## On certain partial differential operators of finite odd type

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- by A. Alexandrou Himonas PDF
- Trans. Amer. Math. Soc.
**324**(1991), 889-900 Request permission

## Abstract:

Let $P$ be a linear partial differential operator of order $m \geqslant 1$ with real-analytic coefficients defined in $\Omega$, an open set of ${\mathbb {R}^n}$, and let $\gamma$ be in the cotangent space of $\Omega$ minus the zero section. If $P$ is of odd finite type $k$ and if the Hörmander numbers are $1 = {k_1} < {k_2},{k_2}$ odd, then $P$ is analytic hypoelliptic at $\gamma$. These operators are not semirigid.## References

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## Additional Information

- © Copyright 1991 American Mathematical Society
- Journal: Trans. Amer. Math. Soc.
**324**(1991), 889-900 - MSC: Primary 35H05; Secondary 35A27
- DOI: https://doi.org/10.1090/S0002-9947-1991-1055570-9
- MathSciNet review: 1055570