## Pseudo-differential operators with non regular symbols.(English)Zbl 0695.47047

Berlin: Freie Univ. Berlin, FB Math., Thesis. 139 p. (1985).
This work is concerned with pseudo-differential operators with nonsmooth symbols which belong to Hölder-Zygmund spaces. The author develops a calculus with pseudo-differential operators with such a symbol and extends several known properties of pseudo-differential operators with regular symbols such as the continuity and compacity from $$H^{s,p}$$ to $$H^{s-m,p}$$. Some applications to the construction of a parametrix for elliptic differential operators are given.
Reviewer: V.Barbu

### MSC:

 47Gxx Integral, integro-differential, and pseudodifferential operators 46E35 Sobolev spaces and other spaces of “smooth” functions, embedding theorems, trace theorems 35S05 Pseudodifferential operators as generalizations of partial differential operators