Model Theory and the mean ergodic theorem for abelian unitary actions
  We explore connections between von Neumann's mean ergodic theorem and concepts of model theory. As an application we present a proof Wiener's generalization of von Neumann's result in which the group acting on the Hilbert space $\mathcal{H}$ is any abelian group of unitary transformations of $\mathcal{H}$. 
Eduardo Due\~nez and Jos\'e Iovino
math.LO math.DS