Abstract
AbstractWe introduce general translations as solutions to Cauchy or Dirichlet problems. This point of view allows us to handle for instance the heat-diffusion semigroup as a translation. With the given examples, Kolmogorov–Riesz characterization of compact sets in certain $$L^p_\mu $$
L
μ
p
spaces is given. Pego-type characterizations are also derived. Finally, for some examples, the equivalence of the corresponding modulus of smoothness and K-functional is pointed out.
Funder
Budapest University of Technology and Economics
Publisher
Springer Science and Business Media LLC
Subject
Algebra and Number Theory,Analysis