On dilation theory for c_0-semigroups on Hilbert space Christian Le Merdy Indiana University Mathematics Journal 1996 text pdf 10.1512/iumj.1996.45.1191 10.1512/iumj.1996.45.1191 en Indiana Univ. Math. J. 45 (1996) 945 - 960 state-of-the-art mathematics http://iumj.org/access/