Top-Down K-Best A* Parsing

Adam Pauls, Dan Klein, Chris Quirk

Abstract: We propose a top-down algorithm for extracting k-best lists from a parser. Our algorithm, TKA* is a variant of the k-best A* (KA*) algorithm of Pauls and Klein (2009). In contrast to KA*, which performs an inside and outside pass before performing k-best extraction bottom up, TKA* performs only the inside pass before extracting k-best lists top down. TKA* maintains the same optimality and efficiency guarantees of KA*, but is simpler to both specify and implement.