Handbook of Formal Languages
Introduction To Automata Theory, Languages, And Computation
Introduction To Automata Theory, Languages, And Computation
The Root of a Language and Its Complexity
DLT '01 Revised Papers from the 5th International Conference on Developments in Language Theory
The Power of One-Letter Rational Languages
DLT '01 Revised Papers from the 5th International Conference on Developments in Language Theory
Some non-semi-decidability problems for linear and deterministic context-free languages
CIAA'04 Proceedings of the 9th international conference on Implementation and Application of Automata
Primitive words are unavoidable for context-free languages
LATA'10 Proceedings of the 4th international conference on Language and Automata Theory and Applications
Hi-index | 0.00 |
For a set H of natural numbers, the H-power of a language L is the set of all words pk where p ∈ L and k ∈ H. The root of L is the set of all primitive words p such that pn belongs to L for some n ≥ 1. There is a strong connection between the root and the powers of a regular language L namely, the H-power of L for an arbitrary finite set H with 0, 1, 2 ∉ H is regular if and only if the root of L is finite. If the root is infinite then the H-power for most regular sets H is context-sensitive but not context-free. The stated property is decidable.