2017/03/03 by Tolksdorf, Patrick · 3 citations
#Analysis of PDEs (math.AP) #FOS: Mathematics #Functional Analysis (math.FA)
paper · doi:10.48550/arxiv.1703.01091
On a bounded Lipschitz domain Ω⊂ ℝd, d ≥ 3, we continue the study of Shen and of Kunstmann and Weis of the Stokes operator on Lpσ (Ω). We employ their results in order to determine the domain of the square root of the Stokes operator as the space W1 , p0 , σ (Ω) for | (1)/(p) - (1)/(2) | < (1)/(d) + ε and some ε > 0. This characterization provides gradient estimates as well as Lp-Lq-mapping properties of the corresponding semigroup. In the three-dimensional case this provides a means to show the existence of solutions to the Navier--Stokes equations in the critical space L∞ (0 , ∞ ; L3σ (Ω)) whenever the initial velocity is small in the L3-norm. Finally, we present a different approach to the Lp-theory of the Navier--Stokes equations by employing the maximal regularity proven by Kunstmann and Weis.