00348nam a2200121Ia 4500082002000000100002000020245006700040260004900107300002700156490003300183500000500216700000500221  a515.42bF991.RE  aFurstenberg, H.  aRecurrence in ergodic theory and combinatorial number theoryb  aNew JerseybPrinceton University Pressc1980  axi, 202p. Index. Bibl.  aM. B. Porter lecturesv 1978  a  a