The purpose of this study is to devise general methods for making ordinary data structures persistent. Ordinary data structures are ephemeral in that any change to them destroys the old version, leaving only the new, modified version. Persistent data structures remember their past versions allowing both access and update operations to any version. Some general methods are known that can transform linked data structures into efficient persistent data structures. This study aims to devise new methods for making data structures persistent, in particular certain linked structures with arbitrary in degree for which no such methods are known. Persistent data structures are useful in numerous areas, including computational geometry, the implementation of very high level languages, and text editing.
