Analytic Operators and Spectral Decompositions F. Vasilescu Indiana University Mathematics Journal 1985 text pdf 10.1512/iumj.1985.34.34037 10.1512/iumj.1985.34.34037 en Indiana Univ. Math. J. 34 (1985) 705 - 722 state-of-the-art mathematics http://iumj.org/access/