The Strong Szego Limit Theorem for Circular Arcs Harold Widom Indiana University Mathematics Journal 1972 text pdf 10.1512/iumj.1972.21.21022 10.1512/iumj.1972.21.21022 en Indiana Univ. Math. J. 21 (1972) 277 - 283 state-of-the-art mathematics http://iumj.org/access/