Documentation

LeanPool.NavierStokesAndEuler.Euler.SobolevMaximalRegularity

Genuine all-finite-order maximal regularity for actual viscous cylinder mild solutions.

Actual maximal regularity at arbitrary finite Sobolev order via finitely many top derivative equations.

A genuine L²-time H² estimate for regularized heat solutions, with only L² forcing.

Genuine gradient energy and maximal-regularity estimates for smooth Sobolev heat solutions.

noncomputable def EulerHeatGradientEnergy.gradientEnergy (period : ) [Fact (0 < period)] (u : (EulerCylinderSobolevSpace.SobolevSpace period 1)) :

The actual sum of the four first-derivative L² energies.

Equations
Instances For

    Gradient energy is nonnegative.

    Gradient energy is a continuous function of the actual H¹ field.

    Genuine strong-derivative integration by parts identifies the full gradient pairing with the Laplacian.

    Actual L² time derivatives of the first spatial derivatives determine the gradient-energy derivative.

    theorem EulerHeatGradientEnergy.viscosity_young (ν x y : ) ( : 0 < ν) :
    2 * x * y ν * x ^ 2 + ν⁻¹ * y ^ 2

    The scalar Young bound with the exact viscosity scaling used by maximal regularity.

    The actual derivative of gradient energy controls the full L² Laplacian with no source derivative loss.

    A genuine H² bound by H¹ and the cylinder Laplacian, used in strong maximal-regularity limits.

    Exact L² Hessian coercivity from actual commuting strong derivatives.

    noncomputable def EulerHeatGradientEnergy.hessianEnergy (period : ) [Fact (0 < period)] (u : (EulerCylinderSobolevSpace.SobolevSpace period 2)) :

    The actual sum of all sixteen second-coordinate L² energies.

    Equations
    • One or more equations did not get rendered due to their size.
    Instances For

      All genuine second-coordinate derivatives are controlled exactly by the Laplacian.

      Every actual second derivative word is bounded by the full genuine Hessian energy.

      The complete H² norm is controlled by its H¹ restriction and the actual Hessian energy.

      Integrated genuine heat gradient energy, with the source measured only in L².

      The actual integrated heat energy gains the full Laplacian in L² time without a source derivative in the bound.

      The actual gradient energy is bounded by four times the complete H¹ norm squared.

      theorem EulerHeatMaximalEstimate.integral_le_constant_add (f g : ) (c T : ) (hT : 0 T) (hf : Continuous f) (hg : Continuous g) (hfg : tSet.Icc 0 T, f t c + g t) :
      (t : ) in 0..T, f t T * c + (t : ) in 0..T, g t

      Integrating a continuous scalar upper bound by a constant plus another continuous function.

      Strong Cauchy convergence from a quadratic norm estimate in complete-space arguments.

      theorem EulerQuadraticCauchy.transport_quadratic_bound {X : Type u_1} {Y : Type u_2} {Z : Type u_3} [NormedAddCommGroup X] [NormedAddCommGroup Y] [NormedAddCommGroup Z] (a b : ) (x x' : X) (y y' : Y) (z z' : Z) (hx : x = x') (hy : y = y') (hz : z = z') (h : x ^ 2 a * y ^ 2 + b * z ^ 2) :
      x' ^ 2 a * y' ^ 2 + b * z' ^ 2

      Replacing three vectors by equal vectors preserves a quadratic norm estimate.

      theorem EulerQuadraticCauchy.limit_quadratic_bound {X : Type u_1} {Y : Type u_2} {Z : Type u_3} [NormedAddCommGroup X] [NormedAddCommGroup Y] [NormedAddCommGroup Z] (U : X) (F : Y) (V : Z) (u : X) (f : Y) (v : Z) (a b : ) (hu : Filter.Tendsto U Filter.atTop (nhds u)) (hf : Filter.Tendsto F Filter.atTop (nhds f)) (hv : Filter.Tendsto V Filter.atTop (nhds v)) (hb : ∀ (n : ), V n ^ 2 a * U n ^ 2 + b * F n ^ 2) :
      v ^ 2 a * u ^ 2 + b * f ^ 2

