Optimal superprimitivity testing for strings
Information Processing Letters
Fibonacci morphisms and Sturmian words
Theoretical Computer Science
Efficient detection of quasiperiodicities in strings
Theoretical Computer Science
Sturmian words: structure, combinatorics, and their arithmetics
Theoretical Computer Science - Special issue: formal language theory
A characterization of substitutive sequences using return words
Discrete Mathematics
Quasiperiodicity and string covering
Theoretical Computer Science
Lyndon factorization of sturmian words
Discrete Mathematics
Episturmian words and some constructions of de Luca and Rauzy
Theoretical Computer Science
Episturmian words and episturmian morphisms
Theoretical Computer Science
Automata on Infinite Words, Ecole de Printemps d'Informatique Théorique,
String pattern matching for a deluge survival kit
Handbook of massive data sets
Conjugacy and episturmian morphisms
Theoretical Computer Science
Automatic Sequences: Theory, Applications, Generalizations
Automatic Sequences: Theory, Applications, Generalizations
Applied Combinatorics on Words (Encyclopedia of Mathematics and its Applications)
Applied Combinatorics on Words (Encyclopedia of Mathematics and its Applications)
Quasiperiodic Sturmian words and morphisms
Theoretical Computer Science
Conjugacy of morphisms and Lyndon decomposition of standard Sturmian words
Theoretical Computer Science
Characterizations of finite and infinite episturmian words via lexicographic orderings
European Journal of Combinatorics
A characterization of fine words over a finite alphabet
Theoretical Computer Science
A local balance property of episturmian words
DLT'07 Proceedings of the 11th international conference on Developments in language theory
Sturmian and episturmian words: a survey of some recent results
CAI'07 Proceedings of the 2nd international conference on Algebraic informatics
Optimality of some algorithms to detect quasiperiodicities
Theoretical Computer Science
On the fixed points of the iterated pseudopalindromic closure operator
Theoretical Computer Science
Hi-index | 5.23 |
Recently the second two authors characterized quasiperiodic Sturmian words, proving that a Sturmian word is non-quasiperiodic if and only if, it is an infinite Lyndon word. Here we extend this study to episturmian words (a natural generalization of Sturmian words) by describing all the quasiperiods of an episturmian word, which yields a characterization of quasiperiodic episturmian words in terms of their directive words. Even further, we establish a complete characterization of all episturmian words that are Lyndon words. Our main results show that, unlike the Sturmian case, there is a much wider class of episturmian words that are non-quasiperiodic, besides those that are infinite Lyndon words. Our key tools are morphisms and directive words, in particular normalized directive words, which we introduced in an earlier paper. Also of importance is the use of return words to characterize quasiperiodic episturmian words, since such a method could be useful in other contexts.