The Gapped k-Deck Problem

Rebecca Golm, Mina Nahvi, Ryan Gabrys, Olgica Milenkovic

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The k-deck problem is concerned with finding the smallest positive integer S(k) such that there exist at least two strings of length S(k) that share the same k-deck, i.e., the multiset of subsequences of length k. We introduce the new problem of gapped k-deck reconstruction: For a given gap parameter s, we seek the smallest positive integer Gs(k) such that there exist at least two distinct strings of length Gs(k) that cannot be distinguished based on a "gapped"set of k-subsequences. The gap constraint requires the elements in the subsequences to be at least s positions apart within the original string. Our results are as follows. First, we show how to construct sequences sharing the same 2-gapped k-deck using a nontrivial modification of the recursive Morse-Thue string construction procedure. This establishes the first known constructive upper bound on G2(k). Second, we further improve this bound using the approach by Dudik and Schulman [6].

Original languageEnglish (US)
Title of host publication2022 IEEE International Symposium on Information Theory, ISIT 2022
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Electronic)9781665421591
StatePublished - 2022
Event2022 IEEE International Symposium on Information Theory, ISIT 2022 - Espoo, Finland
Duration: Jun 26 2022Jul 1 2022

Publication series

NameIEEE International Symposium on Information Theory - Proceedings
ISSN (Print)2157-8095


Conference2022 IEEE International Symposium on Information Theory, ISIT 2022


  • Gapped subsequences
  • Morse-Thue sequences
  • String reconstruction
  • k-deck

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Information Systems
  • Modeling and Simulation
  • Applied Mathematics


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