I don't understand the difference between this data structure [0] and buffered B-trees, as described in "Lower Bounds for External Memory Dictionaries", by Gert

I don't understand the difference between this data structure [0] and buffered B-trees, as described in "Lower Bounds for External Memory Dictionaries", by Gerth Stølting Brodal and Rolf Fagerberg [1], or in "On External Memory Graph Traversal" by Adam L. Buchsbaum, Michael Goldwasser, Suresh Venkatasubramanian, and Jeffery R. Westbrook [2]. Granted, this adds in path-copying, but I'm not sure what new innovation this has that merits the description "Hitchhiker trees are a newly invented (by @dgrnbrg) datastructure". 0: https://github.com/datacrypt-project/hitchhiker-tree/blob/master/doc/hitchhiker.adoc https://github.com/datacrypt-project/hitchhiker-tree/blob/ma... 1: http://www.cs.au.dk/~gerth/papers/alcomft-tr-03-75.pdf http://www.cs.au.dk/~gerth/papers/alcomft-tr-03-75.pdf 2: http://euler.slu.edu/~goldwasser/publications/SODA2000.pdf http://euler.slu.edu/~goldwasser/publications/SODA2000.pdf