OAI/Geometry/EinsteinFour/ScalarLpNormVariation.lean
6 declarations, 0 contain sorry, 0 declared as axioms
The squared Lp norm at a normalized function has the expected first variation, including for sign-changing or merely Lp representatives.
- theorem
OAI.PositiveEinsteinFour.Geometry.scalarLp_norm_eq_momentline 19Source documentation
The ordinary real Lp norm as an integral of the actual representative.
theorem scalarLp_norm_eq_moment {p : ℝ} [Fact (1 ≤ ENNReal.ofReal p)] (hp : 0 < p) (f : Lp ℝ (ENNReal.ofReal p) μ) : ‖f‖ = (∫ x, |f x| ^ p ∂μ) ^ p⁻¹ := by … - theorem
OAI.PositiveEinsteinFour.Geometry.scalarLp_moment_eq_norm_rpowline 27 - theorem
OAI.PositiveEinsteinFour.Geometry.scalarLp_norm_sq_eq_momentline 33 - theorem
OAI.PositiveEinsteinFour.Geometry.scalarLp_add_smul_momentline 40 - theorem
OAI.PositiveEinsteinFour.Geometry.scalarLpNormSq_hasDerivAtline 52Source documentation
At Lp norm one, the squared norm differentiates to twice the nonlinear pairing against a bounded measurable direction.
theorem scalarLpNormSq_hasDerivAt {p : ℝ} [Fact (1 ≤ ENNReal.ofReal p)] (hp : 2 < p) (f b : Lp ℝ (ENNReal.ofReal p) μ) (hf : ‖f‖ = 1) {B : ℝ} (hB : 0 ≤ B) (hb : ∀ᵐ x ∂μ, |b x| ≤ B) : HasDerivAt (fun t : ℝ => ‖f + t • b‖ ^ 2) (2 * ∫ x, |f x| ^ (p - 2) * f x * b x ∂μ) 0 := by … - theorem
OAI.PositiveEinsteinFour.Geometry.scalarLpNormSq_hasDerivAt_continuousline 74Source documentation
A continuous representative of the direction is sufficient; no regularity or pointwise sign is required of the normalized Lp function.
theorem scalarLpNormSq_hasDerivAt_continuous [TopologicalSpace X] [OpensMeasurableSpace X] [CompactSpace X] {p : ℝ} [Fact (1 ≤ ENNReal.ofReal p)] (hp : 2 < p) (f b : Lp ℝ (ENNReal.ofReal p) μ) (hf : ‖f‖ = 1) (v : C(X, ℝ)) (hb : (b : X → ℝ) =ᵐ[μ] v) : HasDerivAt (fun t : ℝ => ‖f + t • b‖ ^ 2) (2 * ∫ x, |f x| ^ (p - 2) * f x * v x ∂μ) 0 := by …