

The Steinberg relation is preserved by base-field equivalence.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem hilbertPairingOfRingEquiv_isSteinberg
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n) (hB : B.IsSteinberg) :
    (hilbertPairingOfRingEquiv e n hmu B).IsSteinberg
ClassFieldTheory.hilbertPairingOfRingEquiv_isSkewSymmetric

Skew-symmetry is preserved by base-field equivalence.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem hilbertPairingOfRingEquiv_isSkewSymmetric
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n) (hB : B.IsSkewSymmetric) :
    (hilbertPairingOfRingEquiv e n hmu B).IsSkewSymmetric
ClassFieldTheory.hilbertPairingOfRingEquiv_isNondegenerate

Nondegeneracy in both variables is preserved by field equivalence.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem hilbertPairingOfRingEquiv_isNondegenerate
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n) (hB : B.IsNondegenerate) :
    (hilbertPairingOfRingEquiv e n hmu B).IsNondegenerate
ClassFieldTheory.hilbertPairingOfRingEquiv_satisfiesNormResidueCriterion

The canonical Kummer norm-residue law is preserved by field equivalence.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem hilbertPairingOfRingEquiv_satisfiesNormResidueCriterion
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n) (hB : B.SatisfiesNormResidueCriterion) :
    (hilbertPairingOfRingEquiv e n hmu B).SatisfiesNormResidueCriterion
ClassFieldTheory.hilbertPairingOfRingEquiv_isLocalHilbertPairing

All public local-pairing properties are invariant under a field equivalence.

Source context 3 commands

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

noncomputable section
namespace ClassFieldTheory
universe u v
theorem hilbertPairingOfRingEquiv_isLocalHilbertPairing
    {F : Type u} {G : Type v} [Field F] [Field G]
    (e : F ≃+* G) (n : ℕ+)
    (hmu : (primitiveRoots (n : ℕ) F).Nonempty)
    (B : HilbertPairing F n)
    (hB : HilbertPairing.IsLocalHilbertPairing B) :
    HilbertPairing.IsLocalHilbertPairing
      (hilbertPairingOfRingEquiv e n hmu B)