On the Unicellularity of Finite Convolution Operators Richard Frankfurt Indiana University Mathematics Journal 1977 text pdf 10.1512/iumj.1977.26.26016 10.1512/iumj.1977.26.26016 en Indiana Univ. Math. J. 26 (1977) 223 - 232 state-of-the-art mathematics http://iumj.org/access/