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TauCeti.Geometry.Diffeomorphism.Evaluation

Continuous evaluation of diffeomorphisms #

On a compact source manifold with locally compact model, the weak Whitney topology makes evaluation of C^n diffeomorphisms continuous in both the diffeomorphism and the point. For self-diffeomorphisms this gives continuity of the tautological action, and evaluations at the two ends of a path in the source are homotopic (Diffeomorph.evalAtHomotopy).

theorem Diffeomorph.continuousEval_weakWhitney {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] {E : Type u_2} [NormedAddCommGroup E] [NormedSpace 𝕜 E] [LocallyCompactSpace E] {H : Type u_3} [TopologicalSpace H] {I : ModelWithCorners 𝕜 E H} {M : Type u_4} [TopologicalSpace M] [ChartedSpace H M] [CompactSpace M] {n : WithTop ℕ∞} [IsManifold I n M] {F : Type u_5} [NormedAddCommGroup F] [NormedSpace 𝕜 F] {G : Type u_6} [TopologicalSpace G] {J : ModelWithCorners 𝕜 F G} {N : Type u_7} [TopologicalSpace N] [ChartedSpace G N] [IsManifold J n N] :
ContinuousEval (Diffeomorph I J M N n) M N

Diffeomorphism evaluation is continuous for the weak Whitney topology.

The natural action of Diff(M) on M is continuous jointly in the diffeomorphism and the point.

noncomputable def Diffeomorph.evalAtHomotopy {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] {E : Type u_2} [NormedAddCommGroup E] [NormedSpace 𝕜 E] [LocallyCompactSpace E] {H : Type u_3} [TopologicalSpace H] {I : ModelWithCorners 𝕜 E H} {M : Type u_4} [TopologicalSpace M] [ChartedSpace H M] [CompactSpace M] {n : WithTop ℕ∞} [IsManifold I n M] {F : Type u_5} [NormedAddCommGroup F] [NormedSpace 𝕜 F] {G : Type u_6} [TopologicalSpace G] {J : ModelWithCorners 𝕜 F G} {N : Type u_7} [TopologicalSpace N] [ChartedSpace G N] [IsManifold J n N] {x₀ x₁ : M} (γ : Path x₀ x₁) :
(evalAt x₀).Homotopy (evalAt x₁)

Evaluations at two points joined by a path γ are homotopic, through evaluation along γ.

Instances For
    @[simp]
    theorem Diffeomorph.evalAtHomotopy_apply {𝕜 : Type u_1} [NontriviallyNormedField 𝕜] {E : Type u_2} [NormedAddCommGroup E] [NormedSpace 𝕜 E] [LocallyCompactSpace E] {H : Type u_3} [TopologicalSpace H] {I : ModelWithCorners 𝕜 E H} {M : Type u_4} [TopologicalSpace M] [ChartedSpace H M] [CompactSpace M] {n : WithTop ℕ∞} [IsManifold I n M] {F : Type u_5} [NormedAddCommGroup F] [NormedSpace 𝕜 F] {G : Type u_6} [TopologicalSpace G] {J : ModelWithCorners 𝕜 F G} {N : Type u_7} [TopologicalSpace N] [ChartedSpace G N] [IsManifold J n N] {x₀ x₁ : M} (γ : Path x₀ x₁) (p : ↑unitInterval × Diffeomorph I J M N n) :
    (evalAtHomotopy γ) p = p.2 (γ p.1)

    At time t, the homotopy evalAtHomotopy γ evaluates at γ t.