We study quasi-hyperbolicity of the delay semigroup associated with the equation , where is the history function and is the generator of a quasi-hyperbolic semigroup. We give conditions under which the associated solution semigroup of this equation generates a quasi-hyperbolic semigroup.
Shard Rastogi. Sachi Srivastava. "Quasi-Hyperbolicity and Delay Semigroups." Abstr. Appl. Anal. 2016 1 - 6, 2016. https://doi.org/10.1155/2016/1984874