A criterion for hypoellipticity of operators constructed from vector fields
A criterion for hypoellipticity of operators constructed from vector fields
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DOI:
10.1080/03605307908820107
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发表时间:
1979
影响因子:
1.9
通讯作者:
L. Rothschild
中科院分区:
文献类型:
--
作者:
L. Rothschild
0. Introduction. Suppose that X1, X 2,..., X P are smooth, real vector fields on a manifold M. Let L be the differential operator where xa= XX... x a=(alta2,..., a 1," 1 a2" Pp la (= p and the aa (x) are smooth, complex-valued functions. We seek the least restrictive conditions that will guarantee that L is hypoelliptic, ie that if Lf= g with g smooth in an open set U r then f is also smooth in U.Copyright O 1979 by Marcel Dekker, Inc. All Rights Reserved. Neither this work nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage and retrieval system, without permission in writing from the publisher.