• 1 Introduction
  • 2 Group Cohomology ▶
    • 2.1 Introduction
    • 2.2 Group cohomology and homology
    • 2.3 Tate Cohomology
    • 2.4 Coinduction and induction
    • 2.5 Dimension-shifting ▶
      • 2.5.1 Shifting \(\mathrm{up}\)
      • 2.5.2 Shifting \(\mathrm{down}\)
    • 2.6 The inflation-restriction sequence
    • 2.7 Corestriction
    • 2.8 Periodicity for finite cyclic groups
    • 2.9 Herbrand quotients
    • 2.10 The Triviality Criterion
    • 2.11 The splitting module of a 2-cocycle
    • 2.12 The Reciprocity Isomorphism
    • 2.13 Compatibility in towers
  • 3 Local Class Field Theory ▶
    • 3.1 Notation and Preliminary results
    • 3.2 The Herbrand quotient of \(l^{\times }\)
    • 3.3 An upper bound for \(H^2(l/k,l^\times )\)
    • 3.4 Fundamental classes in unramified extensions
    • 3.5 Construction of fundamental classes
    • 3.6 Some consequences of the reciprocity isomorphism
  • 4 Global Class Field Theory ▶
    • 4.1 Choice of \(S\)
    • 4.2 The Herbrand quotient of the \(S\)-ideles
    • 4.3 The Herbrand quotient of the \(S\)-units
    • 4.4 Dirichlet Density
    • 4.5 Some \(L\)-functions
    • 4.6 The first inequality
  • 5 References
  • Dependency graph

Class Field Theory

Kevin Buzzard Richard Hill others

  • 1 Introduction
  • 2 Group Cohomology
    • 2.1 Introduction
    • 2.2 Group cohomology and homology
    • 2.3 Tate Cohomology
    • 2.4 Coinduction and induction
    • 2.5 Dimension-shifting
      • 2.5.1 Shifting \(\mathrm{up}\)
      • 2.5.2 Shifting \(\mathrm{down}\)
    • 2.6 The inflation-restriction sequence
    • 2.7 Corestriction
    • 2.8 Periodicity for finite cyclic groups
    • 2.9 Herbrand quotients
    • 2.10 The Triviality Criterion
    • 2.11 The splitting module of a 2-cocycle
    • 2.12 The Reciprocity Isomorphism
    • 2.13 Compatibility in towers
  • 3 Local Class Field Theory
    • 3.1 Notation and Preliminary results
    • 3.2 The Herbrand quotient of \(l^{\times }\)
    • 3.3 An upper bound for \(H^2(l/k,l^\times )\)
    • 3.4 Fundamental classes in unramified extensions
    • 3.5 Construction of fundamental classes
    • 3.6 Some consequences of the reciprocity isomorphism
  • 4 Global Class Field Theory
    • 4.1 Choice of \(S\)
    • 4.2 The Herbrand quotient of the \(S\)-ideles
    • 4.3 The Herbrand quotient of the \(S\)-units
    • 4.4 Dirichlet Density
    • 4.5 Some \(L\)-functions
    • 4.6 The first inequality
  • 5 References