Handbook of formal languages, vol. 3
On the representation of finite deterministic 2-tape automata
Theoretical Computer Science
Automata, Languages, and Machines
Automata, Languages, and Machines
Modelization of deterministic rational relations
Theoretical Computer Science
Finite automata and their decision problems
IBM Journal of Research and Development
On relations defined by generalized finite automata
IBM Journal of Research and Development
Deterministic automata on unranked trees
FCT'05 Proceedings of the 15th international conference on Fundamentals of Computation Theory
How to train your multi bottom-up tree transducer
HLT '11 Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies - Volume 1
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We investigate rational relations over trees.Our starting point is the definition of rational tree relations via rational expressions by Raoult (Bull. Belg.Math. Soc. 1997). We develop a new class of automata, called asynchronous tree automata, which recognize exactly these relations. The automata theoretic approach is convenient for the solution of algorithmic problems (like the emptiness problem). The second contribution of this paper is a new subclass of the rational tree relations, called separate-rational tree relations, defined via a natural restriction on asynchronous tree automata. These relations are closed under composition, preserve regular tree languages, and generate precisely the regular sets in the unary case (all these properties fail for the general model), and they are still more powerful than, for instance, the automatic tree relations.