Expansion of Perturbed Random Variables Based on Generalized Wiener Functionals

By means of the Malliavin calculus, we present an expansion formula for the distribution of a random variableFhaving a stochastic expansionF=F0+R, whereF0is an easily tractable random variable andRis the remainder term. From this result, we derive an expansion of the distribution of the scale mixturesZof a normal random variableZby a scale random variables. Applications to shrinkage estimators of the Stein type are mentioned