Hörmander Operators

Hörmander Operators
English | 2023 | ISBN: 9811261687 | 722 Pages | PDF (True) | 8 MB
Hörmander operators are a class of linear second order partial differential operators with nonnegative characteristic form and smooth coefficients, which are usually degenerate elliptic-parabolic, but nevertheless hypoelliptic, that is highly regularizing. The study of these operators began with the 1967 fundamental paper by Lars Hörmander and is intimately connected to the geometry of vector fields.