BMO-scale of distribution on ? n

Let S′ be the class of tempered distributions. For ƒ ∈ S′ we denote by J ^−α ƒ the Bessel potential of ƒ of order α. We prove that if J ^−α ƒ ∈ BMO, then for any λ ∈ (0, 1), J ^−α (f)_λ ∈ BMO, where (f)_λ = λ⁻ⁿ f(φ(λ⁻¹)), φ ∈ S. Also, we give necessary and sufficient conditions in order that the Bessel potential of a tempered distribution of order α > 0 belongs to the VMO space.