Local C^n-Operational Calculus Shmuel Kantorovitz Indiana University Mathematics Journal 1968 text pdf 10.1512/iumj.1968.17.17007 10.1512/iumj.1968.17.17007 en Indiana Univ. Math. J. 17 (1968) 181 - 187 state-of-the-art mathematics http://iumj.org/access/