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Mathlib.Analysis.Calculus.TangentCone.Pi

Indexed product of sets with unique differentiability property #

In this file we prove that the indexed product of a family sets with unique differentiability property has the same property, see UniqueDiffOn.pi and UniqueDiffOn.univ_pi.

theorem mapsTo_tangentConeAt_pi {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] {ι : Type u_2} {E : ιType u_3} [(i : ι) → NormedAddCommGroup (E i)] [(i : ι) → NormedSpace 𝕜 (E i)] {s : (i : ι) → Set (E i)} {x : (i : ι) → E i} [DecidableEq ι] {i : ι} (hi : ∀ (j : ι), j ix j closure (s j)) :
Set.MapsTo (⇑(LinearMap.single 𝕜 E i)) (tangentConeAt 𝕜 (s i) (x i)) (tangentConeAt 𝕜 (Set.univ.pi s) x)

The tangent cone of a product contains the tangent cone of each factor.

@[deprecated mapsTo_tangentConeAt_pi (since := "2025-04-27")]
theorem mapsTo_tangentCone_pi {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] {ι : Type u_2} {E : ιType u_3} [(i : ι) → NormedAddCommGroup (E i)] [(i : ι) → NormedSpace 𝕜 (E i)] {s : (i : ι) → Set (E i)} {x : (i : ι) → E i} [DecidableEq ι] {i : ι} (hi : ∀ (j : ι), j ix j closure (s j)) :
Set.MapsTo (⇑(LinearMap.single 𝕜 E i)) (tangentConeAt 𝕜 (s i) (x i)) (tangentConeAt 𝕜 (Set.univ.pi s) x)

Alias of mapsTo_tangentConeAt_pi.


The tangent cone of a product contains the tangent cone of each factor.

theorem UniqueDiffWithinAt.univ_pi {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] (ι : Type u_2) (E : ιType u_3) [(i : ι) → NormedAddCommGroup (E i)] [(i : ι) → NormedSpace 𝕜 (E i)] [Finite ι] (s : (i : ι) → Set (E i)) (x : (i : ι) → E i) (h : ∀ (i : ι), UniqueDiffWithinAt 𝕜 (s i) (x i)) :
theorem UniqueDiffWithinAt.pi {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] (ι : Type u_2) (E : ιType u_3) [(i : ι) → NormedAddCommGroup (E i)] [(i : ι) → NormedSpace 𝕜 (E i)] [Finite ι] (s : (i : ι) → Set (E i)) (x : (i : ι) → E i) (I : Set ι) (h : iI, UniqueDiffWithinAt 𝕜 (s i) (x i)) :
UniqueDiffWithinAt 𝕜 (I.pi s) x
theorem UniqueDiffOn.pi {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] (ι : Type u_2) (E : ιType u_3) [(i : ι) → NormedAddCommGroup (E i)] [(i : ι) → NormedSpace 𝕜 (E i)] [Finite ι] (s : (i : ι) → Set (E i)) (I : Set ι) (h : iI, UniqueDiffOn 𝕜 (s i)) :
UniqueDiffOn 𝕜 (I.pi s)

The finite product of a family of sets of unique differentiability is a set of unique differentiability.

theorem UniqueDiffOn.univ_pi {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] (ι : Type u_2) (E : ιType u_3) [(i : ι) → NormedAddCommGroup (E i)] [(i : ι) → NormedSpace 𝕜 (E i)] [Finite ι] (s : (i : ι) → Set (E i)) (h : ∀ (i : ι), UniqueDiffOn 𝕜 (s i)) :

The finite product of a family of sets of unique differentiability is a set of unique differentiability.