Let a1,a2,...,aN be positive real numbers whose sum equals 1. For a natural number i, let ni denote the number
of ak for which 21−i≥ak≥2−i holds. Prove that
i=1∑∞ni2−i≤4+log2N.
L. Leinder logarithmsreal analysisreal analysis unsolvedMiklos Schweitzerinequalities