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

Categorical semantics and composition of tree transducers

In this thesis we see two new approaches to compose tree transducers and more general to fuse functional programs. The first abroach is based on initial algebras. We prove a new variant of the acid rain theorem for mutually recursive functions where the build function is substituted by a concrete functor. Moreover, we give a symmetric form (i.e. consumer and producer have the same syntactic form) of our new acid rain theorem where fusion is composition in a category and thus in particular associative. Applying this to compose top-down tree transducers yields the same result (on a syntactic level) as the classical top-down tree transducer composition. The second approach is based on free monads and monad transformers. In the same way as monoids are used in the theory of character string automata, we use monads in the theory of tree transducers. We generalize the notion of a tree transducer defining the monadic transducer, and we prove an according fusion theorem. Moreover, we prove that homomorphic monadic transducers are semantically equivalent. The latter makes it possible to compose syntactic classes of tree transducers (or particular functional programs) by simply composing endofunctors

Tree Transducers and Formal Methods (Dagstuhl Seminar 13192)

The aim of this Dagstuhl Seminar was to bring together researchers from various research areas related to the theory and application of tree transducers. Recently, interest in tree transducers has been revived due to surprising new applications in areas such as XML databases, security verification, programming language theory, and linguistics. This seminar therefore aimed to inspire the exchange of theoretical results and information regarding the practical requirements related to tree transducers

Multioperator Weighted Monadic Datalog

In this thesis we will introduce multioperator weighted monadic datalog (mwmd), a formal model for specifying tree series, tree transformations, and tree languages. This model combines aspects of multioperator weighted tree automata (wmta), weighted monadic datalog (wmd), and monadic datalog tree transducers (mdtt). In order to develop a rich theory we will define multiple versions of semantics for mwmd and compare their expressiveness. We will study normal forms and decidability results of mwmd and show (by employing particular semantic domains) that the theory of mwmd subsumes the theory of both wmd and mdtt. We conclude this thesis by showing that mwmd even contain wmta as a syntactic subclass and present results concerning this subclass

XML navigation and transformation by tree-walking automata and transducers with visible and invisible pebbles

Algorithms and the Foundations of Software technolog