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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb. (N.S.), 1969 Volume 79(121), Number 3(7), Pages 381–404 (Mi sm3594)

This article is cited in 5 papers

A class of degenerate elliptic operators

A. V. Fursikov


Abstract: In a bounded region $G\subset R^n$ we consider an operator $A$ which is elliptic inside the region and degenerate on its boundary $\Gamma$. More precisely, the operator $A$ has the following form in the local coordinate system $(x',x_n)$, in which the boundary $\Gamma$ is given by the equation $x_n=0$ and $x_n>0$ for points in the region $G$:
$$ Au=\sum_{|l'|+l_n+\beta\leqslant2m}a_{l',l_n,\beta}(x',x_n)q^\beta x_n^{l_n}D_{x'}^{l'}D_{x_n}^{l_n}u $$
where $q$ is a parameter, and
$$ \sum_{|l'|+l_n+\beta=2m}a_{l',l_n,\beta}(x',0)q^\beta{\xi'}^{l'}{\xi_n}^{l^n}\ne0\quad\text{for}\quad|\xi|+|q|\ne0. $$

The operator $A$ will be proved Noetherian in certain spaces under the condition that $|q|$ is sufficiently large. In addition, some results will be obtained relating to how the smoothness of the solution of the equation $Au=f$ depends on the magnitude of the parameter.
A theorem is formulated concerning unique solvability in approperiate spaces for a class of degenerate parabolic operators.
Bibliography: 8 titles.

UDC: 517.43

MSC: 47F05, 35J70, 35K65

Received: 14.11.1968


 English version:
Mathematics of the USSR-Sbornik, 1969, 8:3, 357–382

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