Partial Permutations Comparison, Maintenance and Applications

Avivit Levy, Ely Porat, B. Riva Shalom

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This paper focuses on the concept of partial permutations and their use in algorithmic tasks. A partial permutation over Σ is a bijection πpar : Σ1 7→ Σ2 mapping a subset Σ1 ⊂ Σ to a subset Σ2 ⊂ Σ, where |Σ1| = |Σ2| (|Σ| denotes the size of a set Σ). Intuitively, two partial permutations agree if their mapping pairs do not form conflicts. This notion, which is formally defined in this paper, enables a consistent as well as informatively rich comparison between partial permutations. We formalize the Partial Permutations Agreement problem (PPA), as follows. Given two sets A1, A2 of partial permutations over alphabet Σ, each of size n, output all pairs (πi, πj), where πi ∈ A1, πj ∈ A2 and πi agrees with πj. The possibility of having a data structure for efficiently maintaining a dynamic set of partial permutations enabling to retrieve agreement of partial permutations is then studied, giving both negative and positive results. Applying our study enables to point out fruitful versus futile methods for efficient genes sequences comparison in database or automatic color transformation data augmentation technique for image processing through neural networks. It also shows that an efficient solution of strict Parameterized Dictionary Matching with One Gap (PDMOG) over general dictionary alphabets is not likely, unless the Strong Exponential Time Hypothesis (SETH) fails, thus negatively answering an open question posed lately.

Original languageEnglish
Title of host publication33rd Annual Symposium on Combinatorial Pattern Matching, CPM 2022
EditorsHideo Bannai, Jan Holub
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
ISBN (Electronic)9783959772341
StatePublished - 1 Jun 2022
Event33rd Annual Symposium on Combinatorial Pattern Matching, CPM 2022 - Prague, Czech Republic
Duration: 27 Jun 202229 Jun 2022

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
ISSN (Print)1868-8969


Conference33rd Annual Symposium on Combinatorial Pattern Matching, CPM 2022
Country/TerritoryCzech Republic

Bibliographical note

Publisher Copyright:
© Avivit Levy, Ely Porat, and B. Riva Shalom; licensed under Creative Commons License CC-BY 4.0


  • Color transformation
  • Dictionary matching with gaps
  • Genes comparison
  • Parameterized matching
  • Partial permutations
  • Partial words
  • SETH hypothesis


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