Continuous linear equivalences #
Notation #
Continuous semilinear / linear / star-linear equivalences between topological modules are denoted
by M ≃SL[σ] M₂, M ≃L[R] M₂ and M ≃L⋆[R] M₂.
Main Definitions #
toHomeomorphis the homeomorphism induced by a continuous (semi)linear equivalence.symmis the inverse of a continuous linear equivalence as a continuous linear equivalence.equivOfInversecreates aContinuousLinearEquivfrom twoContinuousLinearMaps that are inverse of each other (as functions). See alsoequivOfInverse'when they're inverse to each other as continuous linear maps.ofUnitis theContinuousLinearEquivcorresponding to a unit in the ring of continuous endomorphisms. SeetoUnitfor the inverse direction.ofIsHomeomorph: a linear equivalence that is a homeomorphism is a continuous linear equivalence.
Main Results #
LinearEquiv.isHomeomorph_iff: A linear equivalence between topological modules is a homeomorphism if and only if it is continuous in both directions.
Continuous linear equivalences between modules. We only put the type classes that are necessary
for the definition, although in applications M and M₂ will be topological modules over the
topological semiring R.
- toFun : M → M₂
- invFun : M₂ → M
- left_inv : Function.LeftInverse (↑self).invFun (↑↑self).toFun
- right_inv : Function.RightInverse (↑self).invFun (↑↑self).toFun
- continuous_toFun : Continuous (↑↑self).toFun
Continuous linear equivalences between modules. We only put the type classes that are necessary for the definition, although in applications
MandM₂will be topological modules over the topological semiringR. - continuous_invFun : Continuous (↑self).invFun
Continuous linear equivalences between modules. We only put the type classes that are necessary for the definition, although in applications
MandM₂will be topological modules over the topological semiringR.
Instances For
Continuous linear equivalences between modules. We only put the type classes that are necessary
for the definition, although in applications M and M₂ will be topological modules over the
topological semiring R.
Equations
- One or more equations did not get rendered due to their size.
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Continuous linear equivalences between modules. We only put the type classes that are necessary
for the definition, although in applications M and M₂ will be topological modules over the
topological semiring R.
Equations
- One or more equations did not get rendered due to their size.
Instances For
ContinuousSemilinearEquivClass F σ M M₂ asserts F is a type of bundled continuous
σ-semilinear equivs M → M₂. See also ContinuousLinearEquivClass F R M M₂ for the case
where σ is the identity map on R. A map f between an R-module and an S-module over a ring
homomorphism σ : R →+* S is semilinear if it satisfies the two properties f (x + y) = f x + f y
and f (c • x) = (σ c) • f x.
- map_continuous (f : F) : Continuous ⇑f
ContinuousSemilinearEquivClass F σ M M₂assertsFis a type of bundled continuousσ-semilinear equivsM → M₂. See alsoContinuousLinearEquivClass F R M M₂for the case whereσis the identity map onR. A mapfbetween anR-module and anS-module over a ring homomorphismσ : R →+* Sis semilinear if it satisfies the two propertiesf (x + y) = f x + f yandf (c • x) = (σ c) • f x. - inv_continuous (f : F) : Continuous (EquivLike.inv f)
ContinuousSemilinearEquivClass F σ M M₂assertsFis a type of bundled continuousσ-semilinear equivsM → M₂. See alsoContinuousLinearEquivClass F R M M₂for the case whereσis the identity map onR. A mapfbetween anR-module and anS-module over a ring homomorphismσ : R →+* Sis semilinear if it satisfies the two propertiesf (x + y) = f x + f yandf (c • x) = (σ c) • f x.
Instances
ContinuousLinearEquivClass F σ M M₂ asserts F is a type of bundled continuous
R-linear equivs M → M₂. This is an abbreviation for
ContinuousSemilinearEquivClass F (RingHom.id R) M M₂.
Equations
- ContinuousLinearEquivClass F R M M₂ = ContinuousSemilinearEquivClass F (RingHom.id R) M M₂
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A continuous linear equivalence induces a continuous linear map.
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Coerce continuous linear equivs to continuous linear maps.
Equations
A continuous linear equivalence induces a homeomorphism.
Equations
- e.toHomeomorph = { toEquiv := (↑e).toEquiv, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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An extensionality lemma for R ≃L[R] M.
A continuous linear equivalence seen as a ContinuousAddEquiv.
Equations
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The identity map as a continuous linear equivalence.
Equations
- ContinuousLinearEquiv.refl R₁ M₁ = { toLinearEquiv := LinearEquiv.refl R₁ M₁, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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The inverse of a continuous linear equivalence as a continuous linear equivalence
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See Note [custom simps projection]. We need to specify this projection explicitly in this case, because it is a composition of multiple projections.
Equations
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See Note [custom simps projection]
Equations
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The composition of two continuous linear equivalences as a continuous linear equivalence.
Equations
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Create a ContinuousLinearEquiv from two ContinuousLinearMaps that are
inverse of each other. See also equivOfInverse'.
ToDo: Improve the naming to make it match LinearEquiv.ofLinearMap.
