For a measure-preserving T on a probability space and any A with μ(A) > 0, a.e. point of A returns to A under iteration of T infinitely often. First precursor to ergodic theory (1890).
For a measure-preserving T on a probability space and any A with μ(A) > 0, a.e. point of A returns to A under iteration of T infinitely often. First precursor to ergodic theory (1890).