On the global attractivity controversy for a delay model of hematopoiesis

Recently, particular counterexamples were constructed to some theorems of a previous paper, concerning the global attractivity of the positive equilibrium for the delay equationp˙(t)=βpm(t-τ)1+pn(t-τ)-γp(t).The purpose of this note is to explore the underlying phenomenon from a more general point of view, and to give an explanation of the situation. A theorem is proved regarding attractivity properties of the equilibrium zero.