Sciweavers

DLT
2008
13 years 9 months ago
Universal Recursively Enumerable Sets of Strings
The present work clarifies the relation between domains of universal machines and r.e. prefix-free supersets of such sets. One such characterisation can be obtained in terms of the...
Cristian S. Calude, André Nies, Ludwig Stai...
DLT
2008
13 years 9 months ago
Relationally Periodic Sequences and Subword Complexity
By the famous theorem of Morse and Hedlund, a word is ultimately periodic if and only if it has bounded subword complexity, i.e., for sufficiently large n, the number of factors of...
Julien Cassaigne, Tomi Kärki, Luca Q. Zamboni
DLT
2008
13 years 9 months ago
Hierarchies of Piecewise Testable Languages
The classes of languages which are boolean combinations of languages of the form A a1A a2A . . . A a A , where a1, . . . , a A, k , for a fixed k 0, form a natural hierarchy wit...
Ondrej Klíma, Libor Polák
DLT
2008
13 years 9 months ago
Algorithmically Independent Sequences
Cristian S. Calude, Marius Zimand
DLT
2008
13 years 9 months ago
Tree Automata with Global Constraints
A tree automaton with global tree equality and disequality constraints, TAGED for short, is an automaton on trees which allows to test (dis)equalities between subtrees which may be...
Emmanuel Filiot, Jean-Marc Talbot, Sophie Tison
DLT
2007
13 years 9 months ago
Duplication Roots
Recently the duplication closure of words and languages has received much interest. We investigate a reversal of it: the duplication root reduces a word to a square-free one. After...
Peter Leupold