Theauthorsconsidertheexistenceandregularityoftheobliquederivativeproblem:{Pu=finΩ,^→tu=gonэΩwherePisasoc~adorderellipticdifferentialoperatoronR^n,ΩisaboundeddomaininR^nand^→tisaunitvectorfieldonthebouudaryofΩ(whichmaybetangentialtotheboundary).Allaboveareassumedwithlimitedsmoothnees.TheauthorsshowthatsolutionuhasanellipticgainfromfinHolderspaces(Theorem1.1).TheauthorsobtainL^nregualrityofsolutioninTbeorem1.3,whichgeneralizestheresultsin[7]tothelimitedsmoothcase.Someoftheapplicationnonlinearproblemsarealsodiscussed.
