Imbedding theorems for elliptic and parabolic operators in the space C (Q917781)

The author deals with elliptic differential operators generated by a uniformly elliptic expression of order 2m with Hölder continuous coefficients. He gives a description of the imbedding of the domain of definitions in a class of functions whose highest derivatives (i.e. of order 2m) have a certain fractional degree of smoothness. The method uses an appropriate notion of derivative of fractional order. Analogous results are established for parabolic operators.