Operators and Matrices · Volume 3, Issue 4 Characterization of the unbounded bicommutant of C0 (N) contractions 03-35 Pages 589-598 DOI 10.7153/oam-03-35 Downloads Short PDF Full PDF PNG Authors R. T. W. Martin Keywords contractions of class C0 (N) unbounded double commutant H∞ functional calculus Subject classes 47A45 47A50