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Project-declaredLean 4.32.0 · mathlib@249c48c2

Quotient Group is Unimodular Group

QuotientGroup.isUnimodularGroup

Plain-language statement

The quotient of a Hausdorff second countable unimodular group by a central normal closed subgroup is still unimodular.

Exact Lean statement

lemma _root_.QuotientGroup.isUnimodularGroup
    {G : Type*} [Group G] [TopologicalSpace G] [IsUnimodularGroup G]
    [T2Space G] [SecondCountableTopology G] (N : Subgroup G) [N.Normal]
    (hN : N ≤ .center G) (hN' : IsClosed (X := G) N) : IsUnimodularGroup (G ⧸ N) where
  modularCharacter_eq_one

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
lemma _root_.QuotientGroup.isUnimodularGroup    {G : Type*} [Group G] [TopologicalSpace G] [IsUnimodularGroup G]    [T2Space G] [SecondCountableTopology G] (N : Subgroup G) [N.Normal]    (hN : N  .center G) (hN' : IsClosed (X := G) N) : IsUnimodularGroup (G ⧸ N) where  modularCharacter_eq_one := by    ext g    borelize G    have H : MulDistribMulAction.toContinuousMulEquiv (ConjAct.toConjAct g) N = .refl _ := by      ext x      simp [-SetLike.coe_eq_coe, ConjAct.Subgroup.val_conj_smul, ConjAct.toConjAct_smul,         ((hN x.prop).comm g).eq]    have := modularCharacter_eq_modularCharacter_quotient_mul_mulEquivHaarChar N g    simpa [IsUnimodularGroup.modularCharacter_eq_one, H] using this.symm
Project
Fermat's Last Theorem
License
Apache-2.0
Commit
8dd808888295
Source
FLT/HaarMeasure/Quotient.lean:383-395

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Related declarations

Project-declaredLean 4.32.0

Eq finsum quotient out of bij On

AbstractHeckeOperator.eq_finsum_quotient_out_of_bijOn'

Plain-language statement

If a is fixed by V then ∑ᶠ g ∈ s, g • a is independent of the choice s of coset representatives in G for a subset of G ⧸ V

number theoryarithmetic geometryFermat's Last Theorem

Source project: Fermat's Last Theorem

Person-level attribution pending.

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Project-declaredLean 4.32.0

Comm Group no compact automorphisms

CommGroup.no_compact_automorphisms

Plain-language statement

A connected compact Hausdorff abelian topological group does not admit a nontrivial compact group of automorphisms.

number theoryarithmetic geometryFermat's Last Theorem

Source project: Fermat's Last Theorem

Person-level attribution pending.

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