摘要
Let Z/m Z be the ring of residual classes modulo m,and let A and B be nonempty subsets of Z/m Z.In this paper,the authors give the structure of A and B for which|A+B|=|A|+|B|-1=m-2.
基金
supported by the National Natural Science Foundation of China(Nos.12101007,12371003)
the Natural Science Foundation of Anhui Province(No.2008085QA06)。