Some nonanalytichypoelliptic sums of squares of vector fields
Abstract
Certain secondorder partial differential operators, which are expressed as sums of squares of realanalytic vector fields in $\Bbb R^3$ and which are well known to be $C^\infty$ hypoelliptic, fail to be analytic hypoelliptic.
 Publication:

arXiv Mathematics eprints
 Pub Date:
 December 1991
 arXiv:
 arXiv:math/9201260
 Bibcode:
 1992math......1260C
 Keywords:

 Mathematics  Analysis of PDEs
 EPrint:
 4 pages