2018/05/25 by Leonetti, Paolo
#Classical Analysis and ODEs (math.CA) #FOS: Mathematics #Primary: 40A35. Secondary: 26A12
paper · doi:10.48550/arxiv.1805.10366
Let (xn) be a positive real sequence decreasing to 0 such that the series ∑n xn is divergent and \liminfn xn+1/xn>1/2. We show that there exists a constant θ∈ (0,1) such that, for each ℓ>0, there is a subsequence (xnk) for which ∑k xnk=ℓ and xnk=O(θk).