(2)'. (3)'. Furthermore, the constants c, d occurring in (1) and (I)' can be taken to be ... Remark. We remark that conditions (2) and (2)' also imply the two equivalent.
transactions of the american mathematical society Volume 320, Number 2, August 1990
COMPARISON OF COMMUTING ONE-PARAMETER GROUPS OF ISOMETRIES OLA BRATTELI, HIDEKJ KUROSE AND DEREK W. ROBINSON Abstract. Let a , ß be two commuting strongly continuous one-parameter groups of isometries on a Banach space j/ with generators 0 such that
