Shell evolution and structure of exotic nuclei

The evolution of shell structure in exotic nuclei is discussed. There are two major origins of this shell evolution: one is related to the spin-isospin dependent central part of the nucleon-nucleon interaction, while the other is the tensor interaction. I shall mainly discuss the latter case, since the former one has been discussed to some detail. It will be suggested that the tensor interaction can change the shell structure, for instance, by varying the spin-orbit splitting considerably as a function ofN andZ.