In this paper, we propose tree edit distance with variables, which is an extension of the tree edit distance to handle trees with variables and has a potential application to measuring the similarity between mathematical formulas. We analyze the computational complexity of several variants of this model. In particular, we show that the problem is NP-complete for ordered trees. We also show for unordered trees that the problem of deciding whether or not the distance is 0 is graph isomorphism complete but can be solved in polynomial time if the maximum outdegree of input trees is bounded by a constant. We also present parameterized and exponential-time algorithms for ordered and unordered cases, respectively.
@InProceedings{akutsu_et_al:LIPIcs.ISAAC.2022.44, author = {Akutsu, Tatsuya and Mori, Tomoya and Nakamura, Naotoshi and Kozawa, Satoshi and Ueno, Yuhei and Sato, Thomas N.}, title = {{On the Complexity of Tree Edit Distance with Variables}}, booktitle = {33rd International Symposium on Algorithms and Computation (ISAAC 2022)}, pages = {44:1--44:14}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-258-7}, ISSN = {1868-8969}, year = {2022}, volume = {248}, editor = {Bae, Sang Won and Park, Heejin}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2022.44}, URN = {urn:nbn:de:0030-drops-173295}, doi = {10.4230/LIPIcs.ISAAC.2022.44}, annote = {Keywords: Tree edit distance, unification, parameterized algorithms} }
Feedback for Dagstuhl Publishing