W. Rudin proved the
following.
Theorem 1.1. Assume 0 < p < ∞, p≠2,4,6,⋯ . Let n be a positive integer. If
fi ∈ Lp(μ), gi ∈ Lp(ν) for 1 ≦ i ≦ n and
for all (z1,⋯,zn) ∈ Cn, then (f1,⋯,fn) and (g1,⋯,gn) are equimeasurable. Here as
usual Lp(μ) and Lp(ν) stand for p-th power integrable functions defined on finite
measure spaces (X,X,μ) and (Y,Y,ν) respectively. 𝒞 is the field of complex
numbers.
The purpose of this paper is to provide a new setting for Rudin’s result by
recasting it and its extension to real valued functions into the framework of the
theory of potential operators as formulated by K. Yosida.
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