Module

PowerCommutatorUniversal.lean

Nyll.ProCGroups.ProP.PowerCommutatorUniversal
4 declarations indexed from sourceView source ↗

Universal property of the power--commutator quotient

The quotient by the closed subgroup generated by pth powers and commutators is universal for continuous homomorphisms into commutative exponent-p topological groups with closed identity.

Declarations

Source context 7 commands

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

namespace ClassFieldTower.ProP
universe u v
section
variable {p : ℕ}
variable {G : Type u} {A : Type v}
variable [TopologicalSpace G] [Group G] [IsTopologicalGroup G]
variable [TopologicalSpace A] [CommGroup A] [T1Space A]
instance : (closedPowerCommutator p G).Normal
ClassFieldTower.ProP.powerCommutatorQuotientLift

Universal lift from the power--commutator quotient to a commutative exponent-p target.

Source context 8 commands

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

namespace ClassFieldTower.ProP
universe u v
section
variable {p : ℕ}
variable {G : Type u} {A : Type v}
variable [TopologicalSpace G] [Group G] [IsTopologicalGroup G]
variable [TopologicalSpace A] [CommGroup A] [T1Space A]
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
def powerCommutatorQuotientLift
    (f : G →ₜ* A) (hA : ∀ a : A, a ^ p = 1) :
    powerCommutatorQuotient p G →ₜ* A
ClassFieldTower.ProP.powerCommutatorQuotientLift_apply_mk
Source context 8 commands

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

namespace ClassFieldTower.ProP
universe u v
section
variable {p : ℕ}
variable {G : Type u} {A : Type v}
variable [TopologicalSpace G] [Group G] [IsTopologicalGroup G]
variable [TopologicalSpace A] [CommGroup A] [T1Space A]
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem powerCommutatorQuotientLift_apply_mk
    (f : G →ₜ* A) (hA : ∀ a : A, a ^ p = 1) (g : G) :
    powerCommutatorQuotientLift f hA (powerCommutatorQuotientMk p G g) = f g
ClassFieldTower.ProP.powerCommutatorQuotientLift_unique

The universal lift is the unique continuous homomorphism whose composite with the quotient map is the given homomorphism.

Source context 8 commands

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

namespace ClassFieldTower.ProP
universe u v
section
variable {p : ℕ}
variable {G : Type u} {A : Type v}
variable [TopologicalSpace G] [Group G] [IsTopologicalGroup G]
variable [TopologicalSpace A] [CommGroup A] [T1Space A]
local instance : (closedPowerCommutator p G).Normal :=
  closedPowerCommutator_normal p G
theorem powerCommutatorQuotientLift_unique
    (f : G →ₜ* A) (hA : ∀ a : A, a ^ p = 1)
    (φ : powerCommutatorQuotient p G →ₜ* A)
    (hφ : φ.comp (powerCommutatorQuotientMk p G) = f) :
    φ = powerCommutatorQuotientLift f hA