Defintion of a Data Structure? Lately I have been looking around for a formal definition of a what a data structure is. I cannot find neither a paper, nor a book with such a definition. Even the famous "The Art of Computer Programming" is missing one. Even for just a linked data structure, e.g., binary search tree, I couldn't find one.

So, is there one? Perhaps a paper that is talking about it?

By formal definition I'm thinking of something like "A data structure is a tuple (Op, El, ..) where ...".
Data structures is nothing but the ways how data of different kinds can be structured in a systematic way. The actual definition may be somewhat lengthy and descriptive which can be found on different sources. But it is all about defining structures of your data that will satisfy your need to solve any particular problem.