Approximate Labelled Subtree Homeomorphism

Ron Y. Pinter, Oleg Rokhlenko, Dekel Tsur, Michal Ziv-Ukelson

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

19 Scopus citations


Given two undirected trees T and P, the Subtree Homeoraorphism Problem is to find whether T has a subtree t that can be transformed into P by removing entire subtrees, as well as repeatedly removing a degree-2 node and adding the edge joining its two neighbors. In this paper we extend the Subtree Homeomorphism Problem to a new optimization problem by enriching the subtree-comparison with node-to-node similarity scores. The new problem, denoted ALSH (Approximate Labelled Subtree Homeomorphism) is to compute the homeomorphic subtree of T which also maximizes the overall node-to-node resemblance. We describe an O(m2n /log m + mn log n) algorithm for solving ALSH on unordered, unrooted trees, where m and n are the number of vertices in P and T, respectively. We also give an O(mn) algorithm for rooted ordered trees.

Original languageEnglish
Title of host publicationCombinatorial Pattern Matching
Subtitle of host publication15th Annual Symposium, CPM 2004 Proceedings
EditorsSuleyman Cenk Sahinalp, S. Muthukrishnan, Ugur Dogrusoz
PublisherSpringer Verlag
Number of pages15
ISBN (Print)354022341X, 9783540223412
StatePublished - 2004
Externally publishedYes
Event15th Annual Symposium on Combinatorial Pattern Matching - Istanbul, Turkey
Duration: 5 Jul 20047 Jul 2004

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference15th Annual Symposium on Combinatorial Pattern Matching
Abbreviated titleCPM 2004

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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