We first investigate some basic properties of dynamic equations on time scales,and propose contained curves to describe the jump direction of the discrete points.Then we perform qualitative analysis regarding the planar predator-prey systems on time scales,thereby obtain two theorems of this system.At last,we emulate application examples to discuss the parameters of the system.
Zhu Siming Li Yanhui (Math.and Computed Science Academy of Sun-Yatsen University,Guangzhou 510275) Rong Zhixin (IBM,Guangzhou 510620)
In this paper, a bridge between near-homogeneous and homogeneous vector fields in R 3 is found. By the relationship between homogeneous vector fields and the induced tangent vector fields of two-dimensional manifold S 2 , we prove the existence of at least 5 isolated closed orbits for a class of n + 1 (n ≥ 2) systems in R 3 , which are located on the five invariant closed cones of the system.
Lianhua Ma, Cuihong Yang , Xinan Zhang (School of Math. and Statistics, Central China Normal University, Wuhan 430079)
