Automata and differentiable words

  • Authors:
  • Jean-Marc Fédou;Gabriele Fici

  • Affiliations:
  • -;-

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

Quantified Score

Hi-index 5.23

Visualization

Abstract

We exhibit the construction of a deterministic automaton that, given k0, recognizes the (regular) language of k-differentiable words. Our approach follows a scheme of Crochemore et al. based on minimal forbidden words. We extend this construction to the case of C^~-words, i.e., words differentiable arbitrarily many times. We thus obtain an infinite automaton for representing the set of C^~-words. We derive a classification of C^~-words induced by the structure of the automaton. Then, we introduce a new framework for dealing with C^~-words, based on a three letter alphabet. This allows us to define a compacted version of the automaton, that we use to prove that every C^~-word admits a repetition whose length is polynomially bounded.