Parsing Boolean grammars over a one-letter alphabet using online convolution

  • Authors:
  • Alexander Okhotin;Christian Reitwieβner

  • Affiliations:
  • Department of Mathematics and Statistics, University of Turku, FI-20014 Turku, Finland;Julius-Maximilians-Universität Würzburg, Theoretische Informatik, D-97074 Würzburg, Germany and Universidad Técnica Federico Santa María, Departamento de Informática ...

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2012

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Abstract

Consider context-free grammars generating strings over a one-letter alphabet. For the membership problem for such grammars, stated as ''Given a grammar G and a string a^n, determine whether a^n is generated by G'', only a naive O(|G|@?n^2)-time algorithm is known. This paper develops a new algorithm solving this problem, which is based upon fast multiplication of integers, works in time |G|@?nlog^3n@?2^O^(^l^o^g^^^*^n^), and is applicable to context-free grammars augmented with Boolean operations, known as Boolean grammars. For unambiguous grammars, the running time of the algorithm is reduced to |G|@?nlog^2n@?2^O^(^l^o^g^^^*^n^). The algorithm is based upon (a simplification of) the online integer multiplication algorithm by Fischer and Stockmeyer [M.J. Fischer, L.J. Stockmeyer, Fast on-line integer multiplication, Journal of Computer and System Sciences 9 (3) (1974) 317-331].