Compactness of higher-order Sobolev embeddings
arXiv:1311.0155
Abstract
We study higher-order compact Sobolev embeddings on a domain endowed with a probability measure and satisfying certain isoperimetric inequality. Given , we present a condition on a pair of rearrangement-invariant spaces and which suffices to guarantee a compact embedding of the Sobolev space into . The condition is given in terms of compactness of certain one-dimensional operator depending on the isoperimetric function of . We then apply this result to the characterization of higher-order compact Sobolev embeddings on concrete measure spaces, including John domains, Maz'ya classes of Euclidean domains and product probability spaces, whose standard example is the Gauss space.