“…This problem has been considered in Liu et al [
7] for a bounded operator
, and the case of a Miyadera–Voigt type operator has been investigated in Ouzahra et al [
8]. Moreover, in Ammari et al [
9], the case of 1−admissibility in Banach space has been considered. However, the 1−admissibility assumption prevents us to consider the case of Hilbert state space as in this case, the operator
will be necessary bounded (see Weiss [
10]).…”