On Randomized Generation of Slowly Synchronizing Automata

Authors Costanza Catalano, Raphaël M. Jungers

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Author Details

Costanza Catalano
  • Gran Sasso Science Institute, Viale Francesco Crispi 7, L'Aquila, Italy
Raphaël M. Jungers
  • ICTEAM Institute, UCLouvain, Avenue Georges Lemaîtres 4-6, Louvain-la-Neuve, Belgium

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Costanza Catalano and Raphaël M. Jungers. On Randomized Generation of Slowly Synchronizing Automata. In 43rd International Symposium on Mathematical Foundations of Computer Science (MFCS 2018). Leibniz International Proceedings in Informatics (LIPIcs), Volume 117, pp. 48:1-48:16, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2018)


Motivated by the randomized generation of slowly synchronizing automata, we study automata made of permutation letters and a merging letter of rank n-1 . We present a constructive randomized procedure to generate synchronizing automata of that kind with (potentially) large alphabet size based on recent results on primitive sets of matrices. We report numerical results showing that our algorithm finds automata with much larger reset threshold than a mere uniform random generation and we present new families of automata with reset threshold of Omega(n^2/4) . We finally report theoretical results on randomized generation of primitive sets of matrices: a set of permutation matrices with a 0 entry changed into a 1 is primitive and has exponent of O(n log n) with high probability in case of uniform random distribution and the same holds for a random set of binary matrices where each entry is set, independently, equal to 1 with probability p and equal to 0 with probability 1-p , when np-log n - > infty as n - > infty .

Subject Classification

ACM Subject Classification
  • Mathematics of computing → Combinatorics
  • Mathematics of computing → Random graphs
  • Theory of computation → Randomness, geometry and discrete structures
  • Synchronizing automata
  • random automata
  • Cerný conjecture
  • automata with simple idempotents
  • primitive sets of matrices


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