Intermediate Optimal Gevrey Exponents Occur
Functional Analysis
2008-02-03 v1
Abstract
Hypoellipticity in Gevrey classes is characterized for a simple family of sums of squares of vector fields satisfying the bracket hypothesis, with analytic coefficients. It is shown that hypoellipticity holds if and only if is greater than or equal to an optimal exponent that may take on any rational value.
Keywords
Cite
@article{arxiv.math/9603213,
title = {Intermediate Optimal Gevrey Exponents Occur},
author = {Michael Christ},
journal= {arXiv preprint arXiv:math/9603213},
year = {2008}
}