      A quadratic norm estimate passes to actual strong limits in three normed spaces.

      theorem EulerQuadraticCauchy.cauchy_of_quadratic_bound {X : Type u_1} {Y : Type u_2} {Z : Type u_3} [NormedAddCommGroup X] [NormedAddCommGroup Y] [NormedAddCommGroup Z] (U : X) (F : Y) (V : Z) (a b : ) (hu : CauchySeq U) (hf : CauchySeq F) (hb : ∀ (n m : ), V n - V m ^ 2 a * U n - U m ^ 2 + b * F n - F m ^ 2) :

      A sequence whose squared differences are bounded by two Cauchy-sequence differences is Cauchy.

      Strong L²-time H² Cauchy convergence from genuine heat energy, avoiding weak compactness.

      @[instance_reducible]
      noncomputable def EulerHeatMaximalCauchy.instSobolevPathSub (period : ) [Fact (0 < period)] (T : ) (k : ) :

      Cache pointwise subtraction for the Sobolev paths used in difference estimates.

      Equations
      Instances For
        @[instance_reducible]
        noncomputable def EulerHeatMaximalCauchy.instSobolevScalarAction (period : ) [Fact (0 < period)] (k : ) :

        Cache the scalar action used by the Sobolev heat equations.

        Equations
        Instances For
          theorem EulerHeatMaximalCauchy.linear_heat_rhs_sub {X : Type u_1} {Y : Type u_2} {Z : Type u_3} [NormedAddCommGroup X] [NormedSpace X] [NormedAddCommGroup Y] [NormedSpace Y] [NormedAddCommGroup Z] [NormedSpace Z] (L : Y →L[] Z) (A : X →L[] Y) (ν : ) (u v : X) (f g : Y) :
          L (ν A (u - v) + (f - g)) = L (ν A u + f) - L (ν A v + g)

          A bounded linear observation preserves the difference form of the forced heat right hand side.

          theorem EulerHeatMaximalCauchy.first_derivative_difference (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) (u v : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) (f g : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (t : ) (i : Fin 4) (hu : HasDerivAt (fun (s : ) => EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 2 i) (EulerVolterraConvolution.extendPath T hT u s))) (EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 0 i) (ν (EulerSobolevLaplacian.laplacianOperator period 1) (EulerVolterraConvolution.extendPath T hT u t) + EulerVolterraConvolution.extendPath T hT f t))) t) (hv : HasDerivAt (fun (s : ) => EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 2 i) (EulerVolterraConvolution.extendPath T hT v s))) (EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 0 i) (ν (EulerSobolevLaplacian.laplacianOperator period 1) (EulerVolterraConvolution.extendPath T hT v t) + EulerVolterraConvolution.extendPath T hT g t))) t) :

          The difference of two actual differentiated heat equations is the same linear equation with difference source.

          noncomputable def EulerHeatMaximalCauchy.lowerPath (period : ) [Fact (0 < period)] (T : ) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) :

          Restrict a regularized path to its actual H¹ topology.

          Equations
          • One or more equations did not get rendered due to their size.
          Instances For
            noncomputable def EulerHeatMaximalCauchy.higherTime (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) :

            Embed the actual H² restriction of a regularized path into L² time.

            Equations
            • One or more equations did not get rendered due to their size.
            Instances For
              noncomputable def EulerHeatMaximalCauchy.sourceTime (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) :

              Embed the actual undifferentiated forcing into L² time.

