Ideal Weights: Assymptotically Optimal Versions of Doubling, Absolute Continuity, and Bounded Mean Oscillation.
We propose the study of some questions related to the Dunkl-Hermite semigroup. Essentially, we characterize the images of the Dunkl-Hermite-Sobolev space, and , , under the Dunkl-Hermite semigroup. Also, we consider the image of the space of tempered distributions and we give Paley-Wiener type theorems for the transforms given by the Dunkl-Hermite semigroup.
On a metric measure space (X,ϱ,μ), consider the weight functions if ϱ(x,z₀) < 1, if ϱ(x,z₀) ≥ 1, if ϱ(x,z₀) < 1, if ϱ(x,z₀) ≥ 1, where z₀ is a given point of X, and let be an operator kernel satisfying for all x,y ∈ X such that ϱ(x,y) < 1, for all x,y ∈ X such that ϱ(x,y)≥ 1, where 0 < a < min(d,D), and d and D are respectively the local and global volume growth rate of the space X. We determine conditions on a, α₀, α₁, β₀, β₁ ∈ ℝ for the Hardy-Littlewood-Sobolev operator...
For large classes of indices, we characterize the weights u, v for which the Hardy operator is bounded from into . For more general operators of Hardy type, norm inequalities are proved which extend to weighted amalgams known estimates in weighted -spaces. Amalgams of the form , 1 < p,q < ∞ , q ≠ p, , are also considered and sufficient conditions for the boundedness of the Hardy-Littlewood maximal operator and local maximal operator in these spaces are obtained.
We give characterizations of Besov and Triebel-Lizorkin spaces and in smooth domains via convolutions with compactly supported smooth kernels satisfying some moment conditions. The results for s ∈ ℝ, 0 < p,q ≤ ∞ are stated in terms of the mixed norm of a certain maximal function of a distribution. For s ∈ ℝ, 1 ≤ p ≤ ∞, 0 < q ≤ ∞ characterizations without use of maximal functions are also obtained.