ABSTRACT
Consider first a symmetric random walk, https://www.w3.org/1998/Math/MathML"> X n = ∑ k = 1 n ξ k , ( ξ k ) i . i . d , P ( ξ k = ± 1 ) = 1 2 , k = 1 , 2 , … , n ; n = 0 , 1 , , 2 , … , https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003216759/e7d667ff-34e1-4696-9d72-d545d9499230/content/unequ0011-01.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
