... and coordination, drafted the manuscript, participated in the sequence alignment, and read and approved the final manuscript.Competing interests The authors declare that they have no competing ... groupsare Banach spaces. In 1978, Rassias [3] proved a generalization of Hyers’ theorem for additive mappings. Furthermore, in 1994, a general ization of the Rassias’ theorem wasobtained by ... baak@hanyang.ac.kr3Department of Mathematics,Research Institute for NaturalSciences, Hanyang University, Seoul133-791, KoreaFull list of author information isavailable at the end of the articleAbstractUsing...