Transforming Dependency Structures to Logical Forms for Semantic Parsing
Venue
Transactions of the Association for Computational Linguistics, vol. 4 (2016) (to appear)
Publication Year
2016
Authors
Siva Reddy, Oscar Täckström, Michael Collins, Tom Kwiatkowski, Dipanjan Das, Mark Steedman, Mirella Lapata
BibTeX
Abstract
The strongly typed syntax of grammar formalisms such as CCG, TAG, LFG and HPSG
offers a synchronous framework for deriving syntactic structures and semantic
logical forms. In contrast - partly due to the lack of a strong type system -
dependency structures are easy to annotate and have become a widely used form of
syntactic analysis for many languages. However, the lack of a type system makes a
formal mechanism for deriving logical forms from dependency structures challenging.
We address this by introducing a robust system based on the lambda calculus for
deriving neo-Davidsonian logical forms from dependency trees. These logical forms
are then used for semantic parsing of natural language to Freebase. Experiments on
the Free917 and WebQuestions datasets show that our representation is superior to
the original dependency trees and that it outperforms a CCG-based representation on
this task. Compared to prior work, we obtain the strongest result to date on
Free917 and competitive results on WebQuestions.
