We prove Lp-Lq estimates of the Oseen semigroup in n-dimensional exterior domains (n 3), which refine and improve those obtained by Kobayashi and Shibata [15]. As an application, we give a globally in time stability theory for the stationary Navier-Stokes flow whose velocity at infinity is a non-zero constant vector. We thus extend the result of Shibata [21]. In particular, we find an optimal rate of convergence of solutions of the non-stationary problem to those of the corresponding stationary problem. (2000). 35B40, 35M20, 73B30.
Mathematics Subject Classification