Passive Learning of Deterministic Büchi Automata by Combinations of DFAs

Authors León Bohn , Christof Löding

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León Bohn
  • RWTH Aachen University, Germany
Christof Löding
  • RWTH Aachen University, Germany

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León Bohn and Christof Löding. Passive Learning of Deterministic Büchi Automata by Combinations of DFAs. In 49th International Colloquium on Automata, Languages, and Programming (ICALP 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 229, pp. 114:1-114:20, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


We present an algorithm that constructs a deterministic Büchi automaton in polynomial time from given sets of positive and negative example words. This learner constructs multiple DFAs using a polynomial-time active learning algorithm on finite words as black box using an oracle that we implement based on the given sample of ω-words, and combines these DFAs into a single DBA. We prove that the resulting algorithm can learn a DBA for each DBA-recognizable language in the limit by providing a characteristic sample for each DBA-recognizable language. We can only guarantee completeness of our algorithm for the full class of DBAs through characteristic samples that are, in general, exponential in the size of a minimal DBA for the target language. But we show that for each fixed k these characteristic samples are of polynomial size for the class of DBAs in which each subset of pairwise language-equivalent states has size at most k.

Subject Classification

ACM Subject Classification
  • Theory of computation → Automata over infinite objects
  • deterministic Büchi automata
  • learning from examples
  • learning in the limit
  • active learning


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