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Basic properties of nonsmooth Hörmander's vector fields and Poincaré's inequality

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Published/Copyright: July 1, 2013

Abstract.

We consider a family of vector fields

() defined in some bounded domain and assume that the Xi satisfy Hörmander's rank condition of some step r in , and . We extend to this nonsmooth context some results which are well known for smooth Hörmander's vector fields, namely: some basic properties of the distance induced by the vector fields, the doubling condition, Chow's connectivity theorem, and, under the stronger assumption , Poincaré's inequality. By known results, these facts also imply a Sobolev embedding. All these tools allow us to draw some consequences about second order differential operators modeled on these nonsmooth Hörmander's vector fields:

where is a uniformly elliptic matrix of functions.

Received: 2009-04-02
Published Online: 2013-07-01
Published in Print: 2013-07-01

© 2013 by Walter de Gruyter Berlin Boston

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