On special families of morphisms related to δ-matching and don't care symbols

Richard Cole, Costas Iliopoulos, Thierry Lecroq, Wojciech Plandowski, Wojciech Rytter

Research output: Contribution to journalArticlepeer-review


The δ-matching problem is a special version of approximate pattern-matching, motivated by applications in musical information retrieval, where the alphabet Σ is an interval of integers. We investigate relations between δ-matching and pattern-matching with don't care symbol * (a symbol matching every symbol, including itself). We show that the δ-matching is reducible to k instances of pattern-matching with don't cares. We investigate how the numbers δ and k are related by introducing δ-distinguishing families ℋ of morphisms. The size of ℋ corresponds to k. We show that for minimal families ℋ we have |ℋ| = Θ(δ).

Original languageEnglish (US)
Pages (from-to)227-233
Number of pages7
JournalInformation Processing Letters
Issue number5
StatePublished - Mar 16 2003


  • Combinatorial problems
  • Don't care symbols
  • Pattern-matching
  • δ-matching

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Signal Processing
  • Information Systems
  • Computer Science Applications


Dive into the research topics of 'On special families of morphisms related to δ-matching and don't care symbols'. Together they form a unique fingerprint.

Cite this