Invariant Mean Characterizations of von Neumann Algebras Alan Paterson Indiana University Mathematics Journal 1992 text pdf 10.1512/iumj.1992.41.41013 10.1512/iumj.1992.41.41013 en Indiana Univ. Math. J. 41 (1992) 233 - 252 state-of-the-art mathematics http://iumj.org/access/