Comment, with reply, on "Vertex implications of stability for a class of delay-differential interval system" by K.D. Kim and N.K. Bose

The commenters disagree with the claim by K.D. Kim and N.K. Bose (see ibid., vol.37, no.7, p.969-972, 1990) that for an important special case of delay-differential systems when the characteristic equation is describable by certain quasi-polynomials, the vertex implication for stability does hold. The commenters show that this claim is not true. What may be true is that the vertex implication holds for the very limited case of systems which are known as stable independent of delay. The authors' reply is included.<
>