              Equations
              Instances For
                theorem EulerHeatMaximalCauchy.lowerPath_sub (period : ) [Fact (0 < period)] (T : ) (u v : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) :
                lowerPath period T (u - v) = lowerPath period T u - lowerPath period T v

                The lower path restriction preserves differences.

                theorem EulerHeatMaximalCauchy.higherTime_sub (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (u v : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) :
                higherTime period T hT (u - v) = higherTime period T hT u - higherTime period T hT v

                The actual higher time embedding preserves differences.

                theorem EulerHeatMaximalCauchy.sourceTime_sub (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (f g : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) :
                sourceTime period T hT (f - g) = sourceTime period T hT f - sourceTime period T hT g

                The actual source time embedding preserves differences.

                theorem EulerHeatMaximalCauchy.heat_H2_difference_bound (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) ( : 0 < ν) (u v : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) (f g : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (hd : tSet.Ioo 0 T, ∀ (i : Fin 4), HasDerivAt (fun (s : ) => EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 2 i) (EulerVolterraConvolution.extendPath T hT (u - v) s))) (EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 0 i) (ν (EulerSobolevLaplacian.laplacianOperator period 1) (EulerVolterraConvolution.extendPath T hT (u - v) t) + EulerVolterraConvolution.extendPath T hT (f - g) t))) t) :
                higherTime period T hT u - higherTime period T hT v ^ 2 (T + 4 * ν⁻¹) * lowerPath period T u - lowerPath period T v ^ 2 + ν⁻¹ ^ 2 * sourceTime period T hT f - sourceTime period T hT g ^ 2

                The true linear heat equation controls actual H² time differences by lower path and source differences.

                Actual regularized heat solutions which converge in H¹ and have Cauchy L² sources converge strongly in L² time with two full derivatives.

                theorem EulerHeatMaximalCauchy.exists_heat_H2_limit (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) ( : 0 < ν) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 3))) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (hd : ∀ (n : ), tSet.Ioo 0 T, ∀ (i : Fin 4), HasDerivAt (fun (s : ) => EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 2 i) (EulerVolterraConvolution.extendPath T hT (u n) s))) (EulerCylinderSobolevSpace.value period ((EulerCylinderSobolevSpace.derivativeOperator period 0 i) (ν (EulerSobolevLaplacian.laplacianOperator period 1) (EulerVolterraConvolution.extendPath T hT (u n) t) + EulerVolterraConvolution.extendPath T hT (f n) t))) t) (hu : CauchySeq fun (n : ) => (ContinuousLinearMap.compLeftContinuous (↑(Set.Icc 0 T)) (EulerCylinderSobolevSpace.restrictOperator period EulerHeatGradientEnergy.heat_gradient_energy_hasDerivAt._proof_1)) (u n)) (hf : CauchySeq fun (n : ) => EulerTimeLp.pathLp T hT ((ContinuousLinearMap.compLeftContinuous (↑(Set.Icc 0 T)) (EulerCylinderSobolevSpace.valueOperator period 1)) (f n))) :

                Completeness constructs a genuine Bochner L²-time H² limit of the regularized heat solutions.

                Actual higher Sobolev norms controlled by lower norms and finitely many top derivative blocks.

                theorem EulerSobolevTopBlocks.top_word_block (period : ) [Fact (0 < period)] (q : ) (u : (EulerCylinderSobolevSpace.SobolevSpace period (2 + q))) (w : Fin (2 + q)Fin 4) :
                EulerCylinderSobolevSpace.word period u w = EulerCylinderSobolevSpace.word period ((EulerSobolevWordBlocks.wordBlock period 2 q fun (i : Fin q) => w (Fin.natAdd 2 i)) u) fun (i : Fin 2) => w (Fin.castAdd q i)

                A full top derivative is literally a second derivative of one of the genuine top word blocks.

                theorem EulerSobolevTopBlocks.top_blocks_norm_sq (period : ) [Fact (0 < period)] (q : ) (u : (EulerCylinderSobolevSpace.SobolevSpace period (2 + q))) :

                The genuine complete H^(q+2) norm is controlled by H^(q+1) and all order-q H² derivative blocks.

