By using Gaines and Mawhin's continuation theorem of coincidence degree theory and constructing Lyapunov functionals,a set of easily verifiable sufficient conditions are derived for the existence and global attractivity of a positive periodic solution to a predator-prey system with delays and impulses.
Ren Yaping(School of Statistic and Math.,Yunnan University of Finance and Economics,Kunming 650221) Li Yongkun(Dept. of Math.,Yunnan University,Kunming 650091)
By using Krasnoselskiis fixed point theorem on a suitable cone, several existence results and corresponding properties of positive solutions of nonlocal boundary value problem for nonlinear retarded differential equation are obtained.