Towards Broad-coverage Meaning Representation: The Case of Comparison Structures

Representing the underlying meaning of text has been a long-standing topic of interest in computational linguistics. Recently there has been a renewed interest in computational modeling of meaning for various tasks such as semantic parsing (Zelle and Mooney, 1996; Berant and Liang, 2014). Opendomain and broad-coverage semantic representation (Banarescu et al., 2013; Bos, 2008; Allen et al., 2008) is essential for many language understanding tasks such as reading comprehension tests and question answering. One of the most common way for expressing evaluative sentiment towards different entities is to use comparison. Comparison can happen in very simple structures such as ‘John is taller than Susan’, or more complicated constructions such as ‘The table is longer than the sofa is wide’. So far the computational semantics of comparatives and how they affect the meaning of the surrounding text has not been studied effectively. That is, the difference between the existing semantic and syntactic representation of comparatives has not been distinctive enough for enabling deeper understanding of a sentence. For instance, the general logical form representation of the sentence ‘John is taller than Susan’ using the Boxer system (Bos, 2008) is the following: