An absolutely continuous measure on 
whose density has the form 
, where 
and 
are real-valued functions in 
, 
, exp is the exponential
function, and 
is the norm.
Helson-Szegö Measure
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Cite this as:
Weisstein, Eric W. "Helson-Szegö Measure." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Helson-SzegoeMeasure.html