Results 11 to 20 of about 1,576 (215)

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
doaj   +1 more source

Global analytic regularity for sums of squares of vector fields [PDF]

Transactions of the American Mathematical Society, 1998
We consider a class of operators in the form of a sum of squares of vector fields with real analytic coefficients on the torus and we show that the zero order term may influence their global analytic hypoellipticity. Also we extend a result of Cordaro-Himonas.
Cordaro, Paulo D., Himonas, A. Alexandrou   +1 more
openaire   +2 more sources

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
openaire   +3 more sources

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
doaj   +1 more source

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
openaire   +2 more sources

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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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.
openaire   +1 more source

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
openaire   +2 more sources

Some advances in analytic hypoellipticity

Bruno Pini Mathematical Analysis Seminar
We present a brief survey on the theory of the real analytic regularity for the solutions to sums of squares of vector fields satisfying the Hörmander condition.
Marco Mughetti
doaj   +1 more source

Hölder-continuity of the solutions for operators which are a sum of squares of vector fields plus a potential [PDF]

Proceedings of the American Mathematical Society, 1994
In this paper we study the local Hölder-regularity of weak solutions to L u +
DI FAZIO, Giuseppe, G. CITTI
openaire   +3 more sources