Hitting Times for Transient Random Walks on Groups S. PortCharles Stone Indiana University Mathematics Journal 1968 text pdf 10.1512/iumj.1968.17.17069 10.1512/iumj.1968.17.17069 en Indiana Univ. Math. J. 17 (1968) 1117 - 1130 state-of-the-art mathematics http://iumj.org/access/