Module

QuotientTransport.lean

Nyll.ClassFieldTheory.GlobalClassFieldTheory.GlobalClassFields.ClosedFiniteIndexClassFieldReciprocity.Topological.QuotientTransport
2 declarations indexed from sourceView source ↗

Continuous transport between equal quotient groups

Equality of normal subgroups identifies their quotient groups with the same native quotient topology. Eliminating the equality therefore gives the continuous multiplicative equivalence directly; no discrete-topology instances or domain-specific class-field tower are required.

Declarations

QuotientGroup.quotientContinuousMulEquivOfEq

Equal normal subgroups induce a continuous multiplicative equivalence between their quotient groups with their native quotient topologies.

Source context 3 commands

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

noncomputable section
namespace QuotientGroup
variable {G : Type*} [Group G] [TopologicalSpace G]
def quotientContinuousMulEquivOfEq
    {N H : Subgroup G} [N.Normal] [H.Normal]
    (h : N = H) :
    G ⧸ N ≃ₜ* G ⧸ H
QuotientGroup.quotientContinuousMulEquivOfEq_apply

Forgetting topology from quotientContinuousMulEquivOfEq recovers the canonical multiplicative equivalence induced by the same equality.

Source context 3 commands

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

noncomputable section
namespace QuotientGroup
variable {G : Type*} [Group G] [TopologicalSpace G]
theorem quotientContinuousMulEquivOfEq_apply
    {N H : Subgroup G} [N.Normal] [H.Normal]
    (h : N = H) (x : G ⧸ N) :
    quotientContinuousMulEquivOfEq h x =
      QuotientGroup.quotientMulEquivOfEq h x