Hypoellipticity and loss of derivatives with Appendix Analyticity and loss of derivatives

Joseph J. Kohn; Makhlouf Derridj; David S. Tartakoff

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Hypoellipticity and loss of derivatives with Appendix Analyticity and loss of derivatives

Joseph J. Kohn·Makhlouf Derridj·David S. Tartakoff

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Abstract

For each value of k, two complex vector fields satisfying the bracket condition are exhibited the sum of whose squares is hypoelliptic but not subelliptic - in fact the operator loses k-1 derivatives in Sobolev norms. In the Appendix it is proven that this operator is analytic hypoelliptic.

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Joseph J. Kohn, Makhlouf Derridj, David S. Tartakoff. 2006-01-26. Hypoellipticity and loss of derivatives with Appendix Analyticity and loss of derivatives. https://arxiv.org/abs/math/0601646

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