ModuleCohomology.lean
Nyll.ClassFieldTheory.LocalClassFieldTheory.Finite.Unramified.Cohomology
12 declarations indexed from sourceView source ↗ Module documentation
Tate cohomology of units in unramified extensions
For an unramified extension of local fields the actual low-degree Tate cohomology of the integer units and of every principal-unit group is trivial. The norm statements are the corresponding actual norm surjections.
Declarations
LocalClassFieldTheory.galoisGroupPrincipalUnitsMulDistribMulActionOfIsIntegralClosure
DocumentationThe actual integral-closure Galois action on U_L^n, packaged as the multiplicative action used by low-degree Tate cohomology.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.galoisGroupPrincipalUnitsMulDistribMulActionOfIsIntegralClosure_smul
DocumentationStates the theorem galoisGroupPrincipalUnitsMulDistribMulActionOfIsIntegralClosure_smul.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.principalUnitsIntegerUnitsInclusion
DocumentationInclusion in the actual short exact sequence 1 → U_L^n → 𝒪_Lˣ → 𝒪_Lˣ/U_L^n → 1.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.integerUnitsPrincipalUnitsQuotientMap
DocumentationQuotient map in the actual short exact sequence 1 → U_L^n → 𝒪_Lˣ → 𝒪_Lˣ/U_L^n → 1.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.principalUnitsIntegerUnits_shortExact
DocumentationThe standard principal-unit sequence is short exact and equivariant for the actual integral-closure Galois actions.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.exists_integerUnit_map_eq_of_galoisGroup_fixed
DocumentationA Galois-fixed actual integer unit descends to a base integer unit. This is valuation-ring descent, not an assumed comparison of fixed parts.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.integerUnits_herbrandQuotient_eq_one
DocumentationThe normal-basis construction, restricted to its actual integer-unit conclusion h(G,𝒪_Lˣ)=1.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.herbrandHMinusOne_subsingleton_of_h0_subsingleton_of_quotient_eq_one
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.unramified_integerUnits_herbrand_subsingleton
DocumentationThe unramified unit-cohomology theorem for the actual integer-unit module: both low-degree Tate groups are trivial in an unramified extension.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.unramified_principalUnits_herbrand_subsingleton
DocumentationThe unramified unit-cohomology theorem for the actual n-th principal-unit module. The proof uses the actual sequence 1 → U_L^n → 𝒪_Lˣ → 𝒪_Lˣ/U_L^n → 1, Herbrand-quotient multiplicativity, and the actual unramified norm lifting.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.unramified_units_tateCohomology_and_norm_surjective_for_generator
DocumentationGenerator-explicit form of the unramified unit-cohomology theorem. The canonical endpoint below supplies the canonical unramified arithmetic Frobenius.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand
LocalClassFieldTheory.unramified_units_tateCohomology_and_norm_surjective
DocumentationThe unramified unit-cohomology theorem. The arithmetic Frobenius and its generation property are constructed from unramifiedness, so the canonical endpoint has no extra chosen-generator argument.
Source context 8 commands
Surrounding namespaces, section variables, and local commands at this declaration.
noncomputable section
universe u
namespace LocalClassFieldTheory
open scoped ValuativeRel
open LocalFieldTheory
open LocalFieldTheory.IsNonarchimedeanLocalField
open CyclicCohomology
open CyclicCohomology.ProfiniteCohomology.Herbrand