Normalization of differential equations defining a CR structure

Intrinsic CR normal coordinates and the CR Yamabe problem

“…The main technical contribution of this paper is a new intrinsic construction of CR normal coordinates for an abstract CR manifold, in terms of which the asymptotic expansion of ^M(# £ ) can be calculated explicitly in terms of CR invariants of M at the base point. (H.-S. Luk [12] has given another intrinsic construction of CR normal coordinates; we have chosen a different approach because we need coordinates more closely related to pseudohermitian invariants. )…”