Equations
- ContinuousLinearEquiv.equivOfInverse f₁ f₂ h₁ h₂ = { toLinearMap := ↑f₁, invFun := ⇑f₂, left_inv := h₁, right_inv := h₂, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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Create a ContinuousLinearEquiv from two ContinuousLinearMaps that are
inverse of each other, in the ContinuousLinearMap.comp sense. See also equivOfInverse.
ToDo: Improve the naming to make it match LinearEquiv.ofLinearMap
Equations
- ContinuousLinearEquiv.equivOfInverse' f₁ f₂ h₁ h₂ = ContinuousLinearEquiv.equivOfInverse f₁ f₂ ⋯ ⋯
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The inverse of equivOfInverse' is obtained by swapping the order of its parameters.
The continuous linear equivalences from M to itself form a group under composition.
Equations
- One or more equations did not get rendered due to their size.
The continuous linear equivalence between ULift M₁ and M₁.
This is a continuous version of ULift.moduleEquiv.
Equations
- ContinuousLinearEquiv.ulift = { toLinearEquiv := ULift.moduleEquiv, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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A pair of continuous (semi)linear equivalences generates an equivalence between the spaces of
continuous linear maps. See also ContinuousLinearEquiv.arrowCongr.
Equations
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A pair of continuous (semi)linear equivalences generates a linear equivalence between the spaces
of continuous linear maps. See also ContinuousLinearEquiv.arrowCongr.
Equations
- e₁₂.arrowCongrEquivₛₗ e₄₃ = { toFun := (e₁₂.arrowCongrEquiv e₄₃).toFun, map_add' := ⋯, map_smul' := ⋯, invFun := (e₁₂.arrowCongrEquiv e₄₃).invFun, left_inv := ⋯, right_inv := ⋯ }
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Scalar multiplication by a group element as a continuous linear equivalence.
Equations
- One or more equations did not get rendered due to their size.
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Automorphisms as continuous linear equivalences and as units of the ring of endomorphisms #
The next theorems cover the identification between M ≃L[R] M and the group of units of the ring
M →L[R] M.
An invertible continuous linear map f determines a continuous equivalence from M to itself.
Equations
- ContinuousLinearEquiv.ofUnit f = { toFun := ⇑↑f, map_add' := ⋯, map_smul' := ⋯, invFun := ⇑f.inv, left_inv := ⋯, right_inv := ⋯, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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A continuous equivalence from M to itself determines an invertible continuous linear map.
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The units of the algebra of continuous R-linear endomorphisms of M is multiplicatively
equivalent to the type of continuous linear equivalences between M and itself.
Equations
- ContinuousLinearEquiv.unitsEquiv R M = { toFun := ContinuousLinearEquiv.ofUnit, invFun := ContinuousLinearEquiv.toUnit, left_inv := ⋯, right_inv := ⋯, map_mul' := ⋯ }
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Units of a ring as linear automorphisms #
Continuous linear equivalences R ≃L[R] R are enumerated by Rˣ.
Equations
- One or more equations did not get rendered due to their size.
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Equivalence given by a block lower diagonal matrix. e and e' are diagonal square blocks,
and f is a rectangular block below the diagonal.
Equations
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The negation map as a continuous linear equivalence.
Equations
- ContinuousLinearEquiv.neg R = { toLinearEquiv := LinearEquiv.neg R, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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A pair of continuous linear maps such that f₁ ∘ f₂ = id generates a continuous
linear equivalence e between M and M₂ × f₁.ker such that (e x).2 = x for x ∈ f₁.ker,
(e x).1 = f₁ x, and (e (f₂ y)).2 = 0. The map is given by e x = (f₁ x, x - f₂ (f₁ x)).
Equations
- ContinuousLinearEquiv.equivOfRightInverse f₁ f₂ h = ContinuousLinearEquiv.equivOfInverse (f₁.prod (f₁.projKerOfRightInverse f₂ h)) (f₂.coprod (↑f₁).ker.subtypeL) ⋯ ⋯
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If M is an R-module and S-module and R-module structure is defined by an action of R on
S (formally, we have two scalar towers), then any S-linear equivalence on M is an R-linear
equivalence.
Equations
- ContinuousLinearEquiv.restrictScalars R f = { toLinearEquiv := LinearEquiv.restrictScalars R ↑f, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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The function op is a continuous linear equivalence.
Equations
- MulOpposite.opContinuousLinearEquiv R = { toLinearEquiv := MulOpposite.opLinearEquiv R, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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Left scalar multiplication of a unit and a continuous linear equivalence, as a continuous linear equivalence.
Equations
- One or more equations did not get rendered due to their size.
A linear equivalence that is a homeomorphism is a continuous linear equivalence.
Equations
- ContinuousLinearEquiv.ofIsHomeomorph f hf = { toLinearEquiv := f, continuous_toFun := ⋯, continuous_invFun := ⋯ }
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Alias of ContinuousLinearEquiv.toLinearEquiv_ofIsHomeomorph.
A linear equivalence between topological modules is a homeomorphism if and only if it is continuous in both directions.
ContinuousLinearEquiv.toLinearEquiv as a multiplicative monoid homomorphism MonoidHom.
Equations
- ContinuousLinearEquiv.toLinearEquivMonoidHom = { toFun := ContinuousLinearEquiv.toLinearEquiv, map_one' := ⋯, map_mul' := ⋯ }