                Strong time-space completion controlled by genuine finite spatial derivative blocks.

                theorem EulerTopBlockTimeNorm.pathLp_quadratic_bound {X : Type u_1} {Y : Type u_2} {Z : Type u_3} {I : Type u_4} [Fintype I] [NormedAddCommGroup X] [NormedSpace X] [NormedAddCommGroup Y] [NormedSpace Y] [NormedAddCommGroup Z] [NormedSpace Z] (A : X →L[] Y) (B : IX →L[] Z) (hb : ∀ (x : X), x ^ 2 A x ^ 2 + i : I, (B i) x ^ 2) (T : ) (hT : 0 T) (u : C((Set.Icc 0 T), X)) :

                Integration preserves a finite quadratic norm comparison between bounded spatial observations.

                All actual order-q H² blocks and the lower H^(q+1) norm control the full H^(q+2) time norm.

                Actual strong L²-time completion from finitely many closed derivative blocks.

                Strong Cauchy convergence controlled by finitely many genuine norm observations.

                theorem EulerQuadraticCauchy.cauchy_of_finite_quadratic_bound {X : Type u_1} {Y : Type u_2} {Z : Type u_3} {I : Type u_4} [Fintype I] [NormedAddCommGroup X] [NormedAddCommGroup Y] [NormedAddCommGroup Z] (U : X) (F : IY) (V : Z) (hu : CauchySeq U) (hf : ∀ (i : I), CauchySeq (F i)) (hb : ∀ (n m : ), V n - V m ^ 2 U n - U m ^ 2 + i : I, F i n - F i m ^ 2) :

                A finite family of Cauchy observations controlling squared differences forces a sequence to be Cauchy.

                Bounded spatial observation and actual time embedding preserve subtraction together.

                theorem EulerTopBlockTimeNorm.pathLp_quadratic_difference {X : Type u_1} {Y : Type u_2} {Z : Type u_3} {I : Type u_4} [Fintype I] [NormedAddCommGroup X] [NormedSpace X] [NormedAddCommGroup Y] [NormedSpace Y] [NormedAddCommGroup Z] [NormedSpace Z] (A : X →L[] Y) (B : IX →L[] Z) (hb : ∀ (x : X), x ^ 2 A x ^ 2 + i : I, (B i) x ^ 2) (T : ) (hT : 0 T) (u v : C((Set.Icc 0 T), X)) :

                The integrated genuine spatial block bound also controls time-space differences.

                theorem EulerTopBlockTimeNorm.cauchy_pathLp_of_blocks {X : Type u_1} {Y : Type u_2} {Z : Type u_3} {I : Type u_4} [Fintype I] [NormedAddCommGroup X] [NormedSpace X] [NormedAddCommGroup Y] [NormedSpace Y] [NormedAddCommGroup Z] [NormedSpace Z] (A : X →L[] Y) (B : IX →L[] Z) (hb : ∀ (x : X), x ^ 2 A x ^ 2 + i : I, (B i) x ^ 2) (T : ) (hT : 0 T) (u : C((Set.Icc 0 T), X)) (hu : CauchySeq fun (n : ) => EulerTimeLp.pathLp T hT ((ContinuousLinearMap.compLeftContinuous (↑(Set.Icc 0 T)) A) (u n))) (hf : ∀ (i : I), CauchySeq fun (n : ) => EulerTimeLp.pathLp T hT ((ContinuousLinearMap.compLeftContinuous (↑(Set.Icc 0 T)) (B i)) (u n))) :
                CauchySeq fun (n : ) => EulerTimeLp.pathLp T hT (u n)

                Genuine finite block convergence and lower-order convergence construct strong convergence in the full Bochner Sobolev space.

                Genuine maximal spatial regularity of the actual viscous mild solution, proved by strong Cauchy limits.

                theorem EulerHeatMaximalRegularity.regularized_mild_cauchy (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) ( : 0 < ν) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period 1)) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 0))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period 1 (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period 0 ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                The actual regularized mild solutions are strongly Cauchy in Bochner L² time with two derivatives.

                The strong higher-order limit has exactly the original lower-order field almost everywhere in time.

