Partial regularity for degenerate subelliptic systems associated with Hörmander’s vector fields

The paper is devoted to partial Hölder estimates for weak solutions of a class of degenerate subelliptic systems constructed by Hörmander’s vector fields. Assumptions on the systems are that coefficient matrix satisfies VMO condition in the sense of Carnot–Carathéodory distance in variables xx for fixed uu, and lower order terms satisfy the natural growth condition and the controllable growth condition, respectively.