Some characteristic theorems of union-preserving mapping on lattices;
格上保并映射的若干特征定理
Membership Functions of Fuzzy Union-Preserving Mapping and Fuzzy Meet-Preserving Mapping;
模糊保并、保交映射的隶属函数
This paper discusses real functions preserving some values of distance, a representation theorem of (strongly) distance-a preserving maps on R is obtained, and it is proved that even a map on R which preserves infinitely many values of distance is not necessarily isometric.