Computing all subtree repeats in ordered trees

We consider the problem of computing all subtree repeats in a given labeled ordered tree. We first transform the tree to a string representing its postfix notation, and then present an algorithm based on the bottom-up technique to solve it. The proposed algorithm consists of two phases: the preprocessing phase and the phase where all subtree repeats are computed. The linear time and space complexity of the proposed algorithm are important parts of its quality.

► Problem: computing all subtree repeats in a given unlabeled or labeled ordered tree.
► String representation of tree and bottom-up technique.
► Linear time and space complexity.