par Filiot, Emmanuel ;Servais, Frédéric
Référence Lecture notes in computer science, 7147 LNCS, page (251-263)
Publication Publié, 2012
Article révisé par les pairs
Résumé : Visibly Pushdown Transducers (VPT) form a subclass of pushdown transducers. In this paper, we investigate the extension of VPT with visibly pushdown look-ahead (VPT la). Their transitions are guarded by visibly pushdown automata that can check whether the well-nested subword starting at the current position belongs to the language they define. First, we show that VPT la are not more expressive than VPT, but are exponentially more succinct. Second, we show that the class of deterministic VPT la corresponds exactly to the class of functional VPT, yielding a simple characterization of functional VPT. Finally, we show that while VPT la are exponentially more succinct than VPT, checking equivalence of functional VPT la is, as for VPT, ExpT-C. As a consequence, we show that any functional VPT is equivalent to an unambiguous one. © 2012 Springer-Verlag.