New results and open problems related to non-standard stringology

  • S. Muthukrishnan
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 937)


There are a number of string matching problems for which the best known algorithms rely on algebraic convolutions (an approach pioneered by Fischer and Paterson [FP74]). These include for instance the classical string matching with wild cards and the k-mismatches problem. In [MP94], the authors studied generalizations of these problems which they called the non-standard stringology. There they derived upper and lower bounds for non-standard string matching problems.

In this paper, we pose several novel problems in the area of non-standard stringology. Some we have been able to resolve here; others we leave open. Among the technical results in this paper are:
  1. 1.

    improved bounds for string matching when a symbol in the string matches at most d others (motivated by noisy string matching),

  2. 2.

    first-known bounds for approximately counting mismatches in noisy string matching as above, and

  3. 3.

    improved bounds for the k-witnesses problem and its applications.


Our results are obtained by using the probabilistic proof technique and randomized algorithmic methods; these techniques, although standard, have seldom been used in combinatorial pattern matching.


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Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • S. Muthukrishnan
    • 1
  1. 1.DIMACS, Rutgers University

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