Stability and robust stability of non-autonomous linear differential equations with infinite delay

By the idea of comparison principle, we first introduce novel explicit criteria for $ \varrho $-stability general linear non-autonomous functional differential equations with infinite delay. Some characterizations time-independent exponential stability are also investigated. We then present a sufficient condition subject to time-varying structured perturbations. These results lead applications system unbounded delay and integro-differential examples given illustrate obtained results.