2021/09/27 by Peláez, José Ángel, de la Rosa, Elena · 3 citations
#Complex Variables (math.CV) #FOS: Mathematics #Functional Analysis (math.FA)
paper · doi:10.48550/arxiv.2109.12944
For any pair (n,p), n∈ℕ and 01 such that inf0≤ r<1 \frac∫r1ω(s) ds∫1-(1-r)/(k)1 ω(s) ds>1. In this paper we extend this result to the setting of fractional derivatives. Being precise, for an analytic function f(z)=∑n=0^∞ \widehatf(n) zn we consider the fractional derivative Dμ(f)(z)=∑n=0∞ \frac\widehatf(n)μ2n+1 zn induced by a radial weight μ∈ D, where μ2n+1=∫01 r2n+1μ(r) dr. Then, we prove that for any p∈ (0,∞), the Littlewood-Paley equivalence ∫_\mathbbD |f(z)|p ω(z) dA(z)\asymp ∫_\mathbbD|Dμ(f)(z)|p[∫|z|1μ(s) ds]pω(z) dA(z) holds for any analytic function f in \mathbbD if and only if ω\inD. We also prove that for any p∈ (0,∞), the inequality ∫_\mathbbD |Dμ(f)(z)|p [∫|z|1μ(s) ds]pω(z) dA(z) \lesssim ∫_\mathbbD |f(z)|p ω(z) dA(z) holds for any analytic function f in \mathbbD if and only if ω∈ \widehatD.