The concept of Wiener chaos generalizes to an infinite-dimensional
setting the properties of orthogonal polynomials associated with
probability distributions on the real line. It plays a crucial role in
modern probability theory, with applications ranging from Malliavin
calculus to stochastic differential equations and from probabilistic
approximations to mathematical finance. This book is concerned with
combinatorial structures arising from the study of chaotic random
variables related to infinitely divisible random measures. The
combinatorial structures involved are those of partitions of finite
sets, over which Möbius functions and related inversion formulae are
defined. This combinatorial standpoint (which is originally due to Rota
and Wallstrom) provides an ideal framework for diagrams, which are
graphical devices used to compute moments and cumulants of random
variables. Several applications are described, in particular, recent
limit theorems for chaotic random variables. An Appendix presents a
computer implementation in MATHEMATICA for many of the formulae.