共 50 条
- [41] ESSENTIAL SPECTRUM OF SECOND-ORDER DEGENERATE ELLIPTIC OPERATORS JOURNAL OF THE LONDON MATHEMATICAL SOCIETY-SECOND SERIES, 1974, 8 (AUG): : 463 - 482
- [45] CONTINUOUS SPECTRUM OF SECOND-ORDER DIFFERENTIAL OPERATORS DOKLADY AKADEMII NAUK SSSR, 1973, 212 (06): : 1301 - 1304
- [47] Second-order subelliptic operators on Lie groups III: Hölder continuous coefficients Calculus of Variations and Partial Differential Equations, 1999, 8 : 327 - 363
- [48] HYPOELLIPTICITY OF SECOND-ORDER DIFFERENTIAL OPERATORS WITH REAL COEFFICIENTS COMPTES RENDUS HEBDOMADAIRES DES SEANCES DE L ACADEMIE DES SCIENCES SERIE A, 1974, 278 (16): : 1045 - 1046
- [49] On the spectrum of second-order differential operators with complex coefficients PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 1999, 455 (1984): : 1235 - 1257