On the existence of positive periodic solutions to a Lotka Volterra cooperative population model with multiple delays

In this paper, the author studies the existence of positive periodic solutions to a Lotka Volterra cooperative population model with multiple delays as follows [GRAPHICS] By using Mawhin's continuation theorem of coincidence degree principle, a new result is obtained. The interesting thing is that the result is related to the delays, which is different from the corresponding ones of the known literature. (C) 2007 Elsevier Ltd. All rights reserved.