IKOMA at TAC2011: A Method for Recognizing Textual Entailment using Lexical-level and Sentence Structure-level features

This paper describes the Recognizing Textual Entailment (RTE) system that our teams developed for TAC 2011. Our system combines the entailment score calculated by lexicallevel matching with the machine-learningbased filtering mechanism using various features obtained from lexical-level, chunk-level and predicate argument structure-level information. In the filtering mechanism, we try to discard the T-H pairs that have high entailment score and are actually not entailment. That is, for filtering false positive T-H pairs caused by our lexical-level manner, we use additional information like features from word chunks and predicate-argument structures.