%0 Journal Article %T AF-equivalence relations and their cocycles %A Jean Renault %J Mathematics %D 2001 %I arXiv %X After a review of some of the main results about hyperfinite equivalence relations and their cocycles in the measured setting, we give a definition of a topological AF-equivalence relation. We show that every cocycle is cohomologous to a quasi-product cocycle. We then study the problem of determining the quasi-invariant probability measures admitting a given cocycle as their Radon-Nikodym derivative. %U http://arxiv.org/abs/math/0111182v1