Tree automata and attribute grammars

The translational mechanism of attribute grammars using tree automata are investigated. The pushdown tree-to-string transducer with a certain synchronization facility as a model to realize transformations by attribute grammars is proposed and its basic properties using tree-walking finite state automata are studied. To demonstrate the utility of this model, it is shown that noncircular attribute grammars are equally powerful as arbitrary attribute grammars, and a method is provided to show that a certain type of transformations is impossible by attribute grammars

Macro tree transducers

Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical topics like composition, decomposition, domains, and ranges of the induced translation classes. The extension with regular look-ahead is considered

Tree-Adjoining Grammars and Lexicalized Grammars

In this paper, we will describe a tree generating system called tree-adjoining grammar(TAG)and state some of the recent results about TAGs. The work on TAGS is motivated by linguistic considerations. However, a number of formal results have been established for TAGs, which we believe, would be of interest to researchers in tree grammars and tree automata. After giving a short introduction to TAG, we briefly state these results concerning both the properties of the string sets and tree sets (Section 2). We will also describe the notion of lexicalization of grammars (Section 3) and investigate the relationship of lexicalization to context-free grammars (CFGs) and TAGS (Section 4)

A generalization of tree automata and its relation to matrix grammars

In this thesis we introduce alpha and beta tree acceptors, generalizations of tree automata. The alpha tree acceptors recognize a tree by final symbol and the beta tree acceptors by final state. We show that alpha and beta tree acceptors recognize the same sets of Gorn trees and demonstrate that there are sets of Gorn trees not recognizably by any alpha tree acceptor. The tree automata are equivalent to the one state alpha tree acceptors. We show that the languages of alpha tree acceptors are exactly those of matrix grammars and the derivation trees of matrix grammars are recognized by alpha tree acceptors. Finally we show that nondeterministic alpha tree acceptors are no more powerful than deterministic alpha tree acceptors