摘要 : In this article, we prove the continuity of the horizontal gradient near a C-1,C-Dini non-characteristic portion of the boundary for solutions to Gamma(0,Dini) perturbations of horizontal Laplaceans as in (1.1) below, where the sc... 展开 In this article, we prove the continuity of the horizontal gradient near a C-1,C-Dini non-characteristic portion of the boundary for solutions to Gamma(0,Dini) perturbations of horizontal Laplaceans as in (1.1) below, where the scalar term is in scaling critical Lorentz space L(Q, 1) with Q being the homogeneous dimension of the group. This result can be thought of both as a sharpening of the Gamma(1,alpha) boundary regularity result in [4] as well as a subelliptic analogue of the main result in [1] restricted to linear equations. 收起