Parsing with probabilistic strictly locally testable tree languages

Splicing Representations of Strictly Locally Testable Languages

The relationship between the family SH of simple splicing languages, which was recently introduced by A. Mateescu and coauthors, and the family SLT of strictly locally testable languages is clariied by establishing an ascending hierarchy of families fSiH : i ?1g of splicing languages for which SH = S1H and the union of the families is the family SLT. A procedure is given which, for an arbitrary...

From Regular to Strictly Locally Testable Languages

A classical result (often credited to Y. Medvedev) states that every language recognized by a finite automaton is the homomorphic image of a local language, over a much larger so-called local alphabet, namely the alphabet of the edges of the transition graph. Local languages are characterized by the value k = 2 of the sliding window width in the McNaughton and Papert’s infinite hierarchy of str...

A probabilistic extension of locally testable tree languages

Probabilistic k-testable models (usually known as k-gram models in the case of strings) can be easily identified from samples and allow for smoothing techniques to deal with unseen events. In this paper we introduce the family of stochastic k-testable tree languages and describe how these models can approximate any stochastic rational tree language. This is applied, as a particular case, to the...

Probabilistic k-Testable Tree Languages

A Decidable Characterization of Locally Testable Tree Languages

A regular tree language L is locally testable if membership of a tree in L depends only on the presence or absence of some fix set of neighborhoods in the tree. In this paper we show that it is decidable whether a regular tree language is locally testable. The decidability is shown for ranked trees and for unranked unordered trees.