Matching Subsequences in Trees

TL;DR

This paper introduces the tree path subsequence problem for rooted, labeled trees, proposing it as a useful primitive for XML data querying and presenting algorithms that improve on existing time and space bounds.

Contribution

It formulates the tree path subsequence problem as a new query primitive for XML and offers improved algorithms for solving it.

Findings

New algorithms with better time bounds

Enhanced space efficiency

Applicability to XML data querying

Abstract

Given two rooted, labeled trees $P$ and $T$ the tree path subsequence problem is to determine which paths in $P$ are subsequences of which paths in $T$. Here a path begins at the root and ends at a leaf. In this paper we propose this problem as a useful query primitive for XML data, and provide new algorithms improving the previously best known time and space bounds.