Abstract
Necessary and sufficient conditions for the hypoellipticity of an ordinary differential operator with C ∞ coefficients in a neighborhood of a zero of finite order of the leading term are given. A sufficient condition for such an operator to be in a certain Hörmander class is also given.
| Original language | English |
|---|---|
| Pages (from-to) | 106-134 |
| Number of pages | 29 |
| Journal | Israel Journal of Mathematics |
| Volume | 13 |
| Issue number | 1-2 |
| DOIs | |
| State | Published - Mar 1972 |
| Externally published | Yes |