A method for computing the interval of delay values for which a differential-delay system

A test for determining the interval of delay values for which a delay-differential system is asymptotically stable is presented. I.e. an explicit method is given for calculating h* such that for 0 ? h ≪ h* a delay-differential system is stable where h is the delay length. Further it is shown that the system is not asymptotically stable for h = h*. Both retarded and neutral systems are discussed.