Learning Cover Context-Free Grammars from Structural Data

  • Mircea Marin
  • Gabriel Istrate
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8687)

Abstract

We consider the problem of learning an unknown context-free grammar when the only knowledge available and of interest to the learner is about its structural descriptions with depth at most ℓ. The goal is to learn a cover context-free grammar (CCFG) with respect to ℓ, that is, a CFG whose structural descriptions with depth at most ℓ agree with those of the unknown CFG. We propose an algorithm, called LA, that efficiently learns a CCFG using two types of queries: structural equivalence and structural membership. We show that LA runs in time polynomial in the number of states of a minimal deterministic finite cover tree automaton (DCTA) with respect to ℓ. This number is often much smaller than the number of states of a minimum deterministic finite tree automaton for the structural descriptions of the unknown grammar.

Keywords

automata theory and formal languages structural descriptions grammatical inference 

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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Mircea Marin
    • 1
  • Gabriel Istrate
    • 1
    • 2
  1. 1.Department of Computer ScienceWest University of TimişoaraTimişoaraRomania
  2. 2.e-Austria Research InstituteTimişoaraRomania

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