There has been much progress on the qualitative properties of difference equations, which include results on stability and attractivity, results on oscillation and other topics.

• 关于差分方程定性性质(稳定性、吸引性、振动性等)的研究成果很多,但关于差分方程周期解的研究成果相对较少,其主要原因是缺乏必要的工具处理离散系统周期解存在性问题。