Intermediate Optimal Gevrey Exponents Occur
نویسنده
چکیده
Hypoellipticity in Gevrey classesG 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 s is greater than or equal to an optimal exponent that may take on any rational value.
منابع مشابه
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