Module

FrattiniQuotient.lean

Nyll.ProCGroups.ProP.FrattiniQuotient
8 declarations indexed from sourceView source ↗

The power--commutator quotient

This file exposes the quotient by the closed subgroup generated by pth powers and commutators. The quotient is commutative and has exponent dividing p. These facts are the algebraic input for the pro-p Frattini quotient; no equality with the Frattini subgroup is assumed.

Declarations

Source context 4 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
instance : (closedPowerCommutator p G).Normal
ClassFieldTower.ProP.powerCommutatorQuotient

The quotient by the closed subgroup generated by pth powers and commutators.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
abbrev powerCommutatorQuotient
ClassFieldTower.ProP.powerCommutatorQuotientMk

The continuous quotient map to the power--commutator quotient.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
def powerCommutatorQuotientMk :
    G →ₜ* powerCommutatorQuotient p G
ClassFieldTower.ProP.powerCommutatorQuotientMk_surjective

The canonical map to the power--commutator quotient is surjective.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem powerCommutatorQuotientMk_surjective :
    Function.Surjective (powerCommutatorQuotientMk p G)
ClassFieldTower.ProP.ker_powerCommutatorQuotientMk

The kernel of the quotient map is the closed power--commutator subgroup.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem ker_powerCommutatorQuotientMk :
    (powerCommutatorQuotientMk p G).ker = closedPowerCommutator p G
ClassFieldTower.ProP.powerCommutatorQuotient_isMulCommutative

The power--commutator quotient is commutative.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem powerCommutatorQuotient_isMulCommutative :
    IsMulCommutative (powerCommutatorQuotient p G)
ClassFieldTower.ProP.powerCommutatorQuotient_pow_eq_one

Every element of the power--commutator quotient has pth power one.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem powerCommutatorQuotient_pow_eq_one
    (x : powerCommutatorQuotient p G) : x ^ p = 1
ClassFieldTower.ProP.powerCommutatorQuotient_mul_comm

Multiplication in the power--commutator quotient is commutative.

Source context 5 commands

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

namespace ClassFieldTower.ProP
universe u
section
variable (p : ℕ) (G : Type u) [TopologicalSpace G] [Group G] [IsTopologicalGroup G]

/- A single canonical local normality route supplies every quotient operation
in this file without exporting a competing global instance. -/
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem powerCommutatorQuotient_mul_comm
    (x y : powerCommutatorQuotient p G) : x * y = y * x