MathDB
Miklos Schweitzer 1971_5

Source:

October 29, 2008
real analysisreal analysis unsolved

Problem Statement

Let λ1λ2... \lambda_1 \leq \lambda_2 \leq... be a positive sequence and let K K be a constant such that k=1n1λk2<Kλn2  (n=1,2,...). \sum_{k=1}^{n-1} \lambda^2_k < K \lambda^2_n \;(n=1,2,...). Prove that there exists a constant K K' such that k=1n1λk<Kλn  (n=1,2,...). \sum_{k=1}^{n-1} \lambda_k < K' \lambda_n \;(n=1,2,...). L. Leindler