| Résume | I will survey several recent results on the ergodicity and possible Krieger types of nonsingular Bernoulli actions. Given a countable group G and a base space X, consider the Bernoulli shift action of G on X^G, together with the product measure of a family of probability measures \mu_g on X. Even the basic question of ergodicity of this action turns out to be subtle. I will present general criteria to determine the Krieger type and show that all types, including II_\infty and III_0, can arise from nonsingular Bernoulli actions of amenable groups. |