                The genuine heat estimate passes to the strong higher-order time limit without weak compactness.

                Completeness of actual H² Bochner space constructs its strong Cauchy limit.

                theorem EulerHeatMaximalRegularity.exists_regularized_mild_limit (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) ( : 0 < ν) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period 1)) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 0))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period 1 (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period 0 ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                Strong completion constructs the higher-order limit of the concrete mild-solution approximations.

                theorem EulerHeatMaximalRegularity.viscous_mild_maximal_regularity (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) ( : 0 < ν) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period 1)) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 0))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period 1 (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period 0 ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                The actual viscous mild solution with H¹ values and continuous L² source has two full spatial derivatives in L² time. The higher-regularity element is constructed in the complete Bochner space and identified with the original field almost everywhere.

                theorem EulerHeatMaximalRegularity.viscous_mild_ae_H2 (period : ) [Fact (0 < period)] (T : ) (hT : 0 T) (ν : ) ( : 0 < ν) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period 1)) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 0))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period 1))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period 1 (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period 0 ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                Actual H² spatial representatives exist for almost every time of the genuine H¹ viscous mild solution.

                The top block norm estimate in the original q+1 indexing used by actual mild solutions.

                theorem EulerMaximalTopCauchy.maximalApproximation_word_cauchy (period : ) [Fact (0 < period)] {q : } (ν : ) ( : 0 < ν) (T : ) (hT : 0 T) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period (q + 1))) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period q))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period (q + 1)))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period (q + 1) (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period q ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) (w : Fin qFin 4) :

                Every actual top-word regularization is strongly Cauchy in time with its two full extra spatial derivatives.

                theorem EulerMaximalTopCauchy.maximalApproximation_cauchy (period : ) [Fact (0 < period)] {q : } (ν : ) ( : 0 < ν) (T : ) (hT : 0 T) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period (q + 1))) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period q))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period (q + 1)))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period (q + 1) (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period q ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                The genuine full H^(q+2) heat regularizations form a strong Bochner Cauchy sequence, with no assumed derivative bound.

                The complete actual Bochner Sobolev space realizes every strong Cauchy sequence.

                theorem EulerSobolevMaximalRegularity.exists_maximal_mild_limit (period : ) [Fact (0 < period)] {q : } (ν : ) ( : 0 < ν) (T : ) (hT : 0 T) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period (q + 1))) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period q))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period (q + 1)))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period (q + 1) (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period q ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                Completion supplies the genuine higher-order limit of the actual viscous approximations.

                The actual higher-order limit restricts to the original viscous solution almost everywhere.

                theorem EulerSobolevMaximalRegularity.viscous_mild_maximal_regularity (period : ) [Fact (0 < period)] {q : } (ν : ) ( : 0 < ν) (T : ) (hT : 0 T) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period (q + 1))) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period q))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period (q + 1)))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period (q + 1) (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period q ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                Actual viscous mild solutions with continuous Hq forcing and H^(q+1) values possess full H^(q+2) regularity in Bochner L² time. The stronger field is constructed from genuine heat approximations and identified with the original field almost everywhere.

                theorem EulerSobolevMaximalRegularity.viscous_mild_ae_higher (period : ) [Fact (0 < period)] {q : } (ν : ) ( : 0 < ν) (T : ) (hT : 0 T) (u₀ : (EulerCylinderSobolevSpace.SobolevSpace period (q + 1))) (f : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period q))) (u : C((Set.Icc 0 T), (EulerCylinderSobolevSpace.SobolevSpace period (q + 1)))) (hsol : ∀ (t : (Set.Icc 0 T)), u t = (EulerSobolevHeat.heatOperator period (q + 1) (2 * ν * t).toNNReal) u₀ + (r : ) in 0..t, (EulerSobolevHeat.heatKernel period q ν r) (EulerVolterraConvolution.extendPath T hT f (t - r))) :

                The genuine full higher-order spatial derivatives exist at almost every time of the actual viscous solution.