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Project-declaredLean 4.29.0-rc6 · mathlib@5c8398df5281

Mem W01p of cont Diff has Compact Support subset

DeGiorgi.memW01p_of_contDiff_hasCompactSupport_subset

Plain-language statement

A smooth compactly supported function whose support is contained in an open set belongs to W₀^{1,p} on that set.

Exact Lean statement

theorem memW01p_of_contDiff_hasCompactSupport_subset
    {p : ℝ≥0∞} {Ω : Set E} (hΩ : IsOpen Ω) {f : E → ℝ}
    (hf : ContDiff ℝ (⊤ : ℕ∞) f) (hf_supp : HasCompactSupport f)
    (hf_sub : tsupport f ⊆ Ω) :
    MemW01p p f Ω

Formal artifact

Lean source

Canonical source
Full Lean sourceLean 4
theorem memW01p_of_contDiff_hasCompactSupport_subset    {p : 0∞} {Ω : Set E} (hΩ : IsOpen Ω) {f : E  }    (hf : ContDiff  (⊤ : ∞) f) (hf_supp : HasCompactSupport f)    (hf_sub : tsupport f  Ω) :    MemW01p p f Ω := by  let _ := (inferInstance : NeZero d)  let hw : MemW1pWitness p f Ω :=    { memLp := (hf.continuous.memLp_of_hasCompactSupport hf_supp).restrict Ω      weakGrad := fun x =>        WithLp.toLp 2 fun i => (fderiv  f x) (EuclideanSpace.single i 1)      weakGrad_component_memLp := by        intro i        have hderiv_smooth : ContDiff  (⊤ : ∞)            (fun x => (fderiv  f x) (EuclideanSpace.single i 1)) :=          (hf.fderiv_right (m := (⊤ : ∞)) (by norm_cast)).clm_apply contDiff_const        exact (hderiv_smooth.continuous.memLp_of_hasCompactSupport          (hf_supp.fderiv_apply (𝕜 := ) _)).restrict Ω      isWeakGrad := by        intro i        simpa [PiLp.toLp_apply] using          (HasWeakPartialDeriv.of_contDiff:= Ω) (i := i)            (f := f) hΩ (hf.of_le (by norm_cast))) }  refine hw.memW1p, hw, fun _ => f, ?_, ?_, ?_, ?_, ?_  · intro n    exact hf  · intro n    exact hf_supp  · intro n    exact hf_sub  · simp  · intro i    simp [hw]
Project
DeGiorgi
License
Apache-2.0
Commit
4c1b3077d378
Source
DeGiorgi/SobolevSpace/Witnesses.lean:542-573

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Project-declaredLean 4.29.0-rc6

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partial differential equationsregularity theoryanalysis

Source project: DeGiorgi

Person-level attribution pending.

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Project-declaredLean 4.29.0-rc6

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Plain-language statement

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partial differential equationsregularity theoryanalysis

Source project: DeGiorgi

Person-level attribution pending.

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Project-declaredLean 4.29.0-rc6

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Plain-language statement

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partial differential equationsregularity theoryanalysis

Source project: DeGiorgi

Person-level attribution pending.

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