RWS-Diff: Flexible and Efficient Change Detection in Hierarchical Data, Jan Finis, Martin Raiber, Nikolaus Augsten, Robert Brunel, Alfons Kemper, Franz Färber. Presents an O(nlogn) approximation to the minimal tree edit sequence problem (tree diffing) which relies on hashing, random number generators, large-dimensional feature vectors, and techniques originating in computer vision to compare them.