Continuous (star-)algebra equivalences between continuous endomorphisms are (isometrically) inner #
This file shows that continuous (star-)algebra equivalences between continuous endomorphisms are
(isometrically) inner.
See Mathlib/LinearAlgebra/GeneralLinearGroup/AlgEquiv.lean for the non-continuous version.
The proof follows the same idea as the non-continuous version.
TODO: #
- when
V = W, we can state that the group homomorphism(V โL[๐] V)หฃ โ* ((V โL[๐] V) โA[๐] (V โL[๐] V))is surjective, seeModule.End.mulSemiringActionToAlgEquiv_conjAct_surjectivefor the non-continuous version of this.
theorem
ContinuousAlgEquiv.eq_continuousLinearEquivConjContinuousAlgEquiv
{๐ : Type u_1}
{V : Type u_2}
{W : Type u_3}
[NontriviallyNormedField ๐]
[SeminormedAddCommGroup V]
[SeminormedAddCommGroup W]
[NormedSpace ๐ V]
[NormedSpace ๐ W]
[SeparatingDual ๐ V]
[SeparatingDual ๐ W]
(f : (V โL[๐] V) โA[๐] W โL[๐] W)
:
โ (U : V โL[๐] W), f = U.conjContinuousAlgEquiv
This is the continuous version of AlgEquiv.eq_linearEquivConjAlgEquiv.
theorem
StarAlgEquiv.eq_linearIsometryEquivConjStarAlgEquiv
{๐ : Type u_1}
{V : Type u_2}
{W : Type u_3}
[RCLike ๐]
[NormedAddCommGroup V]
[InnerProductSpace ๐ V]
[CompleteSpace V]
[NormedAddCommGroup W]
[InnerProductSpace ๐ W]
[CompleteSpace W]
(f : (V โL[๐] V) โโโ[๐] W โL[๐] W)
(hf : Continuous โf)
:
โ (U : V โโแตข[๐] W), f = U.conjStarAlgEquiv
The โ-algebra equivalence version of
ContinuousAlgEquiv.eq_continuousLinearEquivConjContinuousAlgEquiv.
TODO: remove the hypothesis Continuous f, as star-algebra equivalences between endomorphisms are
automatically continuous.
@[instance 100]
instance
instOrderIsoClassContinuousLinearMapIdOfNonUnitalAlgEquivClassOfStarHomClassOfContinuousMapClass
{๐ : Type u_1}
{V : Type u_2}
{W : Type u_3}
[RCLike ๐]
[NormedAddCommGroup V]
[InnerProductSpace ๐ V]
[CompleteSpace V]
[NormedAddCommGroup W]
[InnerProductSpace ๐ W]
[CompleteSpace W]
{F : Type u_4}
[EquivLike F (V โL[๐] V) (W โL[๐] W)]
[NonUnitalAlgEquivClass F ๐ (V โL[๐] V) (W โL[๐] W)]
[StarHomClass F (V โL[๐] V) (W โL[๐] W)]
[ContinuousMapClass F (V โL[๐] V) (W โL[๐] W)]
:
OrderIsoClass F (V โL[๐] V) (W โL[๐] W)