The spectrum of non-selfadjoint differential operators with periodic coefficients. (English. Russian original) Zbl 0199.14002
Sov. Math., Dokl. 4, 1312-1315 (1963); translation from Dokl. Akad. Nauk SSSR 152, 1563-1566 (1963).
MSC:
| 34L05 | General spectral theory of ordinary differential operators |
| 34D99 | Stability theory for ordinary differential equations |
| 34C25 | Periodic solutions to ordinary differential equations |
| 34M99 | Ordinary differential equations in the complex domain |
