Abstract
The concept of hypoellipticity for degenerate elliptic boundary value problems is defined, and its relation with the hypoellipticity of certain pseudo-differential operators on the boundary is discussed (for second order equations). A theorem covering smoothness of solutions of boundary value problems such as a(x)∂u/∂n + b(x)u =f(x) for the Laplace equation is proved. An almost complete characterization of hypoelliptic boundary value problems for elliptic second order equations in two dimensions is given via analysis of hypoelliptic pseudo-differential operators in one variable.
Original language | English |
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Pages (from-to) | 311-328 |
Number of pages | 18 |
Journal | Transactions of the American Mathematical Society |
Volume | 217 |
DOIs | |
State | Published - 1976 |
Externally published | Yes |
Keywords
- Boundary value problems
- Elliptic equations
- Hypoelliptic pseudo-differential operators
- Ordinary pseudo-differential operators
- Symbols