Exploring graph-algebraic CCG combinators for syntactic-semantic AMR parsing

Abstract

We describe a new approach to semantic parsing based on Combinatory Categorial Grammar (CCG). The grammar's semantic construction operators are defined in terms of a graph algebra, which allows our system to induce a compact CCG lexicon. We introduce an expectation maximisation algorithm which we use to filter our lexicon down to 2500 lexical templates. Our system achieves a semantic triple (Smatch) precision that is competitive with other CCG-based AMR parsing approaches.