We study the problem of perturbations of C∞ -hypoelliptic operators by lower order terms. We show that hypoellipticity with a finite loss of derivatives of a linear partial differential operator P (with no assumption on the characteristic set), along with its formal adjoint P∗ , is stable under perturbations by lower order linear partial differential operators whose order depends on the loss of derivatives.
A remark on the stability of C∞-hypoellipticity under lower-order perturbations / Alberto Parmeggiani. - In: JOURNAL OF PSEUDO-DIFFERENTIAL OPERATORS AND APPLICATIONS. - ISSN 1662-9981. - STAMPA. - 6:2(2015), pp. 227-235. [10.1007/s11868-015-0118-8]
A remark on the stability of C∞-hypoellipticity under lower-order perturbations
PARMEGGIANI, ALBERTO
2015
Abstract
We study the problem of perturbations of C∞ -hypoelliptic operators by lower order terms. We show that hypoellipticity with a finite loss of derivatives of a linear partial differential operator P (with no assumption on the characteristic set), along with its formal adjoint P∗ , is stable under perturbations by lower order linear partial differential operators whose order depends on the loss of derivatives.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.