Results 11 to 20 of about 51,079 (125)

Gevrey regularity for a class of sums of squares of monomial vector fields

Advances in Mathematics, 2020
The paper is devoted to the problem of the analytic and Gevrey hypoellipticity of the sum-of-squares operators. The characteristic manifold is assumed to be symplectic of dimension 2. In the case of a second order degeneration, this grants analytic hypoellipticity, see for example \textit{F. Trèves} [Commun. Partial Differ. Equations 3, 475--642 (1978;
Bove A., Mughetti M.
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Hypoellipticity and Loss of Derivatives of Sums of Squares of complex Vector Fields

The Journal of Geometric Analysis
Abstract In this paper I survey some recent results I obtained about the hypoellipticity of sums of squares of complex vector fields that allow for a generalization of Kohn’s Thm. A, and give a new result about hypoellipticity with a loss of many derivatives that shows that Kohn’s Thm. B holds in a more general setting.
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Hypoellipticity and nonhypoellipticity for sums of squares of complex vector fields [PDF]

Analysis & PDE, 2013
In this talk we consider the analogue of Kohn’s operator but with a point singularity, P = BB∗ +B∗(t2` + x)B, B = Dx + ix Dt. We show that this operator is hypoelliptic and Gevrey hypoelliptic in a certain range, namely k < `q, with Gevrey index `q `q−k = 1 + k `q−k . Outside the above range of the parameters, i.e. when k ≥ `q, the operator is not even
BOVE, ANTONIO, MUGHETTI, MARCO, D. S. Tartakoff   +2 more
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Analytic Hypoellipticity and the Treves Conjecture

Bruno Pini Mathematical Analysis Seminar, 2016
We are concerned with the problem of the analytic hypoellipticity; precisely, we focus on the real analytic regularity of the solutions of sums of squares with real analytic coefficients. Treves conjecture states that an operator of this type is analytic
Marco Mughetti
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COMPARISON OF CRUSTAL DEFORMATION RATES ESTIMATED FROM SEISMIC AND GPS DATA ON THE BISHKEK GEODYNAMIC POLYGON

Геодинамика и тектонофизика, 2017
The Bishkek geodynamic polygon (BGP, 41.5–43.5° N – 73–77° E) is located within the central segment of the North Tien Shan seismic zone, in the junction zone of the Tien Shanorogene and the Turan plate (Fig. 1).
N. A. Sycheva, A. N. Mansurov
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Least-squares inversion for density-matrix reconstruction [PDF]

, 1997
We propose a method for reconstruction of the density matrix from measurable time-dependent (probability) distributions of physical quantities. The applicability of the method based on least-squares inversion is - compared with other methods - very ...
A. Zucchetti, C. F. Gauss, C. Kurtsiefer, D. J. S. Robinson, D. Leibfried, D. T. Smithey, D. T. Smithey, D.-G. Welsch, G. H. Golub, G. M. D’Ariano, G. M. D’Ariano, G. M. D’Ariano, G. M. D’Ariano, G. S. Agarwal, H. Kühn, H. Paul, K. Banaszek, K. Vogel, M. Freyberger, M. G. A. Paris, M. G. Raymer, M. Shapiro, M. W. Noel, N. G. Walker, P. J. Bardroff, P. Kowalczyk, P. M. Morse, S. Schiller, S. Wallentowitz, S. Wallentowitz, T. J. Dunn, T. J. Dunn, T. Kiss, T. Opatrný, T. Opatrný, T. Opatrný, Th. Richter, Th. Richter, U. Janicke, U. Leonhardt, U. Leonhardt, U. Leonhardt, U. Leonhardt, V. Bužek, W. H. Press, W. Vogel, W. Vogel, Y. Lai, Z. Hradil   +48 more
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Analytic hypoellipticity for sums of squares of vector fields [PDF]

Annales Polonici Mathematici, 1998
This paper is a synthetic, lucid and up to date review of the status of the theory concerning analytic hypoellipticity of sums of squares operators. First the author discusses the local theory; there are two famous conjectures by François Treves, that spurred quite a number of papers on the subject.
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Global hypoellipticity for sums of squares of vector fields of infinite type.

Matemática Contemporânea, 1998
This paper deals with the global \(C^\infty\) hypoellipticity for a class of second-order differential operators on the torus. These operators are sums of squares of real-valued vector fields. A necessary and sufficient condition for global \(C^\infty\) hypoellipticity is proved.
Gerson Petronilho, A. Himonas
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Loss of derivatives for systems of complex vector fields and sums of squares [PDF]

Proceedings of the American Mathematical Society, 2011
We discuss, both for systems of complex vector fields and for sums of squares, the phenomenon discovered by Kohn of hypoellipticity with loss of derivatives.
Khanh T. V., Pinton S., Zampieri G.
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Local real analyticity of solutions for sums of squares of non-linear vector fields

Journal of Differential Equations, 2005
AMS-LaTeX, 10 ...
TARTAKOFF D., ZANGHIRATI, Luisa
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