On the state and computational complexity of the reverse of acyclic minimal DFAs

  • Authors:
  • Galina Jir$#225/skov$#225/;Tom$#225/$#353/ Masopust

  • Affiliations:
  • Mathematical Institute, Slovak Academy of Sciences, Ko$#353/ice, Slovak Republic;Institute of Mathematics, Academy of Sciences of the Czech Republic, Brno, Czech Republic

  • Venue:
  • CIAA'12 Proceedings of the 17th international conference on Implementation and Application of Automata
  • Year:
  • 2012

Quantified Score

Hi-index 0.00

Visualization

Abstract

We study the state complexity of the reverse of acyclic minimal deterministic finite automata, and the computational complexity of the following problem: Given an acyclic minimal DFA, is the minimal DFA for the reverse also acyclic? Note that we allow self-loops in acyclic automata. We show that there exists a language accepted by an acyclic minimal DFA such that the minimal DFA for its reverse is exponential with respect to the number of states, and we establish a tight bound on the state complexity of the reverse of acyclic DFAs. We also give a direct proof of the fact that the minimal DFA for the reverse is acyclic if and only if the original acyclic minimal DFA satisfies a certain structural property, which can be tested in quadratic time.