Normalization of Sequential Top-Down Tree-to-Word Transducers

Abstract. We study normalization of deterministic sequential top-down tree-to-word transducers (stws), that capture the class of deterministic top-down nested-word to word transducers. We identify the subclass of earliest stws (estws) that yield unique normal forms when minimized. The main result of this paper is an effective normalization procedure for stws. It consists of two stages: we first convert a given stw to an equivalent estw, and then, we minimize the estw.