2015/10/03 by Denny Otten, Otten, Denny
Mathematics · #35A02 #35J47 (35K57 #47A05 #47A10 #47B44) #Analysis of PDEs (math.AP) #FOS: Mathematics #math.AP #msc:35A02 #msc:35J47 #msc:47A05 #msc:47A10
paper · pdf · doi:10.48550/arxiv.1510.00827
32 pages
arxiv created 2015/10/03 · arxiv updated 2015/10/06
In this paper we study perturbed Ornstein-Uhlenbeck operators [L∞ v](x)=A\triangle v(x)+⟨ Sx,∇ v(x)⟩-B v(x), x∈ℝd, d\geqslant 2, for simultaneously diagonalizable matrices A,B∈ℂN,N. The unbounded drift term is defined by a skew-symmetric matrix S∈ℝd,d. Differential operators of this form appear when investigating rotating waves in time-dependent reaction diffusion systems. We prove under certain conditions that the maximal domain D(Ap) of the generator Ap belonging to the Ornstein-Uhlenbeck semigroup coincides with the domain of L∞ in Lp(ℝd,ℂN) given by Dploc(L0)=\v∈ W2,ploc∩ Lp| A\triangle v+⟨ S⋅,∇ v⟩∈ Lp\, 1<p<∞. One key assumption is a new Lp-antieigenvalue condition μ1(A) > (|p-2|)/(p), 1<p<∞, μ1(A) first antieigenvalue of A. The proof utilizes the following ingredients. First we show the closedness of L∞ in Lp and derive Lp-resolvent estimates for L∞. Then we prove that the Schwartz space is a core of Ap and apply an Lp-solvability result of the resolvent equation for Ap. A second characterization shows that the maximal domain even coincides with Dpmax(L0)=\v∈ W2,p| ⟨ S⋅,∇ v⟩∈ Lp\, 1<p<∞. This second characterization is based on the first one, and its proof requires Lp-regularity for the Cauchy problem associated with Ap. Finally, we show a W2,p-resolvent estimate for L∞ and an Lp-estimate for the drift term ⟨ S⋅,∇ v⟩.