English

Lorentz--Karamata spaces

Functional Analysis 2023-05-01 v4

Abstract

In this paper, we consider Lorentz--Karamata spaces with slowly varying functions and provide a comprehensive study of their properties. We consider Lorentz--Karamata functionals over an arbitrary sigma-finite measure space equipped with a non-atomic measure and the corresponding Lorentz--Karamata spaces. We characterise non-triviality of said spaces, then study when they are equivalent to a Banach function space and obtain a complete characterisation. We compute the fundamental function of said spaces and describe the corresponding endpoint spaces. We further provide a complete characterisation of when the Lorentz--Karamata spaces defined using non-increasing rearrangement are equivalent to those defined using maximal function. We provide a complete description of the associate spaces of Lorentz--Karamata spaces. We also treat other topics like embeddings, absolute continuity of the (quasi)norm, and Boyd indices.

Keywords

Cite

@article{arxiv.2006.14455,
  title  = {Lorentz--Karamata spaces},
  author = {Dalimil Peša},
  journal= {arXiv preprint arXiv:2006.14455},
  year   = {2023}
}
R2 v1 2026-06-23T16:37:34.848Z