Balanced Grammars and Their Languages

Balanced Grammars and Their Languages

Balanced Context-Free Grammars, Hedge Grammars and Pushdown Caterpillar Automata

The XML community generally takes trees and hedges as the model for XML document instances and element content. In contrast, Berstel and Boasson have discussed XML documents in the framework of extended context-free grammar, modeling XML documents as Dyck strings and schemas as balanced grammars. How can these two models be brought closer together? We examine the close relatioship between Dyck ...

Alternating Regular Tree Grammars in the Framework of Lattice-Valued Logic

In this paper, two different ways of introducing alternation for lattice-valued (referred to as {L}valued)  regular tree grammars and {L}valued top-down tree automata are compared. One is the way which defines the alternating regular tree grammar, i.e., alternation is governed by the non-terminals of the grammar and the other is the way which combines state with alternation. The first way is ta...

Breeding Grammars: Grammatical Inference with a Genetic Algorithm

This paper presents a genetic algorithm used to infer context-free grammars from legal and illegal examples of a language. It discusses the representation of grammar rules in the form of bitstringsby way of an interval coding scheme, genetic operators for reproduction of grammars, and the method of evaluating the fitness of grammars with respect to the training examples. Results are reported on...

Algebraic properties of structured context-free languages: old approaches and novel developments

The historical research line on the algebraic properties of structured CF languages initiated by McNaughton’s Parenthesis Languages has recently attracted much renewed interest with the Balanced Languages, the Visibly Pushdown Automata languages (VPDA), the Synchronized Languages, and the Height-deterministic ones. Such families preserve to a varying degree the basic algebraic properties of Reg...