Removable singularities for degenerate elliptic Pucci operator on the Heisenberg group

In this paper, we study viscosity solutions to a class of degenerate elliptic Pucci operators modelled on the Heisenberg group, where the second order term is obtained by a composition of degenerate elliptic Pucci operator with the degenerate Heisenberg Hessian matrix. We study and answer the question: Which compact sets have the property that each viscosity subsolution outside this set, which is bounded below, can be extended to a viscosity subsolution on this set.