On the entropy of regular languages
✍ Scribed by Tullio Ceccherini-Silberstein; Antonio Machı̀; Fabio Scarabotti
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 422 KB
- Volume
- 307
- Category
- Article
- ISSN
- 0304-3975
No coin nor oath required. For personal study only.
✦ Synopsis
Then the entropy decreases strictly: ent(L W ) ¡ ent(L). In this note we present a new proof of this fact, based on a method of Gromov, which avoids the Perron-Frobenius theory. This result applies to the regular languages of ÿnitely generated free groups and an additional application is presented.
📜 SIMILAR VOLUMES
A language is regular if it can be recognized by a ÿnite automaton. According to the pumping lemma, every inÿnite regular language contains a regular subset of the form uv + w, where u; v; w are words and v is not empty. It is known that every regular language can be expressed as ( i∈I uiv + i wi) ∪
The square of a language L is the set of all words pp where p ∈ L. The square of a regular language may be regular too or context-free or none of both. We give characterizations for each of these cases and show that it is decidable whether a regular language has one of these properties.
A regular language of the form UP' M' is called a single loop from the viewpoint of automata theory. It is known that every regular language can be expressed as (U,,,, U,L.;IV, )U F. where .4 is an index set, u,, ~1~ EX\*, c, EX~, i E A, and F is a finite set of words. This expression is called an s