A choice of Sobolev spaces associated with ultraspherical expansions
A choice of Sobolev spaces associated with ultraspherical expansions
We discuss two possible definitions for Sobolev spaces associated with ultraspherical expansions.These definitions depend on the notion of higher order derivative.We show that in order to have an isomorphism between Sobolev and potential spaces, the higher order derivatives to be considered are not the iteration of the first order derivatives.Some …