Smoothness of regularized L² fields #
Convolution by the fixed smooth compactly supported mollifier maps every spatial L² field into a smooth coordinate field. The input need not be divergence free when it is a difference in the local Lipschitz estimate.
theorem
CKN.Leray.regUniformMollifiedInitial_contDiff_of_memLp
(ρ : RegMollifierProfile)
(ε : ℝ)
(hε : 0 < ε)
{a : Foundation.Parabolic.Vec3 → Foundation.Parabolic.Vec3}
(ha : MeasureTheory.MemLp a 2 MeasureTheory.volume)
:
ContDiff ℝ (↑⊤) (regUniformMollifiedInitial ρ ε hε a)
Mollification of an arbitrary coordinate L² field is spatially smooth.