Semantic parsing with LFG and conceptual representations

Abstract

A semantic parser is presented which aims at the attainment of a high linguistic coverage and an extendibility to many languages. To this end, a frequency distionary for Italian has been classified following LFG theoretical framework and a general decoder has been implemented to pass from the syntactic. to the semantic and conceptual levels. Syntactic structural derivation is produced by complete lexical froms, lexical redundancy rules and an extended phrase structure grammar which has been implemented in Prolog using XGs. Semantic and conceptual representation are produced following Jackendoff's system of conceptual representations plus a number of additions to compute time reference mainly inspired by J. Allen's system (1983a, b). We believe that a text rethorical organizations is mainly governed by linguistic principles like the alternation of FOCUS and TOPIC, the use of definiteness to qualify referring expressions, etc. We describe two algorithm to analyse the level of text: Logical Form, which provides scope assignment to quantified expressions; an algorithm for anaphora resolution which incorporates linguistic information and a number of psycholinguistic heuristic. Finally, we briefly describe how the inference engine provided by KL-ONE is integrated into the previous modules to produce semantic entailment and linguistic inferences.