A package merge is a relationship between two packages, where the contents of the target package (the one pointed at) is merged with the contents of the source package through specialization and redefinition, where applicable. This is a mechanism that should be used when elements of the same name are intended to represent the same concept, regardless of the package in which they are defined. A merging package will take elements of the same kind with the same name from one or more packages and merge them together into a single element using generalization and redefinitions. It should be noted that a package merge can be viewed as a short-hand way of explicitly defining those generalizations and redefinitions. The merged packages are still available, and the elements in those packages can be separately qualified. From an XMI point of view, it is either possible to exchange a model with all PackageMerges retained or a model where all PackageMerges have been transformed away (in which case package imports, generalizations, and redefinitions are used instead).