Multi-parameter Carnot-Caratheodory balls and the theorem of Frobenius
arXiv:0901.2910
Abstract
We study multi-parameter Carnot-Caratheodory balls, generalizing results due to Nagel, Stein, and Wainger in the single parameter setting. The main technical result is seen as a uniform version of the theorem of Frobenius. In addition, we study maximal functions associated to certain multi-parameter families of Carnot-Caratheodory balls.
Final version, to appear in Rev. Mat. Ibero