Corrections to Upper Functions for Symmetric Processes with Stationary, Independent Increments, 21 (1971), 177-185 Bert Fristedt Indiana University Mathematics Journal 1974 text pdf 10.1512/iumj.1974.23.23038 10.1512/iumj.1974.23.23038 en Indiana Univ. Math. J. 23 (1974) 445 - 445 state-of-the-art mathematics http://iumj.org/access/