Electronic Journal of Differential Equations,
Vol. 2008(2008), No. 158, pp. 1-14.

Title: Positive periodic solutions for an impulsive
       ratio-dependent predator-prey system with delays
   
Authors: Yan Liu     (Huaqiao Univ., Quanzhou, China)
         Quanyi Wang (Huaqiao Univ., Quanzhou, China)

Abstract:
 In this paper, we study a periodic ratio-dependent predator-prey
 system of two species with impulse and multiple time delays.
 By means of analysis techniques and the continuation theorem
 of coincidence degree theory, we obtain sufficient conditions
 for the existence of positive periodic solutions of the system.
 Our results extend  previous results obtained in [9].

Submitted May 28, 2008. Published December 03, 2008.
Math Subject Classifications: 34K45, 34K13, 92D25.
Key Words: Positive periodic solution; ratio-dependent;
           time delay; predator-prey system; impulse; 
	   coincidence degree theory.