Order Structure and Lebesgue Decomposition of Positive Definite Operator Functions T. AndoWojciech Szymanski Indiana University Mathematics Journal 1986 text pdf 10.1512/iumj.1986.35.35008 10.1512/iumj.1986.35.35008 en Indiana Univ. Math. J. 35 (1986) 157 - 173 state-of-the-art mathematics http://iumj.org/access/