Codice  QDD 68 
Titolo  On the lifting and approximation theorem for nonsmooth vector fields 
Data  20101021 
Autore/i  Bramanti, M.; Brandolini, L.; Pedroni, M. 
Link  Download full text  Pubblicato  Indiana University Mathematics Journal 
Abstract  We prove a version of RothschildStein s theorem of lifting and approximation and some related results in the context of nonsmooth Hormander s vector fields for which the highest order commutators are only Holder continuous. The theory explicitly covers the case of one vector field having weight two while the others have weight one. 
