Existence and global attractivity of unique positive periodic solution for a model of hematopoiesis

In this paper, we consider the generalized model of hematopoiesisx′(t)=−a(t)x(t)+∑i=1mbi(t)1+xn(t−τi(t)). By using a fixed point theorem, some criteria are established for the existence of the unique positive ω  -periodic solution x˜ of the above equation. In particular, we not only give the conclusion of convergence of xkxk to x˜, where {xk}{xk} is a successive sequence, but also show that x˜ is a global attractor of all other positive solutions.