Enumeration and random generation of accessible automata

  • Authors:
  • Frédérique Bassino;Cyril Nicaud

  • Affiliations:
  • Institut Gaspard Monge, Université de Marne-la-Vallée, 77454 Marne-la-Vallée Cedex 2, France;Institut Gaspard Monge, Université de Marne-la-Vallée, 77454 Marne-la-Vallée Cedex 2, France

  • Venue:
  • Theoretical Computer Science
  • Year:
  • 2007

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Abstract

We present a bijection between the set A"n of deterministic and accessible automata with n states on a k-letters alphabet and some diagrams, which can themselves be represented as partitions of a set of kn+1 elements into n non-empty subsets. This combinatorial construction shows that the asymptotic order of the cardinality of A"n is related to the Stirling number {knn}. Our bijective approach also yields an efficient random sampler, for the uniform distribution, of automata with n states, its complexity is O(n^3^/^2), using the framework of Boltzmann samplers.