[en] The nth term of an automatic sequence is the output of a deterministic finite automaton fed with the representation of n in a suitable numeration system. In this paper, instead of considering automatic sequences built on a numeration system with a regular numeration language, we consider these built on languages associated with trees having periodic labeled signatures and, in particular, rational base numeration systems. We obtain two main characterizations of these sequences. The first one is concerned with r-block substitutions where r morphisms are applied periodically. In particular, we provide examples of such sequences that are not morphic. The second characterization involves the factors, or subtrees of finite height, of the tree associated with the numeration system and decorated by the terms of the sequence.
Disciplines :
Mathematics
Author, co-author :
Rigo, Michel ; Université de Liège - ULiège > Département de mathématique > Mathématiques discrètes
Stipulanti, Manon ; Université de Liège - ULiège > Département de mathématique > Département de mathématique
Language :
English
Title :
Automatic sequences: from rational bases to trees
Publication date :
2021
Journal title :
Discrete Mathematics and Theoretical Computer Science
ISSN :
1365-8050
eISSN :
1462-7264
Publisher :
Maison de l'informatique et des mathematiques discretes, France
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