ModuleFixedFields.lean
Nyll.ValuedFieldTheory.Ramification.HilbertRamification.Dedekind.FixedFields
23 declarations indexed from sourceView source ↗ Module documentation
Hilbert ramification theory: decomposition and inertia fields
This file contains the fixed-field layer of prime-decomposition theory. The Dedekind-domain file defines the decomposition and inertia groups attached to a prime ideal; here we view those groups as subgroups of a finite Galois group acting on the fraction field and use mathlib's Galois correspondence.
Declarations
HilbertRamification.Dedekind.fixedFieldOfSubgroup
DocumentationThe fixed field of a subgroup of a finite Galois group, in the IsGaloisGroup formulation used by the Dedekind ramification API.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
HilbertRamification.Dedekind.mem_fixedFieldOfSubgroup_iff
DocumentationElementwise membership in the fixed field of a subgroup.
Source context 9 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
HilbertRamification.Dedekind.mem_fixedFieldOfSubgroup_iff_forall_mem
DocumentationMembership in a subgroup fixed field, written with subgroup membership rather than subtype elements.
Source context 9 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
HilbertRamification.Dedekind.fixedFieldOfSubgroup_fixingSubgroup_eq
DocumentationThe subgroup fixing the fixed field of a subgroup is the subgroup itself.
Source context 10 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
HilbertRamification.Dedekind.fixedFieldOfSubgroup_eq_top_iff_subgroup_eq_bot
DocumentationA subgroup has full fixed field exactly when it is trivial.
Source context 11 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.fixedFieldOfSubgroup_eq_bot_iff_subgroup_eq_top
DocumentationA subgroup has base fixed field exactly when it is all of the Galois group.
Source context 11 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.decompositionField
DocumentationThe decomposition and inertia definition: the decomposition field Z_P, as the fixed field of the decomposition group.
Source context 12 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.mem_decompositionField_iff
DocumentationElementwise membership in the decomposition field.
Source context 13 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindDecomposition_decompositionField_fixingSubgroup_eq
DocumentationDecomposition and inertia groups satisfy: the subgroup fixing the decomposition field is the decomposition group.
Source context 14 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.dedekindDecomposition_decompositionField_eq_top_iff_decompositionGroup_eq_bot
DocumentationDecomposition and inertia groups satisfy: G_P = 1 if and only if Z_P = L.
Source context 15 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindDecomposition_decompositionField_eq_bot_iff_decompositionGroup_eq_top
DocumentationDecomposition and inertia groups satisfy: G_P = G if and only if Z_P = K.
Source context 15 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindDecomposition_decompositionField_eq_top_iff_primesOver_ncard_eq_card
DocumentationDecomposition and inertia groups satisfy: the fixed-field form of total splitting, Z_P = L iff the number of primes above p is #G.
Source context 15 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindDecomposition_decompositionField_eq_bot_iff_primesOver_ncard_eq_one
DocumentationDecomposition and inertia groups satisfy: the fixed-field form of nonsplitting, Z_P = K iff P is the only prime above p.
Source context 15 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindTower_decompositionField_finrank_eq_decomposition_card
DocumentationThe prime-decomposition tower identity: [L : Z_P] = #G_P.
Source context 16 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.decompositionGroup_isGaloisGroup
DocumentationThe prime-decomposition tower identity: the decomposition group is the Galois group of L/Z_P.
Source context 16 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.inertiaField
DocumentationThe inertia-field definition: the inertia field T_P, as the fixed field of the inertia group.
Source context 16 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.mem_inertiaField_iff
DocumentationElementwise membership in the inertia field.
Source context 17 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.decompositionField_le_inertiaField
DocumentationPrime-decomposition statement: the decomposition field is contained in the inertia field.
Source context 18 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.dedekindRamification_inertiaField_fixingSubgroup_eq
DocumentationPrime-decomposition statement: the subgroup fixing the inertia field is the inertia group.
Source context 18 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.dedekindRamification_inertiaField_eq_top_iff_inertiaGroup_eq_bot
DocumentationA fixed-field special case: I_P = 1 if and only if T_P = L.
Source context 19 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindRamification_inertiaField_eq_bot_iff_inertiaGroup_eq_top
DocumentationFixed-field source for the opposite extreme of the inertia field: I_P = G if and only if T_P = K.
Source context 19 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
HilbertRamification.Dedekind.dedekindRamification_inertiaField_finrank_eq_inertia_card
DocumentationA prime-decomposition consequence: [L : T_P] = #I_P.
Source context 20 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
HilbertRamification.Dedekind.inertiaGroup_isGaloisGroup
DocumentationA prime-decomposition consequence: the inertia group is the Galois group of L/T_P.
Source context 20 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
namespace HilbertRamification
namespace Dedekind
open Algebra Module
variable {A B K L : Type*}
variable [CommRing A] [CommRing B] [Algebra A B]
variable [Field K] [Field L] [Algebra K L]
variable (G : Type*) [Group G] [MulSemiringAction G L] [SMulCommClass G K L]
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)
variable {G}
variable (G)