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Acta Mathematica Vietnamica

A General Estimate for the ¯-Neumann Problem

icon-email Tran Vu Khanh

Abstract

This paper especially focuses on a general estimate, called  (fM)k, for the ¯-Neumann problem

(fM)kf(Λ)Mu2c(¯u2+¯u2+u2)+CMu12

for any uCc(UΩ¯)kDom(¯), where f(Λ) is the tangential pseudodifferential operator with symbol f((1+|ξ|2)12)M is a multiplier, and U is a neighborhood of a given boundary point z0. Here the domain Ω is q-pseudoconvex or q-pseudoconcave at z0. We want to point out that under a suitable choice of f and M(fM)k is the subelliptic, superlogarithmic, compactness and so on. Generalizing the Property (P) by Catlin (1984), we define Property (fMP)k. The result we obtain in here is: Property (fMP)k yields the (fM)k estimate. The paper also aims at exhibiting some relevant classes of domains which enjoy Property (fMP)k.