2023/12/18 by Kim, Hyunseok, Phan, Tuoc, Tsai, Tai-Peng · 1 citation
#35J15 #35J25 #Analysis of PDEs (math.AP) #FOS: Mathematics
paper · doi:10.48550/arxiv.2312.11215
We study the Dirichlet problem for a second order linear elliptic equation in a bounded smooth domain Ω in ℝn, n ≥ 3, with the drift b belonging to the critical weak space Ln,∞(Ω). We decompose the drift b = b1 + b2 in which div b1 ≥ 0 and b2 is small only in a small scale quasi-norm of Ln,∞(Ω). Under this new smallness condition, we prove existence, uniqueness, and regularity estimates of weak solutions to the problem and its dual. Hölder regularity and derivative estimates of weak solutions to the dual problem are also established. As a result, we prove uniqueness of very weak solutions slightly below the threshold. When b2 =0, our results recover those by Kim and Tsai in [SIAM J. Math. Anal. 52 (2020)]. Due to the new small scale quasi-norm, our results are new even when b1=0.