On Kohn’s sums of squares of complex vector fields [PDF]
Matemática Contemporânea, 2022 This is a survey of some recent alternative way of proving a subelliptic estimate, first proven by J. J. Kohn, for certain sums of squares of complex vector fields.
A. Parmeggiani
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On the microlocal regularity of the analytic vectors for "sums of squares" of vector fields [PDF]
Mathematische Zeitschrift, 2022 We prove via FBI-transform a result concerning the microlocal Gevrey regularity of analytic vectors for operators sums of squares of vector fields with real-valued real analytic coefficients of Hormander type, thus providing a microlocal version, in the ...
Chinni, G, Derridj, M
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On the Gevrey regularity for Sums of Squares of vector fields, study of some models [PDF]
Journal of Differential Equations, 2018 The micro-local Gevrey regularity of a class of "sums of squares" with real analytic coefficients is studied in detail.
Chinni, Gregorio
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Local Hardy and Rellich inequalities for sums of squares of vector fields [PDF]
Advances in Differential Equations, 2016 We prove local refined versions of Hardy's and Rellich's inequalities as well as of uncertainty principles for sums of squares of vector fields on bounded sets of smooth manifolds under certain assumptions on the vector fields. We also give some explicit
Ruzhansky, Michael, Suragan, Durvudkhan
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Hypoellipticity and Non Hypoellipticity for Sums of Squares of Complex Vector Fields
Bruno Pini Mathematical Analysis Seminar, 2011 Bruno Pini Mathematical Analysis Seminar, Seminars ...
Antonio Bove
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Singular Sums of Squares of Degenerate Vector Fields [PDF]
Proceedings of the American Mathematical Society, 2006 19 ...
Bove, Antonio +3 more
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On the regularity of the solutions and of analytic vectors for “sums of squares”
Bruno Pini Mathematical Analysis Seminar, 2023 We present a brief survey on some recent results concerning the local and global regularity of the solutions for some classes/models of sums of squares of vector fields with real-valued real analytic coefficients of H"ormander type.
Gregorio Chinni
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On the Gevrey hypo-ellipticity of sums of squares of vector fields [PDF]
Annales de l'Institut Fourier, 2004 The article studies a second-order linear differential operator of the type -L= X 1 2 +⋯+X r 2 , i. e., a sum of squares of real, and real-analytic, vector fields X i . The conjectured necessary and sufficient condition for analytic hypo- ellipticity, based on the Poisson stratification of the characteristic variety, is recalled in simple analytic and ...
BOVE, ANTONIO, F. Treves
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Global analytic regularity for sums of squares of vector fields [PDF]
Transactions of the American Mathematical Society, 1998 Les deux auteurs considérent ici la question de la regularite analytique globale du certains types d'operateurs différentiels, qui sont des sous-classes de la classe des opérateurs de L. Hörmander \[ P=\sum^r_{j=1} x^2_j+X_0+a. \] Contrairement au cas de la régularité \(C^\infty\) (bien clarifié par L.
Cordaro, Paulo D. +1 more
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Some nonanalytic-hypoelliptic sums of squares of vector fields [PDF]
Bulletin of the American Mathematical Society, 1992 Certain second-order partial differential operators, which are expressed as sums of squares of real-analytic vector fields in R 3 {\mathbb {R}^3} and which are well known to be C ∞ {C^\infty } hypoelliptic, fail to be analytic
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