A General Method of Researching the N-Ordered Fixed Point on a Metric Space with a Graph

In this paper, we propose a new perspective to discuss the N-order fixed point theory of set-valued and single-valued mappings. There are two aspects in our work: we first define a product metric space with a graph for the single-valued mapping whose conversion makes the results and proofs concise and straightforward, and then we propose an SG-contraction definition for set-valued mapping which is more general than some recent contraction’s definition. The results obtained in this paper extend and unify some recent results of other authors. Our method to discuss the N-order fixed point unifies N-order fixed point theory of set-valued and single-valued mappings.

赋有向图凸度量空间的Mann迭代算法

赋有向图的度量空间相比于一般的度量空间,在空间结构上更为复杂,有向图本身并不具有线性结构,在探究映射不动点的逼近问题上难度相对较大,从而受到了众多学者的广泛关注。首次通过在该空间中引入凸结构,给出了赋有向图凸度量空间的概念,并在该空间中得到G-单调非扩张映射在Mann迭代下生成序列的收敛性定理,并给出反例说明Mann迭代下生成序列不一定收敛到G-单调非扩张映射的不动点。