Lower Bounds for the Number of Repetitions in 2D Strings

Paweł Gawrychowski, Samah Ghazawi, Gad M. Landau

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

Abstract

A 2D string is simply a 2D array. We continue the study of the combinatorial properties of repetitions in such strings over the binary alphabet, namely the number of distinct tandems, distinct quartics, and runs. First, we construct an infinite family of n× n 2D strings with Ω(n3) distinct tandems. Second, we construct an infinite family of n× n 2D strings with Ω(n2log n) distinct quartics. Third, we construct an infinite family of n× n 2D strings with Ω(n2log n) runs. This resolves an open question of Charalampopoulos, Radoszewski, Rytter, Waleń, and Zuba [ESA 2020], who asked if the number of distinct quartics and runs in an n× n 2D string is O(n2).

Original languageEnglish
Title of host publicationString Processing and Information Retrieval - 28th International Symposium, SPIRE 2021, Proceedings
EditorsThierry Lecroq, Hélène Touzet
PublisherSpringer Science and Business Media Deutschland GmbH
Pages179-192
Number of pages14
ISBN (Print)9783030866914
DOIs
StatePublished - 2021
Event28th International Symposium on String Processing and Information Retrieval, SPIRE 2021 - Virtual, Online
Duration: 4 Oct 20216 Oct 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12944 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference28th International Symposium on String Processing and Information Retrieval, SPIRE 2021
CityVirtual, Online
Period4/10/216/10/21

Bibliographical note

Funding Information:
P. Gawrychowski—Partially supported by the Bekker programme of the Polish National Agency for Academic Exchange (PPN/BEK/2020/1/00444). S. Ghazawi and G. M. Landau—Partially supported by the Israel Science Foundation grant 1475/18, and Grant No. 2018141 from the United States-Israel Binational Science Foundation (BSF).

Publisher Copyright:
© 2021, Springer Nature Switzerland AG.

Keywords

  • 2D strings
  • Quartics
  • Runs
  • Tandems

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science (all)

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