Hypoelliptic operators with characteristic variety of codimension two and the wave equation. (English) Zbl 0468.35032

Sémin. Goulaouic-Schwartz 1979-1980, Équat. dériv. part., Exposé No. 11, 12 p. (1980).


35H10 Hypoelliptic equations
35P05 General topics in linear spectral theory for PDEs
35A20 Analyticity in context of PDEs
35A30 Geometric theory, characteristics, transformations in context of PDEs
35L05 Wave equation
35A22 Transform methods (e.g., integral transforms) applied to PDEs


Zbl 0375.35014
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