Nuclear Embeddings in Weighted Function Spaces

compactifications and function spaces on weighted semigruops

chapter one is devoted to a moderate discussion on preliminaries, according to our requirements. chapter two which is based on our work in (24) is devoted introducting weighted semigroups (s, w), and studying some famous function spaces on them, especially the relations between go (s, w) and other function speces are invesigated. in fact this chapter is a complement to (32). one of the main fea...

On approximation numbers of Sobolev embeddings of weighted function spaces

We investigate asymptotic behaviour of approximation numbers of Sobolev embeddings between weighted function spaces of Sobolev–Hardy–Besov type with polynomials weights. The exact estimates are proved in almost all cases. © 2005 Elsevier Inc. All rights reserved.

Widths of embeddings in function spaces

We study the approximation, Gelfand and Kolmogorov numbers of embeddings in function spaces of Besov and Triebel-Lizorkin type. Our aim here is to provide sharp estimates in several cases left open in the literature and give a complete overview of the known results. We also add some historical remarks. AMS Classification: 41A45, 41A46, 46E35

Some limiting embeddings in weighted function spaces and related entropy numbers

The paper deals with weighted function spaces of type B p,q(R , w(x)) and F s p,q(R , w(x)), where w(x) is a weight function of at most polynomial growth. Of special interest are weight functions of type w(x) = (1 + |x|2)α/2 (log(2 + |x|))μ with α ≥ 0 and μ ∈ R. Our main result deals with estimates for the entropy numbers of compact embeddings between spaces of this type; more precisely, we may...

Optimal Sobolev embeddings and Function Spaces