1992/10/30 by Wenzel, Joerg
#46E #FOS: Mathematics #Functional Analysis (math.FA)
paper · doi:10.48550/arxiv.math/9210208
Given any Banach space X, let L2X denote the Banach space of all measurable functions f:[0,1]→ X for which ||f||2:=(int01 ||f(t)||2 dt)1/2 is finite. We show that X is a UMD--space (see \citeBUR:1986) if and only if limn||f-Sn(f)||2=0 for all f∈ L2X, where Sn(f):=sumi=0n-1 (f,wi)wi is the n--th partial sum associated with the Walsh system (wi).