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LeanPool.NavierStokesAndEuler.Euler.MeanTimeTranslation

Actual spatial translations of the fixed mean time space #

Translation preserves ordinary solenoidal L² and its Bochner time space. The action is isometric and strongly continuous and commutes with the actual terminal primitive and initial trace.

Strong continuity of isometric spatial actions on time L² #

This uses dominated convergence with the actual square-integrable time field. It does not assume operator-norm continuity of spatial translations.

theorem EulerTimeLpBoundedMap.timeLift_norm_sub_sq {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] (T : ℝ) (A B : E →L[ℝ] E) (u : ↥(EulerTimeLp.TimeLp T E)) :
‖(timeLift T A) u - (timeLift T B) u‖ ^ 2 = ∫ (t : ℝ), ‖A (↑↑u t) - B (↑↑u t)‖ ^ 2 ∂EulerTimeLp.timeMeasure T

A pointwise formula for the square distance between two genuine lifted fields.

theorem EulerTimeLpBoundedMap.timeLift_strongly_continuous {E : Type u_1} [NormedAddCommGroup E] [NormedSpace ℝ E] {X : Type u_2} [TopologicalSpace X] [FirstCountableTopology X] (T : ℝ) (A : X → E →L[ℝ] E) (hA : ∀ (x : X) (v : E), ‖(A x) v‖ = ‖v‖) (hc : ∀ (v : E), Continuous fun (x : X) => (A x) v) (u : ↥(EulerTimeLp.TimeLp T E)) :
Continuous fun (x : X) => (timeLift T (A x)) u

A strongly continuous family of spatial isometries remains strongly continuous on the genuine Bochner time space.

Spatial translation restricted to the actual ordinary solenoidal space.

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Instances For

    Strong continuity is proved for every ordinary L² equivalence class.

    The same strong continuity holds on the closed solenoidal subspace.

    The actual spatial action is continuous in translation for every time-L² field.