$L^q$ approximate controllability frequency criterion for linear difference delay equations with distributed delays

Based on an algebraic point of view and the realization theory developed by Y. Yamamoto, the present paper states a necessary and sufficient criterion, given in the frequency domain, for the $L^q$ approximate controllability in finite time of linear difference delay equations with distributed delays. Furthermore, an upper bound for the minimal time of the $L^q$ approximate controllability is obtained.