Properties of Quasi-Relabeling Tree Bimorphisms

Syntax-Directed Translations and Quasi-alphabetic Tree Bimorphisms - Revisited

Quasi-alphabetic tree bimorphisms [Steinby and Tîrn uc : Syntax-Directed Translations and Quasi-Alphabetic Tree Bimorphisms. Proc. CIAA, LNCS 4783:265 276, 2007] are reconsidered. It is known that the class of (string) translations de ned by such bimorphisms coincides with the class of syntax-directed translations. This result is extended to a smaller class of tree bimorphisms namely (linear an...

Properties of quasi-alphabetic tree bimorphisms

We study the class of quasi-alphabetic relations, i.e., tree transformations de ned by tree bimorphisms (';L; ) with '; quasi-alphabetic tree homomorphisms and L a regular tree language. We present a canonical representation of these relations; as an immediate consequence, we get the closure under union. Also, we show that they are not closed under intersection and complement, and do not preser...

Syntax-Directed Translations and Quasi-alphabetic Tree Bimorphisms

Synchronous Grammars as Tree Transducers

Tree transducer formalisms were developed in the formal language theory community as generalizations of finite-state transducers from strings to trees. Independently, synchronous tree-substitution and -adjoining grammars arose in the computational linguistics community as a means to augment strictly syntactic formalisms to provide for parallel semantics. We present the first synthesis of these ...

Synchronous Context-Free Tree Grammars

We consider pairs of context-free tree grammars combined through synchronous rewriting. The resulting formalism is at least as powerful as synchronous tree adjoining grammars and linear, nondeleting macro tree transducers, while the parsing complexity remains polynomial. Its power is subsumed by context-free hypergraph grammars. The new formalism has an alternative characterization in terms of ...